Stop panic in govet-levee CI job

Signed-off-by: Davanum Srinivas <davanum@gmail.com>

vendor/golang.org/x/tools/AUTHORS

@@ -1,3 +0,0 @@
-# This source code refers to The Go Authors for copyright purposes.
-# The master list of authors is in the main Go distribution,
-# visible at http://tip.golang.org/AUTHORS.

vendor/golang.org/x/tools/CONTRIBUTORS

@@ -1,3 +0,0 @@
-# This source code was written by the Go contributors.
-# The master list of contributors is in the main Go distribution,
-# visible at http://tip.golang.org/CONTRIBUTORS.

vendor/golang.org/x/tools/container/intsets/sparse.go

@@ -10,7 +10,6 @@
 // space-efficient than equivalent operations on sets based on the Go
 // map type.  The IsEmpty, Min, Max, Clear and TakeMin operations
 // require constant time.
-//
 package intsets // import "golang.org/x/tools/container/intsets"
 
 // TODO(adonovan):
@@ -37,7 +36,6 @@ import (
 //
 // Sparse sets must be copied using the Copy method, not by assigning
 // a Sparse value.
-//
 type Sparse struct {
 	// An uninitialized Sparse represents an empty set.
 	// An empty set may also be represented by
@@ -105,7 +103,6 @@ func ntz(x word) int {
 // is the Euclidean remainder.
 //
 // A block may only be empty transiently.
-//
 type block struct {
 	offset     int                 // offset mod bitsPerBlock == 0
 	bits       [wordsPerBlock]word // contains at least one set bit
@@ -122,7 +119,6 @@ func wordMask(i uint) (w uint, mask word) {
 
 // insert sets the block b's ith bit and
 // returns true if it was not already set.
-//
 func (b *block) insert(i uint) bool {
 	w, mask := wordMask(i)
 	if b.bits[w]&mask == 0 {
@@ -135,7 +131,6 @@ func (b *block) insert(i uint) bool {
 // remove clears the block's ith bit and
 // returns true if the bit was previously set.
 // NB: may leave the block empty.
-//
 func (b *block) remove(i uint) bool {
 	w, mask := wordMask(i)
 	if b.bits[w]&mask != 0 {
@@ -238,7 +233,6 @@ func (b *block) forEach(f func(int)) {
 
 // offsetAndBitIndex returns the offset of the block that would
 // contain x and the bit index of x within that block.
-//
 func offsetAndBitIndex(x int) (int, uint) {
 	mod := x % bitsPerBlock
 	if mod < 0 {
@@ -438,9 +432,8 @@ func (s *Sparse) Clear() {
 //
 // This method may be used for iteration over a worklist like so:
 //
-// 	var x int
-// 	for worklist.TakeMin(&x) { use(x) }
-//
+//	var x int
+//	for worklist.TakeMin(&x) { use(x) }
 func (s *Sparse) TakeMin(p *int) bool {
 	if s.IsEmpty() {
 		return false
@@ -466,7 +459,6 @@ func (s *Sparse) Has(x int) bool {
 // f must not mutate s.  Consequently, forEach is not safe to expose
 // to clients.  In any case, using "range s.AppendTo()" allows more
 // natural control flow with continue/break/return.
-//
 func (s *Sparse) forEach(f func(int)) {
 	for b := s.first(); b != &none; b = s.next(b) {
 		b.forEach(f)
@@ -1021,11 +1013,11 @@ func (s *Sparse) String() string {
 // preceded by a digit, appears if the sum is non-integral.
 //
 // Examples:
-//              {}.BitString() =      "0"
-//           {4,5}.BitString() = "110000"
-//            {-3}.BitString() =      "0.001"
-//      {-3,0,4,5}.BitString() = "110001.001"
 //
+//	        {}.BitString() =      "0"
+//	     {4,5}.BitString() = "110000"
+//	      {-3}.BitString() =      "0.001"
+//	{-3,0,4,5}.BitString() = "110001.001"
 func (s *Sparse) BitString() string {
 	if s.IsEmpty() {
 		return "0"
@@ -1060,7 +1052,6 @@ func (s *Sparse) BitString() string {
 
 // GoString returns a string showing the internal representation of
 // the set s.
-//
 func (s *Sparse) GoString() string {
 	var buf bytes.Buffer
 	for b := s.first(); b != &none; b = s.next(b) {

vendor/golang.org/x/tools/go/ast/astutil/enclosing.go

@@ -22,9 +22,9 @@ import (
 // additional whitespace abutting a node to be enclosed by it.
 // In this example:
 //
-//              z := x + y // add them
-//                   <-A->
-//                  <----B----->
+//	z := x + y // add them
+//	     <-A->
+//	    <----B----->
 //
 // the ast.BinaryExpr(+) node is considered to enclose interval B
 // even though its [Pos()..End()) is actually only interval A.
@@ -43,10 +43,10 @@ import (
 // interior whitespace of path[0].
 // In this example:
 //
-//              z := x + y // add them
-//                <--C-->     <---E-->
-//                  ^
-//                  D
+//	z := x + y // add them
+//	  <--C-->     <---E-->
+//	    ^
+//	    D
 //
 // intervals C, D and E are inexact.  C is contained by the
 // z-assignment statement, because it spans three of its children (:=,
@@ -54,12 +54,11 @@ import (
 // interior whitespace of the assignment.  E is considered interior
 // whitespace of the BlockStmt containing the assignment.
 //
-// Precondition: [start, end) both lie within the same file as root.
-// TODO(adonovan): return (nil, false) in this case and remove precond.
-// Requires FileSet; see loader.tokenFileContainsPos.
-//
-// Postcondition: path is never nil; it always contains at least 'root'.
-//
+// The resulting path is never empty; it always contains at least the
+// 'root' *ast.File.  Ideally PathEnclosingInterval would reject
+// intervals that lie wholly or partially outside the range of the
+// file, but unfortunately ast.File records only the token.Pos of
+// the 'package' keyword, but not of the start of the file itself.
 func PathEnclosingInterval(root *ast.File, start, end token.Pos) (path []ast.Node, exact bool) {
 	// fmt.Printf("EnclosingInterval %d %d\n", start, end) // debugging
 
@@ -135,6 +134,7 @@ func PathEnclosingInterval(root *ast.File, start, end token.Pos) (path []ast.Nod
 		return false // inexact: overlaps multiple children
 	}
 
+	// Ensure [start,end) is nondecreasing.
 	if start > end {
 		start, end = end, start
 	}
@@ -162,7 +162,6 @@ func PathEnclosingInterval(root *ast.File, start, end token.Pos) (path []ast.Nod
 // tokenNode is a dummy implementation of ast.Node for a single token.
 // They are used transiently by PathEnclosingInterval but never escape
 // this package.
-//
 type tokenNode struct {
 	pos token.Pos
 	end token.Pos
@@ -183,7 +182,6 @@ func tok(pos token.Pos, len int) ast.Node {
 // childrenOf returns the direct non-nil children of ast.Node n.
 // It may include fake ast.Node implementations for bare tokens.
 // it is not safe to call (e.g.) ast.Walk on such nodes.
-//
 func childrenOf(n ast.Node) []ast.Node {
 	var children []ast.Node
 
@@ -488,7 +486,6 @@ func (sl byPos) Swap(i, j int) {
 // TODO(adonovan): in some cases (e.g. Field, FieldList, Ident,
 // StarExpr) we could be much more specific given the path to the AST
 // root.  Perhaps we should do that.
-//
 func NodeDescription(n ast.Node) string {
 	switch n := n.(type) {
 	case *ast.ArrayType:

vendor/golang.org/x/tools/go/ast/astutil/imports.go

@@ -22,8 +22,11 @@ func AddImport(fset *token.FileSet, f *ast.File, path string) (added bool) {
 // If name is not empty, it is used to rename the import.
 //
 // For example, calling
+//
 //	AddNamedImport(fset, f, "pathpkg", "path")
+//
 // adds
+//
 //	import pathpkg "path"
 func AddNamedImport(fset *token.FileSet, f *ast.File, name, path string) (added bool) {
 	if imports(f, name, path) {
@@ -270,8 +273,8 @@ func DeleteNamedImport(fset *token.FileSet, f *ast.File, name, path string) (del
 			}
 			if j > 0 {
 				lastImpspec := gen.Specs[j-1].(*ast.ImportSpec)
-				lastLine := fset.Position(lastImpspec.Path.ValuePos).Line
-				line := fset.Position(impspec.Path.ValuePos).Line
+				lastLine := fset.PositionFor(lastImpspec.Path.ValuePos, false).Line
+				line := fset.PositionFor(impspec.Path.ValuePos, false).Line
 
 				// We deleted an entry but now there may be
 				// a blank line-sized hole where the import was.

vendor/golang.org/x/tools/go/ast/astutil/rewrite.go

@@ -41,7 +41,6 @@ type ApplyFunc func(*Cursor) bool
 // Children are traversed in the order in which they appear in the
 // respective node's struct definition. A package's files are
 // traversed in the filenames' alphabetical order.
-//
 func Apply(root ast.Node, pre, post ApplyFunc) (result ast.Node) {
 	parent := &struct{ ast.Node }{root}
 	defer func() {
@@ -65,8 +64,8 @@ var abort = new(int) // singleton, to signal termination of Apply
 // c.Parent(), and f is the field identifier with name c.Name(),
 // the following invariants hold:
 //
-//   p.f            == c.Node()  if c.Index() <  0
-//   p.f[c.Index()] == c.Node()  if c.Index() >= 0
+//	p.f            == c.Node()  if c.Index() <  0
+//	p.f[c.Index()] == c.Node()  if c.Index() >= 0
 //
 // The methods Replace, Delete, InsertBefore, and InsertAfter
 // can be used to change the AST without disrupting Apply.
@@ -294,6 +293,9 @@ func (a *application) apply(parent ast.Node, name string, iter *iterator, n ast.
 		a.apply(n, "Fields", nil, n.Fields)
 
 	case *ast.FuncType:
+		if tparams := typeparams.ForFuncType(n); tparams != nil {
+			a.apply(n, "TypeParams", nil, tparams)
+		}
 		a.apply(n, "Params", nil, n.Params)
 		a.apply(n, "Results", nil, n.Results)
 
@@ -406,6 +408,9 @@ func (a *application) apply(parent ast.Node, name string, iter *iterator, n ast.
 	case *ast.TypeSpec:
 		a.apply(n, "Doc", nil, n.Doc)
 		a.apply(n, "Name", nil, n.Name)
+		if tparams := typeparams.ForTypeSpec(n); tparams != nil {
+			a.apply(n, "TypeParams", nil, tparams)
+		}
 		a.apply(n, "Type", nil, n.Type)
 		a.apply(n, "Comment", nil, n.Comment)
 

vendor/golang.org/x/tools/go/ast/inspector/typeof.go

@@ -77,12 +77,14 @@ const (
 // typeOf returns a distinct single-bit value that represents the type of n.
 //
 // Various implementations were benchmarked with BenchmarkNewInspector:
-//								GOGC=off
-// - type switch				4.9-5.5ms	2.1ms
-// - binary search over a sorted list of types  5.5-5.9ms	2.5ms
-// - linear scan, frequency-ordered list 	5.9-6.1ms	2.7ms
-// - linear scan, unordered list		6.4ms		2.7ms
-// - hash table					6.5ms		3.1ms
+//
+//	                                                                GOGC=off
+//	- type switch					4.9-5.5ms	2.1ms
+//	- binary search over a sorted list of types	5.5-5.9ms	2.5ms
+//	- linear scan, frequency-ordered list		5.9-6.1ms	2.7ms
+//	- linear scan, unordered list			6.4ms		2.7ms
+//	- hash table					6.5ms		3.1ms
+//
 // A perfect hash seemed like overkill.
 //
 // The compiler's switch statement is the clear winner
@@ -90,7 +92,6 @@ const (
 // with constant conditions and good branch prediction.
 // (Sadly it is the most verbose in source code.)
 // Binary search suffered from poor branch prediction.
-//
 func typeOf(n ast.Node) uint64 {
 	// Fast path: nearly half of all nodes are identifiers.
 	if _, ok := n.(*ast.Ident); ok {

vendor/golang.org/x/tools/go/gcexportdata/gcexportdata.go

@@ -17,32 +17,47 @@
 // developer tools, which will then be able to consume both Go 1.7 and
 // Go 1.8 export data files, so they will work before and after the
 // Go update. (See discussion at https://golang.org/issue/15651.)
-//
 package gcexportdata // import "golang.org/x/tools/go/gcexportdata"
 
 import (
 	"bufio"
 	"bytes"
+	"encoding/json"
 	"fmt"
 	"go/token"
 	"go/types"
 	"io"
 	"io/ioutil"
+	"os/exec"
 
 	"golang.org/x/tools/go/internal/gcimporter"
 )
 
 // Find returns the name of an object (.o) or archive (.a) file
 // containing type information for the specified import path,
-// using the workspace layout conventions of go/build.
+// using the go command.
 // If no file was found, an empty filename is returned.
 //
 // A relative srcDir is interpreted relative to the current working directory.
 //
 // Find also returns the package's resolved (canonical) import path,
 // reflecting the effects of srcDir and vendoring on importPath.
+//
+// Deprecated: Use the higher-level API in golang.org/x/tools/go/packages,
+// which is more efficient.
 func Find(importPath, srcDir string) (filename, path string) {
-	return gcimporter.FindPkg(importPath, srcDir)
+	cmd := exec.Command("go", "list", "-json", "-export", "--", importPath)
+	cmd.Dir = srcDir
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		return "", ""
+	}
+	var data struct {
+		ImportPath string
+		Export     string
+	}
+	json.Unmarshal(out, &data)
+	return data.Export, data.ImportPath
 }
 
 // NewReader returns a reader for the export data section of an object
@@ -101,13 +116,29 @@ func Read(in io.Reader, fset *token.FileSet, imports map[string]*types.Package,
 	// The indexed export format starts with an 'i'; the older
 	// binary export format starts with a 'c', 'd', or 'v'
 	// (from "version"). Select appropriate importer.
-	if len(data) > 0 && data[0] == 'i' {
-		_, pkg, err := gcimporter.IImportData(fset, imports, data[1:], path)
-		return pkg, err
-	}
+	if len(data) > 0 {
+		switch data[0] {
+		case 'i':
+			_, pkg, err := gcimporter.IImportData(fset, imports, data[1:], path)
+			return pkg, err
 
-	_, pkg, err := gcimporter.BImportData(fset, imports, data, path)
-	return pkg, err
+		case 'v', 'c', 'd':
+			_, pkg, err := gcimporter.BImportData(fset, imports, data, path)
+			return pkg, err
+
+		case 'u':
+			_, pkg, err := gcimporter.UImportData(fset, imports, data[1:], path)
+			return pkg, err
+
+		default:
+			l := len(data)
+			if l > 10 {
+				l = 10
+			}
+			return nil, fmt.Errorf("unexpected export data with prefix %q for path %s", string(data[:l]), path)
+		}
+	}
+	return nil, fmt.Errorf("empty export data for %s", path)
 }
 
 // Write writes encoded type information for the specified package to out.

vendor/golang.org/x/tools/go/gcexportdata/importer.go

@@ -23,6 +23,8 @@ import (
 // or to control the FileSet or access the imports map populated during
 // package loading.
 //
+// Deprecated: Use the higher-level API in golang.org/x/tools/go/packages,
+// which is more efficient.
 func NewImporter(fset *token.FileSet, imports map[string]*types.Package) types.ImporterFrom {
 	return importer{fset, imports}
 }

vendor/golang.org/x/tools/go/internal/gcimporter/bexport.go

@@ -35,16 +35,18 @@ import (
 const debugFormat = false // default: false
 
 // Current export format version. Increase with each format change.
+//
 // Note: The latest binary (non-indexed) export format is at version 6.
-//       This exporter is still at level 4, but it doesn't matter since
-//       the binary importer can handle older versions just fine.
-// 6: package height (CL 105038) -- NOT IMPLEMENTED HERE
-// 5: improved position encoding efficiency (issue 20080, CL 41619) -- NOT IMPLEMEMTED HERE
-// 4: type name objects support type aliases, uses aliasTag
-// 3: Go1.8 encoding (same as version 2, aliasTag defined but never used)
-// 2: removed unused bool in ODCL export (compiler only)
-// 1: header format change (more regular), export package for _ struct fields
-// 0: Go1.7 encoding
+// This exporter is still at level 4, but it doesn't matter since
+// the binary importer can handle older versions just fine.
+//
+//	6: package height (CL 105038) -- NOT IMPLEMENTED HERE
+//	5: improved position encoding efficiency (issue 20080, CL 41619) -- NOT IMPLEMENTED HERE
+//	4: type name objects support type aliases, uses aliasTag
+//	3: Go1.8 encoding (same as version 2, aliasTag defined but never used)
+//	2: removed unused bool in ODCL export (compiler only)
+//	1: header format change (more regular), export package for _ struct fields
+//	0: Go1.7 encoding
 const exportVersion = 4
 
 // trackAllTypes enables cycle tracking for all types, not just named

vendor/golang.org/x/tools/go/internal/gcimporter/gcimporter.go

@@ -45,7 +45,6 @@ var pkgExts = [...]string{".a", ".o"}
 // the build.Default build.Context). A relative srcDir is interpreted
 // relative to the current working directory.
 // If no file was found, an empty filename is returned.
-//
 func FindPkg(path, srcDir string) (filename, id string) {
 	if path == "" {
 		return
@@ -109,7 +108,6 @@ func FindPkg(path, srcDir string) (filename, id string) {
 // If packages[id] contains the completely imported package, that package
 // can be used directly, and there is no need to call this function (but
 // there is also no harm but for extra time used).
-//
 func ImportData(packages map[string]*types.Package, filename, id string, data io.Reader) (pkg *types.Package, err error) {
 	// support for parser error handling
 	defer func() {
@@ -133,7 +131,6 @@ func ImportData(packages map[string]*types.Package, filename, id string, data io
 // Import imports a gc-generated package given its import path and srcDir, adds
 // the corresponding package object to the packages map, and returns the object.
 // The packages map must contain all packages already imported.
-//
 func Import(packages map[string]*types.Package, path, srcDir string, lookup func(path string) (io.ReadCloser, error)) (pkg *types.Package, err error) {
 	var rc io.ReadCloser
 	var filename, id string
@@ -184,8 +181,9 @@ func Import(packages map[string]*types.Package, path, srcDir string, lookup func
 	defer rc.Close()
 
 	var hdr string
+	var size int64
 	buf := bufio.NewReader(rc)
-	if hdr, _, err = FindExportData(buf); err != nil {
+	if hdr, size, err = FindExportData(buf); err != nil {
 		return
 	}
 
@@ -213,10 +211,27 @@ func Import(packages map[string]*types.Package, path, srcDir string, lookup func
 		// The indexed export format starts with an 'i'; the older
 		// binary export format starts with a 'c', 'd', or 'v'
 		// (from "version"). Select appropriate importer.
-		if len(data) > 0 && data[0] == 'i' {
-			_, pkg, err = IImportData(fset, packages, data[1:], id)
-		} else {
-			_, pkg, err = BImportData(fset, packages, data, id)
+		if len(data) > 0 {
+			switch data[0] {
+			case 'i':
+				_, pkg, err := IImportData(fset, packages, data[1:], id)
+				return pkg, err
+
+			case 'v', 'c', 'd':
+				_, pkg, err := BImportData(fset, packages, data, id)
+				return pkg, err
+
+			case 'u':
+				_, pkg, err := UImportData(fset, packages, data[1:size], id)
+				return pkg, err
+
+			default:
+				l := len(data)
+				if l > 10 {
+					l = 10
+				}
+				return nil, fmt.Errorf("unexpected export data with prefix %q for path %s", string(data[:l]), id)
+			}
 		}
 
 	default:
@@ -348,8 +363,9 @@ func (p *parser) expectKeyword(keyword string) {
 // ----------------------------------------------------------------------------
 // Qualified and unqualified names
 
-// PackageId = string_lit .
+// parsePackageID parses a PackageId:
 //
+//	PackageId = string_lit .
 func (p *parser) parsePackageID() string {
 	id, err := strconv.Unquote(p.expect(scanner.String))
 	if err != nil {
@@ -363,13 +379,16 @@ func (p *parser) parsePackageID() string {
 	return id
 }
 
-// PackageName = ident .
+// parsePackageName parse a PackageName:
 //
+//	PackageName = ident .
 func (p *parser) parsePackageName() string {
 	return p.expect(scanner.Ident)
 }
 
-// dotIdentifier = ( ident | '·' ) { ident | int | '·' } .
+// parseDotIdent parses a dotIdentifier:
+//
+//	dotIdentifier = ( ident | '·' ) { ident | int | '·' } .
 func (p *parser) parseDotIdent() string {
 	ident := ""
 	if p.tok != scanner.Int {
@@ -386,8 +405,9 @@ func (p *parser) parseDotIdent() string {
 	return ident
 }
 
-// QualifiedName = "@" PackageId "." ( "?" | dotIdentifier ) .
+// parseQualifiedName parses a QualifiedName:
 //
+//	QualifiedName = "@" PackageId "." ( "?" | dotIdentifier ) .
 func (p *parser) parseQualifiedName() (id, name string) {
 	p.expect('@')
 	id = p.parsePackageID()
@@ -410,7 +430,6 @@ func (p *parser) parseQualifiedName() (id, name string) {
 // id identifies a package, usually by a canonical package path like
 // "encoding/json" but possibly by a non-canonical import path like
 // "./json".
-//
 func (p *parser) getPkg(id, name string) *types.Package {
 	// package unsafe is not in the packages maps - handle explicitly
 	if id == "unsafe" {
@@ -446,7 +465,6 @@ func (p *parser) getPkg(id, name string) *types.Package {
 
 // parseExportedName is like parseQualifiedName, but
 // the package id is resolved to an imported *types.Package.
-//
 func (p *parser) parseExportedName() (pkg *types.Package, name string) {
 	id, name := p.parseQualifiedName()
 	pkg = p.getPkg(id, "")
@@ -456,8 +474,9 @@ func (p *parser) parseExportedName() (pkg *types.Package, name string) {
 // ----------------------------------------------------------------------------
 // Types
 
-// BasicType = identifier .
+// parseBasicType parses a BasicType:
 //
+//	BasicType = identifier .
 func (p *parser) parseBasicType() types.Type {
 	id := p.expect(scanner.Ident)
 	obj := types.Universe.Lookup(id)
@@ -468,8 +487,9 @@ func (p *parser) parseBasicType() types.Type {
 	return nil
 }
 
-// ArrayType = "[" int_lit "]" Type .
+// parseArrayType parses an ArrayType:
 //
+//	ArrayType = "[" int_lit "]" Type .
 func (p *parser) parseArrayType(parent *types.Package) types.Type {
 	// "[" already consumed and lookahead known not to be "]"
 	lit := p.expect(scanner.Int)
@@ -482,8 +502,9 @@ func (p *parser) parseArrayType(parent *types.Package) types.Type {
 	return types.NewArray(elem, n)
 }
 
-// MapType = "map" "[" Type "]" Type .
+// parseMapType parses a MapType:
 //
+//	MapType = "map" "[" Type "]" Type .
 func (p *parser) parseMapType(parent *types.Package) types.Type {
 	p.expectKeyword("map")
 	p.expect('[')
@@ -493,7 +514,9 @@ func (p *parser) parseMapType(parent *types.Package) types.Type {
 	return types.NewMap(key, elem)
 }
 
-// Name = identifier | "?" | QualifiedName .
+// parseName parses a Name:
+//
+//	Name = identifier | "?" | QualifiedName .
 //
 // For unqualified and anonymous names, the returned package is the parent
 // package unless parent == nil, in which case the returned package is the
@@ -505,7 +528,6 @@ func (p *parser) parseMapType(parent *types.Package) types.Type {
 // it doesn't exist yet) unless materializePkg is set (which creates an
 // unnamed package with valid package path). In the latter case, a
 // subsequent import clause is expected to provide a name for the package.
-//
 func (p *parser) parseName(parent *types.Package, materializePkg bool) (pkg *types.Package, name string) {
 	pkg = parent
 	if pkg == nil {
@@ -539,8 +561,9 @@ func deref(typ types.Type) types.Type {
 	return typ
 }
 
-// Field = Name Type [ string_lit ] .
+// parseField parses a Field:
 //
+//	Field = Name Type [ string_lit ] .
 func (p *parser) parseField(parent *types.Package) (*types.Var, string) {
 	pkg, name := p.parseName(parent, true)
 
@@ -583,9 +606,10 @@ func (p *parser) parseField(parent *types.Package) (*types.Var, string) {
 	return types.NewField(token.NoPos, pkg, name, typ, anonymous), tag
 }
 
-// StructType = "struct" "{" [ FieldList ] "}" .
-// FieldList  = Field { ";" Field } .
+// parseStructType parses a StructType:
 //
+//	StructType = "struct" "{" [ FieldList ] "}" .
+//	FieldList  = Field { ";" Field } .
 func (p *parser) parseStructType(parent *types.Package) types.Type {
 	var fields []*types.Var
 	var tags []string
@@ -610,8 +634,9 @@ func (p *parser) parseStructType(parent *types.Package) types.Type {
 	return types.NewStruct(fields, tags)
 }
 
-// Parameter = ( identifier | "?" ) [ "..." ] Type [ string_lit ] .
+// parseParameter parses a Parameter:
 //
+//	Parameter = ( identifier | "?" ) [ "..." ] Type [ string_lit ] .
 func (p *parser) parseParameter() (par *types.Var, isVariadic bool) {
 	_, name := p.parseName(nil, false)
 	// remove gc-specific parameter numbering
@@ -635,9 +660,10 @@ func (p *parser) parseParameter() (par *types.Var, isVariadic bool) {
 	return
 }
 
-// Parameters    = "(" [ ParameterList ] ")" .
-// ParameterList = { Parameter "," } Parameter .
+// parseParameters parses a Parameters:
 //
+//	Parameters    = "(" [ ParameterList ] ")" .
+//	ParameterList = { Parameter "," } Parameter .
 func (p *parser) parseParameters() (list []*types.Var, isVariadic bool) {
 	p.expect('(')
 	for p.tok != ')' && p.tok != scanner.EOF {
@@ -658,9 +684,10 @@ func (p *parser) parseParameters() (list []*types.Var, isVariadic bool) {
 	return
 }
 
-// Signature = Parameters [ Result ] .
-// Result    = Type | Parameters .
+// parseSignature parses a Signature:
 //
+//	Signature = Parameters [ Result ] .
+//	Result    = Type | Parameters .
 func (p *parser) parseSignature(recv *types.Var) *types.Signature {
 	params, isVariadic := p.parseParameters()
 
@@ -677,14 +704,15 @@ func (p *parser) parseSignature(recv *types.Var) *types.Signature {
 	return types.NewSignature(recv, types.NewTuple(params...), types.NewTuple(results...), isVariadic)
 }
 
-// InterfaceType = "interface" "{" [ MethodList ] "}" .
-// MethodList    = Method { ";" Method } .
-// Method        = Name Signature .
+// parseInterfaceType parses an InterfaceType:
+//
+//	InterfaceType = "interface" "{" [ MethodList ] "}" .
+//	MethodList    = Method { ";" Method } .
+//	Method        = Name Signature .
 //
 // The methods of embedded interfaces are always "inlined"
 // by the compiler and thus embedded interfaces are never
 // visible in the export data.
-//
 func (p *parser) parseInterfaceType(parent *types.Package) types.Type {
 	var methods []*types.Func
 
@@ -705,8 +733,9 @@ func (p *parser) parseInterfaceType(parent *types.Package) types.Type {
 	return newInterface(methods, nil).Complete()
 }
 
-// ChanType = ( "chan" [ "<-" ] | "<-" "chan" ) Type .
+// parseChanType parses a ChanType:
 //
+//	ChanType = ( "chan" [ "<-" ] | "<-" "chan" ) Type .
 func (p *parser) parseChanType(parent *types.Package) types.Type {
 	dir := types.SendRecv
 	if p.tok == scanner.Ident {
@@ -724,17 +753,18 @@ func (p *parser) parseChanType(parent *types.Package) types.Type {
 	return types.NewChan(dir, elem)
 }
 
-// Type =
-//	BasicType | TypeName | ArrayType | SliceType | StructType |
-//      PointerType | FuncType | InterfaceType | MapType | ChanType |
-//      "(" Type ")" .
+// parseType parses a Type:
 //
-// BasicType   = ident .
-// TypeName    = ExportedName .
-// SliceType   = "[" "]" Type .
-// PointerType = "*" Type .
-// FuncType    = "func" Signature .
+//	Type =
+//		BasicType | TypeName | ArrayType | SliceType | StructType |
+//		PointerType | FuncType | InterfaceType | MapType | ChanType |
+//		"(" Type ")" .
 //
+//	BasicType   = ident .
+//	TypeName    = ExportedName .
+//	SliceType   = "[" "]" Type .
+//	PointerType = "*" Type .
+//	FuncType    = "func" Signature .
 func (p *parser) parseType(parent *types.Package) types.Type {
 	switch p.tok {
 	case scanner.Ident:
@@ -786,16 +816,18 @@ func (p *parser) parseType(parent *types.Package) types.Type {
 // ----------------------------------------------------------------------------
 // Declarations
 
-// ImportDecl = "import" PackageName PackageId .
+// parseImportDecl parses an ImportDecl:
 //
+//	ImportDecl = "import" PackageName PackageId .
 func (p *parser) parseImportDecl() {
 	p.expectKeyword("import")
 	name := p.parsePackageName()
 	p.getPkg(p.parsePackageID(), name)
 }
 
-// int_lit = [ "+" | "-" ] { "0" ... "9" } .
+// parseInt parses an int_lit:
 //
+//	int_lit = [ "+" | "-" ] { "0" ... "9" } .
 func (p *parser) parseInt() string {
 	s := ""
 	switch p.tok {
@@ -808,8 +840,9 @@ func (p *parser) parseInt() string {
 	return s + p.expect(scanner.Int)
 }
 
-// number = int_lit [ "p" int_lit ] .
+// parseNumber parses a number:
 //
+//	number = int_lit [ "p" int_lit ] .
 func (p *parser) parseNumber() (typ *types.Basic, val constant.Value) {
 	// mantissa
 	mant := constant.MakeFromLiteral(p.parseInt(), token.INT, 0)
@@ -844,13 +877,14 @@ func (p *parser) parseNumber() (typ *types.Basic, val constant.Value) {
 	return
 }
 
-// ConstDecl   = "const" ExportedName [ Type ] "=" Literal .
-// Literal     = bool_lit | int_lit | float_lit | complex_lit | rune_lit | string_lit .
-// bool_lit    = "true" | "false" .
-// complex_lit = "(" float_lit "+" float_lit "i" ")" .
-// rune_lit    = "(" int_lit "+" int_lit ")" .
-// string_lit  = `"` { unicode_char } `"` .
+// parseConstDecl parses a ConstDecl:
 //
+//	ConstDecl   = "const" ExportedName [ Type ] "=" Literal .
+//	Literal     = bool_lit | int_lit | float_lit | complex_lit | rune_lit | string_lit .
+//	bool_lit    = "true" | "false" .
+//	complex_lit = "(" float_lit "+" float_lit "i" ")" .
+//	rune_lit    = "(" int_lit "+" int_lit ")" .
+//	string_lit  = `"` { unicode_char } `"` .
 func (p *parser) parseConstDecl() {
 	p.expectKeyword("const")
 	pkg, name := p.parseExportedName()
@@ -920,8 +954,9 @@ func (p *parser) parseConstDecl() {
 	pkg.Scope().Insert(types.NewConst(token.NoPos, pkg, name, typ0, val))
 }
 
-// TypeDecl = "type" ExportedName Type .
+// parseTypeDecl parses a TypeDecl:
 //
+//	TypeDecl = "type" ExportedName Type .
 func (p *parser) parseTypeDecl() {
 	p.expectKeyword("type")
 	pkg, name := p.parseExportedName()
@@ -939,8 +974,9 @@ func (p *parser) parseTypeDecl() {
 	}
 }
 
-// VarDecl = "var" ExportedName Type .
+// parseVarDecl parses a VarDecl:
 //
+//	VarDecl = "var" ExportedName Type .
 func (p *parser) parseVarDecl() {
 	p.expectKeyword("var")
 	pkg, name := p.parseExportedName()
@@ -948,9 +984,10 @@ func (p *parser) parseVarDecl() {
 	pkg.Scope().Insert(types.NewVar(token.NoPos, pkg, name, typ))
 }
 
-// Func = Signature [ Body ] .
-// Body = "{" ... "}" .
+// parseFunc parses a Func:
 //
+//	Func = Signature [ Body ] .
+//	Body = "{" ... "}" .
 func (p *parser) parseFunc(recv *types.Var) *types.Signature {
 	sig := p.parseSignature(recv)
 	if p.tok == '{' {
@@ -967,9 +1004,10 @@ func (p *parser) parseFunc(recv *types.Var) *types.Signature {
 	return sig
 }
 
-// MethodDecl = "func" Receiver Name Func .
-// Receiver   = "(" ( identifier | "?" ) [ "*" ] ExportedName ")" .
+// parseMethodDecl parses a MethodDecl:
 //
+//	MethodDecl = "func" Receiver Name Func .
+//	Receiver   = "(" ( identifier | "?" ) [ "*" ] ExportedName ")" .
 func (p *parser) parseMethodDecl() {
 	// "func" already consumed
 	p.expect('(')
@@ -992,8 +1030,9 @@ func (p *parser) parseMethodDecl() {
 	base.AddMethod(types.NewFunc(token.NoPos, pkg, name, sig))
 }
 
-// FuncDecl = "func" ExportedName Func .
+// parseFuncDecl parses a FuncDecl:
 //
+//	FuncDecl = "func" ExportedName Func .
 func (p *parser) parseFuncDecl() {
 	// "func" already consumed
 	pkg, name := p.parseExportedName()
@@ -1001,8 +1040,9 @@ func (p *parser) parseFuncDecl() {
 	pkg.Scope().Insert(types.NewFunc(token.NoPos, pkg, name, typ))
 }
 
-// Decl = [ ImportDecl | ConstDecl | TypeDecl | VarDecl | FuncDecl | MethodDecl ] "\n" .
+// parseDecl parses a Decl:
 //
+//	Decl = [ ImportDecl | ConstDecl | TypeDecl | VarDecl | FuncDecl | MethodDecl ] "\n" .
 func (p *parser) parseDecl() {
 	if p.tok == scanner.Ident {
 		switch p.lit {
@@ -1029,9 +1069,10 @@ func (p *parser) parseDecl() {
 // ----------------------------------------------------------------------------
 // Export
 
-// Export        = "PackageClause { Decl } "$$" .
-// PackageClause = "package" PackageName [ "safe" ] "\n" .
+// parseExport parses an Export:
 //
+//	Export        = "PackageClause { Decl } "$$" .
+//	PackageClause = "package" PackageName [ "safe" ] "\n" .
 func (p *parser) parseExport() *types.Package {
 	p.expectKeyword("package")
 	name := p.parsePackageName()

vendor/golang.org/x/tools/go/internal/gcimporter/iexport.go

@@ -251,7 +251,10 @@ func (p *iexporter) stringOff(s string) uint64 {
 // pushDecl adds n to the declaration work queue, if not already present.
 func (p *iexporter) pushDecl(obj types.Object) {
 	// Package unsafe is known to the compiler and predeclared.
-	assert(obj.Pkg() != types.Unsafe)
+	// Caller should not ask us to do export it.
+	if obj.Pkg() == types.Unsafe {
+		panic("cannot export package unsafe")
+	}
 
 	if _, ok := p.declIndex[obj]; ok {
 		return

vendor/golang.org/x/tools/go/internal/gcimporter/iimport.go

@@ -17,6 +17,7 @@ import (
 	"go/token"
 	"go/types"
 	"io"
+	"math/big"
 	"sort"
 	"strings"
 
@@ -53,7 +54,7 @@ const (
 )
 
 type ident struct {
-	pkg  string
+	pkg  *types.Package
 	name string
 }
 
@@ -100,7 +101,9 @@ func iimportCommon(fset *token.FileSet, imports map[string]*types.Package, data
 	if !debug {
 		defer func() {
 			if e := recover(); e != nil {
-				if version > currentVersion {
+				if bundle {
+					err = fmt.Errorf("%v", e)
+				} else if version > currentVersion {
 					err = fmt.Errorf("cannot import %q (%v), export data is newer version - update tool", path, e)
 				} else {
 					err = fmt.Errorf("cannot import %q (%v), possibly version skew - reinstall package", path, e)
@@ -461,7 +464,7 @@ func (r *importReader) obj(name string) {
 
 		// To handle recursive references to the typeparam within its
 		// bound, save the partial type in tparamIndex before reading the bounds.
-		id := ident{r.currPkg.Name(), name}
+		id := ident{r.currPkg, name}
 		r.p.tparamIndex[id] = t
 		var implicit bool
 		if r.p.version >= iexportVersionGo1_18 {
@@ -510,7 +513,9 @@ func (r *importReader) value() (typ types.Type, val constant.Value) {
 		val = constant.MakeString(r.string())
 
 	case types.IsInteger:
-		val = r.mpint(b)
+		var x big.Int
+		r.mpint(&x, b)
+		val = constant.Make(&x)
 
 	case types.IsFloat:
 		val = r.mpfloat(b)
@@ -559,8 +564,8 @@ func intSize(b *types.Basic) (signed bool, maxBytes uint) {
 	return
 }
 
-func (r *importReader) mpint(b *types.Basic) constant.Value {
-	signed, maxBytes := intSize(b)
+func (r *importReader) mpint(x *big.Int, typ *types.Basic) {
+	signed, maxBytes := intSize(typ)
 
 	maxSmall := 256 - maxBytes
 	if signed {
@@ -579,7 +584,8 @@ func (r *importReader) mpint(b *types.Basic) constant.Value {
 				v = ^v
 			}
 		}
-		return constant.MakeInt64(v)
+		x.SetInt64(v)
+		return
 	}
 
 	v := -n
@@ -589,47 +595,23 @@ func (r *importReader) mpint(b *types.Basic) constant.Value {
 	if v < 1 || uint(v) > maxBytes {
 		errorf("weird decoding: %v, %v => %v", n, signed, v)
 	}
-
-	buf := make([]byte, v)
-	io.ReadFull(&r.declReader, buf)
-
-	// convert to little endian
-	// TODO(gri) go/constant should have a more direct conversion function
-	//           (e.g., once it supports a big.Float based implementation)
-	for i, j := 0, len(buf)-1; i < j; i, j = i+1, j-1 {
-		buf[i], buf[j] = buf[j], buf[i]
-	}
-
-	x := constant.MakeFromBytes(buf)
+	b := make([]byte, v)
+	io.ReadFull(&r.declReader, b)
+	x.SetBytes(b)
 	if signed && n&1 != 0 {
-		x = constant.UnaryOp(token.SUB, x, 0)
+		x.Neg(x)
 	}
-	return x
 }
 
-func (r *importReader) mpfloat(b *types.Basic) constant.Value {
-	x := r.mpint(b)
-	if constant.Sign(x) == 0 {
-		return x
+func (r *importReader) mpfloat(typ *types.Basic) constant.Value {
+	var mant big.Int
+	r.mpint(&mant, typ)
+	var f big.Float
+	f.SetInt(&mant)
+	if f.Sign() != 0 {
+		f.SetMantExp(&f, int(r.int64()))
 	}
-
-	exp := r.int64()
-	switch {
-	case exp > 0:
-		x = constant.Shift(x, token.SHL, uint(exp))
-		// Ensure that the imported Kind is Float, else this constant may run into
-		// bitsize limits on overlarge integers. Eventually we can instead adopt
-		// the approach of CL 288632, but that CL relies on go/constant APIs that
-		// were introduced in go1.13.
-		//
-		// TODO(rFindley): sync the logic here with tip Go once we no longer
-		// support go1.12.
-		x = constant.ToFloat(x)
-	case exp < 0:
-		d := constant.Shift(constant.MakeInt64(1), token.SHL, uint(-exp))
-		x = constant.BinaryOp(x, token.QUO, d)
-	}
-	return x
+	return constant.Make(&f)
 }
 
 func (r *importReader) ident() string {
@@ -777,7 +759,7 @@ func (r *importReader) doType(base *types.Named) (res types.Type) {
 			errorf("unexpected type param type")
 		}
 		pkg, name := r.qualifiedIdent()
-		id := ident{pkg.Name(), name}
+		id := ident{pkg, name}
 		if t, ok := r.p.tparamIndex[id]; ok {
 			// We're already in the process of importing this typeparam.
 			return t

vendor/golang.org/x/tools/go/internal/gcimporter/unified_no.go

@@ -0,0 +1,10 @@
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build !(go1.18 && goexperiment.unified)
+// +build !go1.18 !goexperiment.unified
+
+package gcimporter
+
+const unifiedIR = false

vendor/golang.org/x/tools/go/internal/gcimporter/unified_yes.go

@@ -0,0 +1,10 @@
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build go1.18 && goexperiment.unified
+// +build go1.18,goexperiment.unified
+
+package gcimporter
+
+const unifiedIR = true

vendor/golang.org/x/tools/go/internal/gcimporter/ureader_no.go

@@ -0,0 +1,19 @@
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build !go1.18
+// +build !go1.18
+
+package gcimporter
+
+import (
+	"fmt"
+	"go/token"
+	"go/types"
+)
+
+func UImportData(fset *token.FileSet, imports map[string]*types.Package, data []byte, path string) (_ int, pkg *types.Package, err error) {
+	err = fmt.Errorf("go/tools compiled with a Go version earlier than 1.18 cannot read unified IR export data")
+	return
+}

vendor/golang.org/x/tools/go/internal/gcimporter/ureader_yes.go

@@ -0,0 +1,612 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Derived from go/internal/gcimporter/ureader.go
+
+//go:build go1.18
+// +build go1.18
+
+package gcimporter
+
+import (
+	"go/token"
+	"go/types"
+	"strings"
+
+	"golang.org/x/tools/go/internal/pkgbits"
+)
+
+// A pkgReader holds the shared state for reading a unified IR package
+// description.
+type pkgReader struct {
+	pkgbits.PkgDecoder
+
+	fake fakeFileSet
+
+	ctxt    *types.Context
+	imports map[string]*types.Package // previously imported packages, indexed by path
+
+	// lazily initialized arrays corresponding to the unified IR
+	// PosBase, Pkg, and Type sections, respectively.
+	posBases []string // position bases (i.e., file names)
+	pkgs     []*types.Package
+	typs     []types.Type
+
+	// laterFns holds functions that need to be invoked at the end of
+	// import reading.
+	laterFns []func()
+}
+
+// later adds a function to be invoked at the end of import reading.
+func (pr *pkgReader) later(fn func()) {
+	pr.laterFns = append(pr.laterFns, fn)
+}
+
+// See cmd/compile/internal/noder.derivedInfo.
+type derivedInfo struct {
+	idx    pkgbits.Index
+	needed bool
+}
+
+// See cmd/compile/internal/noder.typeInfo.
+type typeInfo struct {
+	idx     pkgbits.Index
+	derived bool
+}
+
+func UImportData(fset *token.FileSet, imports map[string]*types.Package, data []byte, path string) (_ int, pkg *types.Package, err error) {
+	s := string(data)
+	s = s[:strings.LastIndex(s, "\n$$\n")]
+	input := pkgbits.NewPkgDecoder(path, s)
+	pkg = readUnifiedPackage(fset, nil, imports, input)
+	return
+}
+
+// readUnifiedPackage reads a package description from the given
+// unified IR export data decoder.
+func readUnifiedPackage(fset *token.FileSet, ctxt *types.Context, imports map[string]*types.Package, input pkgbits.PkgDecoder) *types.Package {
+	pr := pkgReader{
+		PkgDecoder: input,
+
+		fake: fakeFileSet{
+			fset:  fset,
+			files: make(map[string]*fileInfo),
+		},
+
+		ctxt:    ctxt,
+		imports: imports,
+
+		posBases: make([]string, input.NumElems(pkgbits.RelocPosBase)),
+		pkgs:     make([]*types.Package, input.NumElems(pkgbits.RelocPkg)),
+		typs:     make([]types.Type, input.NumElems(pkgbits.RelocType)),
+	}
+	defer pr.fake.setLines()
+
+	r := pr.newReader(pkgbits.RelocMeta, pkgbits.PublicRootIdx, pkgbits.SyncPublic)
+	pkg := r.pkg()
+	r.Bool() // has init
+
+	for i, n := 0, r.Len(); i < n; i++ {
+		// As if r.obj(), but avoiding the Scope.Lookup call,
+		// to avoid eager loading of imports.
+		r.Sync(pkgbits.SyncObject)
+		assert(!r.Bool())
+		r.p.objIdx(r.Reloc(pkgbits.RelocObj))
+		assert(r.Len() == 0)
+	}
+
+	r.Sync(pkgbits.SyncEOF)
+
+	for _, fn := range pr.laterFns {
+		fn()
+	}
+
+	pkg.MarkComplete()
+	return pkg
+}
+
+// A reader holds the state for reading a single unified IR element
+// within a package.
+type reader struct {
+	pkgbits.Decoder
+
+	p *pkgReader
+
+	dict *readerDict
+}
+
+// A readerDict holds the state for type parameters that parameterize
+// the current unified IR element.
+type readerDict struct {
+	// bounds is a slice of typeInfos corresponding to the underlying
+	// bounds of the element's type parameters.
+	bounds []typeInfo
+
+	// tparams is a slice of the constructed TypeParams for the element.
+	tparams []*types.TypeParam
+
+	// devived is a slice of types derived from tparams, which may be
+	// instantiated while reading the current element.
+	derived      []derivedInfo
+	derivedTypes []types.Type // lazily instantiated from derived
+}
+
+func (pr *pkgReader) newReader(k pkgbits.RelocKind, idx pkgbits.Index, marker pkgbits.SyncMarker) *reader {
+	return &reader{
+		Decoder: pr.NewDecoder(k, idx, marker),
+		p:       pr,
+	}
+}
+
+// @@@ Positions
+
+func (r *reader) pos() token.Pos {
+	r.Sync(pkgbits.SyncPos)
+	if !r.Bool() {
+		return token.NoPos
+	}
+
+	// TODO(mdempsky): Delta encoding.
+	posBase := r.posBase()
+	line := r.Uint()
+	col := r.Uint()
+	return r.p.fake.pos(posBase, int(line), int(col))
+}
+
+func (r *reader) posBase() string {
+	return r.p.posBaseIdx(r.Reloc(pkgbits.RelocPosBase))
+}
+
+func (pr *pkgReader) posBaseIdx(idx pkgbits.Index) string {
+	if b := pr.posBases[idx]; b != "" {
+		return b
+	}
+
+	r := pr.newReader(pkgbits.RelocPosBase, idx, pkgbits.SyncPosBase)
+
+	// Within types2, position bases have a lot more details (e.g.,
+	// keeping track of where //line directives appeared exactly).
+	//
+	// For go/types, we just track the file name.
+
+	filename := r.String()
+
+	if r.Bool() { // file base
+		// Was: "b = token.NewTrimmedFileBase(filename, true)"
+	} else { // line base
+		pos := r.pos()
+		line := r.Uint()
+		col := r.Uint()
+
+		// Was: "b = token.NewLineBase(pos, filename, true, line, col)"
+		_, _, _ = pos, line, col
+	}
+
+	b := filename
+	pr.posBases[idx] = b
+	return b
+}
+
+// @@@ Packages
+
+func (r *reader) pkg() *types.Package {
+	r.Sync(pkgbits.SyncPkg)
+	return r.p.pkgIdx(r.Reloc(pkgbits.RelocPkg))
+}
+
+func (pr *pkgReader) pkgIdx(idx pkgbits.Index) *types.Package {
+	// TODO(mdempsky): Consider using some non-nil pointer to indicate
+	// the universe scope, so we don't need to keep re-reading it.
+	if pkg := pr.pkgs[idx]; pkg != nil {
+		return pkg
+	}
+
+	pkg := pr.newReader(pkgbits.RelocPkg, idx, pkgbits.SyncPkgDef).doPkg()
+	pr.pkgs[idx] = pkg
+	return pkg
+}
+
+func (r *reader) doPkg() *types.Package {
+	path := r.String()
+	switch path {
+	case "":
+		path = r.p.PkgPath()
+	case "builtin":
+		return nil // universe
+	case "unsafe":
+		return types.Unsafe
+	}
+
+	if pkg := r.p.imports[path]; pkg != nil {
+		return pkg
+	}
+
+	name := r.String()
+
+	pkg := types.NewPackage(path, name)
+	r.p.imports[path] = pkg
+
+	imports := make([]*types.Package, r.Len())
+	for i := range imports {
+		imports[i] = r.pkg()
+	}
+	pkg.SetImports(imports)
+
+	return pkg
+}
+
+// @@@ Types
+
+func (r *reader) typ() types.Type {
+	return r.p.typIdx(r.typInfo(), r.dict)
+}
+
+func (r *reader) typInfo() typeInfo {
+	r.Sync(pkgbits.SyncType)
+	if r.Bool() {
+		return typeInfo{idx: pkgbits.Index(r.Len()), derived: true}
+	}
+	return typeInfo{idx: r.Reloc(pkgbits.RelocType), derived: false}
+}
+
+func (pr *pkgReader) typIdx(info typeInfo, dict *readerDict) types.Type {
+	idx := info.idx
+	var where *types.Type
+	if info.derived {
+		where = &dict.derivedTypes[idx]
+		idx = dict.derived[idx].idx
+	} else {
+		where = &pr.typs[idx]
+	}
+
+	if typ := *where; typ != nil {
+		return typ
+	}
+
+	r := pr.newReader(pkgbits.RelocType, idx, pkgbits.SyncTypeIdx)
+	r.dict = dict
+
+	typ := r.doTyp()
+	assert(typ != nil)
+
+	// See comment in pkgReader.typIdx explaining how this happens.
+	if prev := *where; prev != nil {
+		return prev
+	}
+
+	*where = typ
+	return typ
+}
+
+func (r *reader) doTyp() (res types.Type) {
+	switch tag := pkgbits.CodeType(r.Code(pkgbits.SyncType)); tag {
+	default:
+		errorf("unhandled type tag: %v", tag)
+		panic("unreachable")
+
+	case pkgbits.TypeBasic:
+		return types.Typ[r.Len()]
+
+	case pkgbits.TypeNamed:
+		obj, targs := r.obj()
+		name := obj.(*types.TypeName)
+		if len(targs) != 0 {
+			t, _ := types.Instantiate(r.p.ctxt, name.Type(), targs, false)
+			return t
+		}
+		return name.Type()
+
+	case pkgbits.TypeTypeParam:
+		return r.dict.tparams[r.Len()]
+
+	case pkgbits.TypeArray:
+		len := int64(r.Uint64())
+		return types.NewArray(r.typ(), len)
+	case pkgbits.TypeChan:
+		dir := types.ChanDir(r.Len())
+		return types.NewChan(dir, r.typ())
+	case pkgbits.TypeMap:
+		return types.NewMap(r.typ(), r.typ())
+	case pkgbits.TypePointer:
+		return types.NewPointer(r.typ())
+	case pkgbits.TypeSignature:
+		return r.signature(nil, nil, nil)
+	case pkgbits.TypeSlice:
+		return types.NewSlice(r.typ())
+	case pkgbits.TypeStruct:
+		return r.structType()
+	case pkgbits.TypeInterface:
+		return r.interfaceType()
+	case pkgbits.TypeUnion:
+		return r.unionType()
+	}
+}
+
+func (r *reader) structType() *types.Struct {
+	fields := make([]*types.Var, r.Len())
+	var tags []string
+	for i := range fields {
+		pos := r.pos()
+		pkg, name := r.selector()
+		ftyp := r.typ()
+		tag := r.String()
+		embedded := r.Bool()
+
+		fields[i] = types.NewField(pos, pkg, name, ftyp, embedded)
+		if tag != "" {
+			for len(tags) < i {
+				tags = append(tags, "")
+			}
+			tags = append(tags, tag)
+		}
+	}
+	return types.NewStruct(fields, tags)
+}
+
+func (r *reader) unionType() *types.Union {
+	terms := make([]*types.Term, r.Len())
+	for i := range terms {
+		terms[i] = types.NewTerm(r.Bool(), r.typ())
+	}
+	return types.NewUnion(terms)
+}
+
+func (r *reader) interfaceType() *types.Interface {
+	methods := make([]*types.Func, r.Len())
+	embeddeds := make([]types.Type, r.Len())
+	implicit := len(methods) == 0 && len(embeddeds) == 1 && r.Bool()
+
+	for i := range methods {
+		pos := r.pos()
+		pkg, name := r.selector()
+		mtyp := r.signature(nil, nil, nil)
+		methods[i] = types.NewFunc(pos, pkg, name, mtyp)
+	}
+
+	for i := range embeddeds {
+		embeddeds[i] = r.typ()
+	}
+
+	iface := types.NewInterfaceType(methods, embeddeds)
+	if implicit {
+		iface.MarkImplicit()
+	}
+	return iface
+}
+
+func (r *reader) signature(recv *types.Var, rtparams, tparams []*types.TypeParam) *types.Signature {
+	r.Sync(pkgbits.SyncSignature)
+
+	params := r.params()
+	results := r.params()
+	variadic := r.Bool()
+
+	return types.NewSignatureType(recv, rtparams, tparams, params, results, variadic)
+}
+
+func (r *reader) params() *types.Tuple {
+	r.Sync(pkgbits.SyncParams)
+
+	params := make([]*types.Var, r.Len())
+	for i := range params {
+		params[i] = r.param()
+	}
+
+	return types.NewTuple(params...)
+}
+
+func (r *reader) param() *types.Var {
+	r.Sync(pkgbits.SyncParam)
+
+	pos := r.pos()
+	pkg, name := r.localIdent()
+	typ := r.typ()
+
+	return types.NewParam(pos, pkg, name, typ)
+}
+
+// @@@ Objects
+
+func (r *reader) obj() (types.Object, []types.Type) {
+	r.Sync(pkgbits.SyncObject)
+
+	assert(!r.Bool())
+
+	pkg, name := r.p.objIdx(r.Reloc(pkgbits.RelocObj))
+	obj := pkgScope(pkg).Lookup(name)
+
+	targs := make([]types.Type, r.Len())
+	for i := range targs {
+		targs[i] = r.typ()
+	}
+
+	return obj, targs
+}
+
+func (pr *pkgReader) objIdx(idx pkgbits.Index) (*types.Package, string) {
+	rname := pr.newReader(pkgbits.RelocName, idx, pkgbits.SyncObject1)
+
+	objPkg, objName := rname.qualifiedIdent()
+	assert(objName != "")
+
+	tag := pkgbits.CodeObj(rname.Code(pkgbits.SyncCodeObj))
+
+	if tag == pkgbits.ObjStub {
+		assert(objPkg == nil || objPkg == types.Unsafe)
+		return objPkg, objName
+	}
+
+	if objPkg.Scope().Lookup(objName) == nil {
+		dict := pr.objDictIdx(idx)
+
+		r := pr.newReader(pkgbits.RelocObj, idx, pkgbits.SyncObject1)
+		r.dict = dict
+
+		declare := func(obj types.Object) {
+			objPkg.Scope().Insert(obj)
+		}
+
+		switch tag {
+		default:
+			panic("weird")
+
+		case pkgbits.ObjAlias:
+			pos := r.pos()
+			typ := r.typ()
+			declare(types.NewTypeName(pos, objPkg, objName, typ))
+
+		case pkgbits.ObjConst:
+			pos := r.pos()
+			typ := r.typ()
+			val := r.Value()
+			declare(types.NewConst(pos, objPkg, objName, typ, val))
+
+		case pkgbits.ObjFunc:
+			pos := r.pos()
+			tparams := r.typeParamNames()
+			sig := r.signature(nil, nil, tparams)
+			declare(types.NewFunc(pos, objPkg, objName, sig))
+
+		case pkgbits.ObjType:
+			pos := r.pos()
+
+			obj := types.NewTypeName(pos, objPkg, objName, nil)
+			named := types.NewNamed(obj, nil, nil)
+			declare(obj)
+
+			named.SetTypeParams(r.typeParamNames())
+
+			// TODO(mdempsky): Rewrite receiver types to underlying is an
+			// Interface? The go/types importer does this (I think because
+			// unit tests expected that), but cmd/compile doesn't care
+			// about it, so maybe we can avoid worrying about that here.
+			rhs := r.typ()
+			r.p.later(func() {
+				underlying := rhs.Underlying()
+				named.SetUnderlying(underlying)
+			})
+
+			for i, n := 0, r.Len(); i < n; i++ {
+				named.AddMethod(r.method())
+			}
+
+		case pkgbits.ObjVar:
+			pos := r.pos()
+			typ := r.typ()
+			declare(types.NewVar(pos, objPkg, objName, typ))
+		}
+	}
+
+	return objPkg, objName
+}
+
+func (pr *pkgReader) objDictIdx(idx pkgbits.Index) *readerDict {
+	r := pr.newReader(pkgbits.RelocObjDict, idx, pkgbits.SyncObject1)
+
+	var dict readerDict
+
+	if implicits := r.Len(); implicits != 0 {
+		errorf("unexpected object with %v implicit type parameter(s)", implicits)
+	}
+
+	dict.bounds = make([]typeInfo, r.Len())
+	for i := range dict.bounds {
+		dict.bounds[i] = r.typInfo()
+	}
+
+	dict.derived = make([]derivedInfo, r.Len())
+	dict.derivedTypes = make([]types.Type, len(dict.derived))
+	for i := range dict.derived {
+		dict.derived[i] = derivedInfo{r.Reloc(pkgbits.RelocType), r.Bool()}
+	}
+
+	// function references follow, but reader doesn't need those
+
+	return &dict
+}
+
+func (r *reader) typeParamNames() []*types.TypeParam {
+	r.Sync(pkgbits.SyncTypeParamNames)
+
+	// Note: This code assumes it only processes objects without
+	// implement type parameters. This is currently fine, because
+	// reader is only used to read in exported declarations, which are
+	// always package scoped.
+
+	if len(r.dict.bounds) == 0 {
+		return nil
+	}
+
+	// Careful: Type parameter lists may have cycles. To allow for this,
+	// we construct the type parameter list in two passes: first we
+	// create all the TypeNames and TypeParams, then we construct and
+	// set the bound type.
+
+	r.dict.tparams = make([]*types.TypeParam, len(r.dict.bounds))
+	for i := range r.dict.bounds {
+		pos := r.pos()
+		pkg, name := r.localIdent()
+
+		tname := types.NewTypeName(pos, pkg, name, nil)
+		r.dict.tparams[i] = types.NewTypeParam(tname, nil)
+	}
+
+	typs := make([]types.Type, len(r.dict.bounds))
+	for i, bound := range r.dict.bounds {
+		typs[i] = r.p.typIdx(bound, r.dict)
+	}
+
+	// TODO(mdempsky): This is subtle, elaborate further.
+	//
+	// We have to save tparams outside of the closure, because
+	// typeParamNames() can be called multiple times with the same
+	// dictionary instance.
+	//
+	// Also, this needs to happen later to make sure SetUnderlying has
+	// been called.
+	//
+	// TODO(mdempsky): Is it safe to have a single "later" slice or do
+	// we need to have multiple passes? See comments on CL 386002 and
+	// go.dev/issue/52104.
+	tparams := r.dict.tparams
+	r.p.later(func() {
+		for i, typ := range typs {
+			tparams[i].SetConstraint(typ)
+		}
+	})
+
+	return r.dict.tparams
+}
+
+func (r *reader) method() *types.Func {
+	r.Sync(pkgbits.SyncMethod)
+	pos := r.pos()
+	pkg, name := r.selector()
+
+	rparams := r.typeParamNames()
+	sig := r.signature(r.param(), rparams, nil)
+
+	_ = r.pos() // TODO(mdempsky): Remove; this is a hacker for linker.go.
+	return types.NewFunc(pos, pkg, name, sig)
+}
+
+func (r *reader) qualifiedIdent() (*types.Package, string) { return r.ident(pkgbits.SyncSym) }
+func (r *reader) localIdent() (*types.Package, string)     { return r.ident(pkgbits.SyncLocalIdent) }
+func (r *reader) selector() (*types.Package, string)       { return r.ident(pkgbits.SyncSelector) }
+
+func (r *reader) ident(marker pkgbits.SyncMarker) (*types.Package, string) {
+	r.Sync(marker)
+	return r.pkg(), r.String()
+}
+
+// pkgScope returns pkg.Scope().
+// If pkg is nil, it returns types.Universe instead.
+//
+// TODO(mdempsky): Remove after x/tools can depend on Go 1.19.
+func pkgScope(pkg *types.Package) *types.Scope {
+	if pkg != nil {
+		return pkg.Scope()
+	}
+	return types.Universe
+}

vendor/golang.org/x/tools/go/internal/pkgbits/codes.go

@@ -0,0 +1,77 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package pkgbits
+
+// A Code is an enum value that can be encoded into bitstreams.
+//
+// Code types are preferable for enum types, because they allow
+// Decoder to detect desyncs.
+type Code interface {
+	// Marker returns the SyncMarker for the Code's dynamic type.
+	Marker() SyncMarker
+
+	// Value returns the Code's ordinal value.
+	Value() int
+}
+
+// A CodeVal distinguishes among go/constant.Value encodings.
+type CodeVal int
+
+func (c CodeVal) Marker() SyncMarker { return SyncVal }
+func (c CodeVal) Value() int         { return int(c) }
+
+// Note: These values are public and cannot be changed without
+// updating the go/types importers.
+
+const (
+	ValBool CodeVal = iota
+	ValString
+	ValInt64
+	ValBigInt
+	ValBigRat
+	ValBigFloat
+)
+
+// A CodeType distinguishes among go/types.Type encodings.
+type CodeType int
+
+func (c CodeType) Marker() SyncMarker { return SyncType }
+func (c CodeType) Value() int         { return int(c) }
+
+// Note: These values are public and cannot be changed without
+// updating the go/types importers.
+
+const (
+	TypeBasic CodeType = iota
+	TypeNamed
+	TypePointer
+	TypeSlice
+	TypeArray
+	TypeChan
+	TypeMap
+	TypeSignature
+	TypeStruct
+	TypeInterface
+	TypeUnion
+	TypeTypeParam
+)
+
+// A CodeObj distinguishes among go/types.Object encodings.
+type CodeObj int
+
+func (c CodeObj) Marker() SyncMarker { return SyncCodeObj }
+func (c CodeObj) Value() int         { return int(c) }
+
+// Note: These values are public and cannot be changed without
+// updating the go/types importers.
+
+const (
+	ObjAlias CodeObj = iota
+	ObjConst
+	ObjType
+	ObjFunc
+	ObjVar
+	ObjStub
+)

vendor/golang.org/x/tools/go/internal/pkgbits/decoder.go

@@ -0,0 +1,433 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package pkgbits
+
+import (
+	"encoding/binary"
+	"fmt"
+	"go/constant"
+	"go/token"
+	"math/big"
+	"os"
+	"runtime"
+	"strings"
+)
+
+// A PkgDecoder provides methods for decoding a package's Unified IR
+// export data.
+type PkgDecoder struct {
+	// version is the file format version.
+	version uint32
+
+	// sync indicates whether the file uses sync markers.
+	sync bool
+
+	// pkgPath is the package path for the package to be decoded.
+	//
+	// TODO(mdempsky): Remove; unneeded since CL 391014.
+	pkgPath string
+
+	// elemData is the full data payload of the encoded package.
+	// Elements are densely and contiguously packed together.
+	//
+	// The last 8 bytes of elemData are the package fingerprint.
+	elemData string
+
+	// elemEnds stores the byte-offset end positions of element
+	// bitstreams within elemData.
+	//
+	// For example, element I's bitstream data starts at elemEnds[I-1]
+	// (or 0, if I==0) and ends at elemEnds[I].
+	//
+	// Note: elemEnds is indexed by absolute indices, not
+	// section-relative indices.
+	elemEnds []uint32
+
+	// elemEndsEnds stores the index-offset end positions of relocation
+	// sections within elemEnds.
+	//
+	// For example, section K's end positions start at elemEndsEnds[K-1]
+	// (or 0, if K==0) and end at elemEndsEnds[K].
+	elemEndsEnds [numRelocs]uint32
+}
+
+// PkgPath returns the package path for the package
+//
+// TODO(mdempsky): Remove; unneeded since CL 391014.
+func (pr *PkgDecoder) PkgPath() string { return pr.pkgPath }
+
+// SyncMarkers reports whether pr uses sync markers.
+func (pr *PkgDecoder) SyncMarkers() bool { return pr.sync }
+
+// NewPkgDecoder returns a PkgDecoder initialized to read the Unified
+// IR export data from input. pkgPath is the package path for the
+// compilation unit that produced the export data.
+//
+// TODO(mdempsky): Remove pkgPath parameter; unneeded since CL 391014.
+func NewPkgDecoder(pkgPath, input string) PkgDecoder {
+	pr := PkgDecoder{
+		pkgPath: pkgPath,
+	}
+
+	// TODO(mdempsky): Implement direct indexing of input string to
+	// avoid copying the position information.
+
+	r := strings.NewReader(input)
+
+	assert(binary.Read(r, binary.LittleEndian, &pr.version) == nil)
+
+	switch pr.version {
+	default:
+		panic(fmt.Errorf("unsupported version: %v", pr.version))
+	case 0:
+		// no flags
+	case 1:
+		var flags uint32
+		assert(binary.Read(r, binary.LittleEndian, &flags) == nil)
+		pr.sync = flags&flagSyncMarkers != 0
+	}
+
+	assert(binary.Read(r, binary.LittleEndian, pr.elemEndsEnds[:]) == nil)
+
+	pr.elemEnds = make([]uint32, pr.elemEndsEnds[len(pr.elemEndsEnds)-1])
+	assert(binary.Read(r, binary.LittleEndian, pr.elemEnds[:]) == nil)
+
+	pos, err := r.Seek(0, os.SEEK_CUR)
+	assert(err == nil)
+
+	pr.elemData = input[pos:]
+	assert(len(pr.elemData)-8 == int(pr.elemEnds[len(pr.elemEnds)-1]))
+
+	return pr
+}
+
+// NumElems returns the number of elements in section k.
+func (pr *PkgDecoder) NumElems(k RelocKind) int {
+	count := int(pr.elemEndsEnds[k])
+	if k > 0 {
+		count -= int(pr.elemEndsEnds[k-1])
+	}
+	return count
+}
+
+// TotalElems returns the total number of elements across all sections.
+func (pr *PkgDecoder) TotalElems() int {
+	return len(pr.elemEnds)
+}
+
+// Fingerprint returns the package fingerprint.
+func (pr *PkgDecoder) Fingerprint() [8]byte {
+	var fp [8]byte
+	copy(fp[:], pr.elemData[len(pr.elemData)-8:])
+	return fp
+}
+
+// AbsIdx returns the absolute index for the given (section, index)
+// pair.
+func (pr *PkgDecoder) AbsIdx(k RelocKind, idx Index) int {
+	absIdx := int(idx)
+	if k > 0 {
+		absIdx += int(pr.elemEndsEnds[k-1])
+	}
+	if absIdx >= int(pr.elemEndsEnds[k]) {
+		errorf("%v:%v is out of bounds; %v", k, idx, pr.elemEndsEnds)
+	}
+	return absIdx
+}
+
+// DataIdx returns the raw element bitstream for the given (section,
+// index) pair.
+func (pr *PkgDecoder) DataIdx(k RelocKind, idx Index) string {
+	absIdx := pr.AbsIdx(k, idx)
+
+	var start uint32
+	if absIdx > 0 {
+		start = pr.elemEnds[absIdx-1]
+	}
+	end := pr.elemEnds[absIdx]
+
+	return pr.elemData[start:end]
+}
+
+// StringIdx returns the string value for the given string index.
+func (pr *PkgDecoder) StringIdx(idx Index) string {
+	return pr.DataIdx(RelocString, idx)
+}
+
+// NewDecoder returns a Decoder for the given (section, index) pair,
+// and decodes the given SyncMarker from the element bitstream.
+func (pr *PkgDecoder) NewDecoder(k RelocKind, idx Index, marker SyncMarker) Decoder {
+	r := pr.NewDecoderRaw(k, idx)
+	r.Sync(marker)
+	return r
+}
+
+// NewDecoderRaw returns a Decoder for the given (section, index) pair.
+//
+// Most callers should use NewDecoder instead.
+func (pr *PkgDecoder) NewDecoderRaw(k RelocKind, idx Index) Decoder {
+	r := Decoder{
+		common: pr,
+		k:      k,
+		Idx:    idx,
+	}
+
+	// TODO(mdempsky) r.data.Reset(...) after #44505 is resolved.
+	r.Data = *strings.NewReader(pr.DataIdx(k, idx))
+
+	r.Sync(SyncRelocs)
+	r.Relocs = make([]RelocEnt, r.Len())
+	for i := range r.Relocs {
+		r.Sync(SyncReloc)
+		r.Relocs[i] = RelocEnt{RelocKind(r.Len()), Index(r.Len())}
+	}
+
+	return r
+}
+
+// A Decoder provides methods for decoding an individual element's
+// bitstream data.
+type Decoder struct {
+	common *PkgDecoder
+
+	Relocs []RelocEnt
+	Data   strings.Reader
+
+	k   RelocKind
+	Idx Index
+}
+
+func (r *Decoder) checkErr(err error) {
+	if err != nil {
+		errorf("unexpected decoding error: %w", err)
+	}
+}
+
+func (r *Decoder) rawUvarint() uint64 {
+	x, err := binary.ReadUvarint(&r.Data)
+	r.checkErr(err)
+	return x
+}
+
+func (r *Decoder) rawVarint() int64 {
+	ux := r.rawUvarint()
+
+	// Zig-zag decode.
+	x := int64(ux >> 1)
+	if ux&1 != 0 {
+		x = ^x
+	}
+	return x
+}
+
+func (r *Decoder) rawReloc(k RelocKind, idx int) Index {
+	e := r.Relocs[idx]
+	assert(e.Kind == k)
+	return e.Idx
+}
+
+// Sync decodes a sync marker from the element bitstream and asserts
+// that it matches the expected marker.
+//
+// If r.common.sync is false, then Sync is a no-op.
+func (r *Decoder) Sync(mWant SyncMarker) {
+	if !r.common.sync {
+		return
+	}
+
+	pos, _ := r.Data.Seek(0, os.SEEK_CUR) // TODO(mdempsky): io.SeekCurrent after #44505 is resolved
+	mHave := SyncMarker(r.rawUvarint())
+	writerPCs := make([]int, r.rawUvarint())
+	for i := range writerPCs {
+		writerPCs[i] = int(r.rawUvarint())
+	}
+
+	if mHave == mWant {
+		return
+	}
+
+	// There's some tension here between printing:
+	//
+	// (1) full file paths that tools can recognize (e.g., so emacs
+	//     hyperlinks the "file:line" text for easy navigation), or
+	//
+	// (2) short file paths that are easier for humans to read (e.g., by
+	//     omitting redundant or irrelevant details, so it's easier to
+	//     focus on the useful bits that remain).
+	//
+	// The current formatting favors the former, as it seems more
+	// helpful in practice. But perhaps the formatting could be improved
+	// to better address both concerns. For example, use relative file
+	// paths if they would be shorter, or rewrite file paths to contain
+	// "$GOROOT" (like objabi.AbsFile does) if tools can be taught how
+	// to reliably expand that again.
+
+	fmt.Printf("export data desync: package %q, section %v, index %v, offset %v\n", r.common.pkgPath, r.k, r.Idx, pos)
+
+	fmt.Printf("\nfound %v, written at:\n", mHave)
+	if len(writerPCs) == 0 {
+		fmt.Printf("\t[stack trace unavailable; recompile package %q with -d=syncframes]\n", r.common.pkgPath)
+	}
+	for _, pc := range writerPCs {
+		fmt.Printf("\t%s\n", r.common.StringIdx(r.rawReloc(RelocString, pc)))
+	}
+
+	fmt.Printf("\nexpected %v, reading at:\n", mWant)
+	var readerPCs [32]uintptr // TODO(mdempsky): Dynamically size?
+	n := runtime.Callers(2, readerPCs[:])
+	for _, pc := range fmtFrames(readerPCs[:n]...) {
+		fmt.Printf("\t%s\n", pc)
+	}
+
+	// We already printed a stack trace for the reader, so now we can
+	// simply exit. Printing a second one with panic or base.Fatalf
+	// would just be noise.
+	os.Exit(1)
+}
+
+// Bool decodes and returns a bool value from the element bitstream.
+func (r *Decoder) Bool() bool {
+	r.Sync(SyncBool)
+	x, err := r.Data.ReadByte()
+	r.checkErr(err)
+	assert(x < 2)
+	return x != 0
+}
+
+// Int64 decodes and returns an int64 value from the element bitstream.
+func (r *Decoder) Int64() int64 {
+	r.Sync(SyncInt64)
+	return r.rawVarint()
+}
+
+// Int64 decodes and returns a uint64 value from the element bitstream.
+func (r *Decoder) Uint64() uint64 {
+	r.Sync(SyncUint64)
+	return r.rawUvarint()
+}
+
+// Len decodes and returns a non-negative int value from the element bitstream.
+func (r *Decoder) Len() int { x := r.Uint64(); v := int(x); assert(uint64(v) == x); return v }
+
+// Int decodes and returns an int value from the element bitstream.
+func (r *Decoder) Int() int { x := r.Int64(); v := int(x); assert(int64(v) == x); return v }
+
+// Uint decodes and returns a uint value from the element bitstream.
+func (r *Decoder) Uint() uint { x := r.Uint64(); v := uint(x); assert(uint64(v) == x); return v }
+
+// Code decodes a Code value from the element bitstream and returns
+// its ordinal value. It's the caller's responsibility to convert the
+// result to an appropriate Code type.
+//
+// TODO(mdempsky): Ideally this method would have signature "Code[T
+// Code] T" instead, but we don't allow generic methods and the
+// compiler can't depend on generics yet anyway.
+func (r *Decoder) Code(mark SyncMarker) int {
+	r.Sync(mark)
+	return r.Len()
+}
+
+// Reloc decodes a relocation of expected section k from the element
+// bitstream and returns an index to the referenced element.
+func (r *Decoder) Reloc(k RelocKind) Index {
+	r.Sync(SyncUseReloc)
+	return r.rawReloc(k, r.Len())
+}
+
+// String decodes and returns a string value from the element
+// bitstream.
+func (r *Decoder) String() string {
+	r.Sync(SyncString)
+	return r.common.StringIdx(r.Reloc(RelocString))
+}
+
+// Strings decodes and returns a variable-length slice of strings from
+// the element bitstream.
+func (r *Decoder) Strings() []string {
+	res := make([]string, r.Len())
+	for i := range res {
+		res[i] = r.String()
+	}
+	return res
+}
+
+// Value decodes and returns a constant.Value from the element
+// bitstream.
+func (r *Decoder) Value() constant.Value {
+	r.Sync(SyncValue)
+	isComplex := r.Bool()
+	val := r.scalar()
+	if isComplex {
+		val = constant.BinaryOp(val, token.ADD, constant.MakeImag(r.scalar()))
+	}
+	return val
+}
+
+func (r *Decoder) scalar() constant.Value {
+	switch tag := CodeVal(r.Code(SyncVal)); tag {
+	default:
+		panic(fmt.Errorf("unexpected scalar tag: %v", tag))
+
+	case ValBool:
+		return constant.MakeBool(r.Bool())
+	case ValString:
+		return constant.MakeString(r.String())
+	case ValInt64:
+		return constant.MakeInt64(r.Int64())
+	case ValBigInt:
+		return constant.Make(r.bigInt())
+	case ValBigRat:
+		num := r.bigInt()
+		denom := r.bigInt()
+		return constant.Make(new(big.Rat).SetFrac(num, denom))
+	case ValBigFloat:
+		return constant.Make(r.bigFloat())
+	}
+}
+
+func (r *Decoder) bigInt() *big.Int {
+	v := new(big.Int).SetBytes([]byte(r.String()))
+	if r.Bool() {
+		v.Neg(v)
+	}
+	return v
+}
+
+func (r *Decoder) bigFloat() *big.Float {
+	v := new(big.Float).SetPrec(512)
+	assert(v.UnmarshalText([]byte(r.String())) == nil)
+	return v
+}
+
+// @@@ Helpers
+
+// TODO(mdempsky): These should probably be removed. I think they're a
+// smell that the export data format is not yet quite right.
+
+// PeekPkgPath returns the package path for the specified package
+// index.
+func (pr *PkgDecoder) PeekPkgPath(idx Index) string {
+	r := pr.NewDecoder(RelocPkg, idx, SyncPkgDef)
+	path := r.String()
+	if path == "" {
+		path = pr.pkgPath
+	}
+	return path
+}
+
+// PeekObj returns the package path, object name, and CodeObj for the
+// specified object index.
+func (pr *PkgDecoder) PeekObj(idx Index) (string, string, CodeObj) {
+	r := pr.NewDecoder(RelocName, idx, SyncObject1)
+	r.Sync(SyncSym)
+	r.Sync(SyncPkg)
+	path := pr.PeekPkgPath(r.Reloc(RelocPkg))
+	name := r.String()
+	assert(name != "")
+
+	tag := CodeObj(r.Code(SyncCodeObj))
+
+	return path, name, tag
+}

vendor/golang.org/x/tools/go/internal/pkgbits/doc.go

@@ -0,0 +1,32 @@
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package pkgbits implements low-level coding abstractions for
+// Unified IR's export data format.
+//
+// At a low-level, a package is a collection of bitstream elements.
+// Each element has a "kind" and a dense, non-negative index.
+// Elements can be randomly accessed given their kind and index.
+//
+// Individual elements are sequences of variable-length values (e.g.,
+// integers, booleans, strings, go/constant values, cross-references
+// to other elements). Package pkgbits provides APIs for encoding and
+// decoding these low-level values, but the details of mapping
+// higher-level Go constructs into elements is left to higher-level
+// abstractions.
+//
+// Elements may cross-reference each other with "relocations." For
+// example, an element representing a pointer type has a relocation
+// referring to the element type.
+//
+// Go constructs may be composed as a constellation of multiple
+// elements. For example, a declared function may have one element to
+// describe the object (e.g., its name, type, position), and a
+// separate element to describe its function body. This allows readers
+// some flexibility in efficiently seeking or re-reading data (e.g.,
+// inlining requires re-reading the function body for each inlined
+// call, without needing to re-read the object-level details).
+//
+// This is a copy of internal/pkgbits in the Go implementation.
+package pkgbits

vendor/golang.org/x/tools/go/internal/pkgbits/encoder.go

@@ -0,0 +1,379 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package pkgbits
+
+import (
+	"bytes"
+	"crypto/md5"
+	"encoding/binary"
+	"go/constant"
+	"io"
+	"math/big"
+	"runtime"
+)
+
+// currentVersion is the current version number.
+//
+//   - v0: initial prototype
+//
+//   - v1: adds the flags uint32 word
+const currentVersion uint32 = 1
+
+// A PkgEncoder provides methods for encoding a package's Unified IR
+// export data.
+type PkgEncoder struct {
+	// elems holds the bitstream for previously encoded elements.
+	elems [numRelocs][]string
+
+	// stringsIdx maps previously encoded strings to their index within
+	// the RelocString section, to allow deduplication. That is,
+	// elems[RelocString][stringsIdx[s]] == s (if present).
+	stringsIdx map[string]Index
+
+	// syncFrames is the number of frames to write at each sync
+	// marker. A negative value means sync markers are omitted.
+	syncFrames int
+}
+
+// SyncMarkers reports whether pw uses sync markers.
+func (pw *PkgEncoder) SyncMarkers() bool { return pw.syncFrames >= 0 }
+
+// NewPkgEncoder returns an initialized PkgEncoder.
+//
+// syncFrames is the number of caller frames that should be serialized
+// at Sync points. Serializing additional frames results in larger
+// export data files, but can help diagnosing desync errors in
+// higher-level Unified IR reader/writer code. If syncFrames is
+// negative, then sync markers are omitted entirely.
+func NewPkgEncoder(syncFrames int) PkgEncoder {
+	return PkgEncoder{
+		stringsIdx: make(map[string]Index),
+		syncFrames: syncFrames,
+	}
+}
+
+// DumpTo writes the package's encoded data to out0 and returns the
+// package fingerprint.
+func (pw *PkgEncoder) DumpTo(out0 io.Writer) (fingerprint [8]byte) {
+	h := md5.New()
+	out := io.MultiWriter(out0, h)
+
+	writeUint32 := func(x uint32) {
+		assert(binary.Write(out, binary.LittleEndian, x) == nil)
+	}
+
+	writeUint32(currentVersion)
+
+	var flags uint32
+	if pw.SyncMarkers() {
+		flags |= flagSyncMarkers
+	}
+	writeUint32(flags)
+
+	// Write elemEndsEnds.
+	var sum uint32
+	for _, elems := range &pw.elems {
+		sum += uint32(len(elems))
+		writeUint32(sum)
+	}
+
+	// Write elemEnds.
+	sum = 0
+	for _, elems := range &pw.elems {
+		for _, elem := range elems {
+			sum += uint32(len(elem))
+			writeUint32(sum)
+		}
+	}
+
+	// Write elemData.
+	for _, elems := range &pw.elems {
+		for _, elem := range elems {
+			_, err := io.WriteString(out, elem)
+			assert(err == nil)
+		}
+	}
+
+	// Write fingerprint.
+	copy(fingerprint[:], h.Sum(nil))
+	_, err := out0.Write(fingerprint[:])
+	assert(err == nil)
+
+	return
+}
+
+// StringIdx adds a string value to the strings section, if not
+// already present, and returns its index.
+func (pw *PkgEncoder) StringIdx(s string) Index {
+	if idx, ok := pw.stringsIdx[s]; ok {
+		assert(pw.elems[RelocString][idx] == s)
+		return idx
+	}
+
+	idx := Index(len(pw.elems[RelocString]))
+	pw.elems[RelocString] = append(pw.elems[RelocString], s)
+	pw.stringsIdx[s] = idx
+	return idx
+}
+
+// NewEncoder returns an Encoder for a new element within the given
+// section, and encodes the given SyncMarker as the start of the
+// element bitstream.
+func (pw *PkgEncoder) NewEncoder(k RelocKind, marker SyncMarker) Encoder {
+	e := pw.NewEncoderRaw(k)
+	e.Sync(marker)
+	return e
+}
+
+// NewEncoderRaw returns an Encoder for a new element within the given
+// section.
+//
+// Most callers should use NewEncoder instead.
+func (pw *PkgEncoder) NewEncoderRaw(k RelocKind) Encoder {
+	idx := Index(len(pw.elems[k]))
+	pw.elems[k] = append(pw.elems[k], "") // placeholder
+
+	return Encoder{
+		p:   pw,
+		k:   k,
+		Idx: idx,
+	}
+}
+
+// An Encoder provides methods for encoding an individual element's
+// bitstream data.
+type Encoder struct {
+	p *PkgEncoder
+
+	Relocs []RelocEnt
+	Data   bytes.Buffer // accumulated element bitstream data
+
+	encodingRelocHeader bool
+
+	k   RelocKind
+	Idx Index // index within relocation section
+}
+
+// Flush finalizes the element's bitstream and returns its Index.
+func (w *Encoder) Flush() Index {
+	var sb bytes.Buffer // TODO(mdempsky): strings.Builder after #44505 is resolved
+
+	// Backup the data so we write the relocations at the front.
+	var tmp bytes.Buffer
+	io.Copy(&tmp, &w.Data)
+
+	// TODO(mdempsky): Consider writing these out separately so they're
+	// easier to strip, along with function bodies, so that we can prune
+	// down to just the data that's relevant to go/types.
+	if w.encodingRelocHeader {
+		panic("encodingRelocHeader already true; recursive flush?")
+	}
+	w.encodingRelocHeader = true
+	w.Sync(SyncRelocs)
+	w.Len(len(w.Relocs))
+	for _, rEnt := range w.Relocs {
+		w.Sync(SyncReloc)
+		w.Len(int(rEnt.Kind))
+		w.Len(int(rEnt.Idx))
+	}
+
+	io.Copy(&sb, &w.Data)
+	io.Copy(&sb, &tmp)
+	w.p.elems[w.k][w.Idx] = sb.String()
+
+	return w.Idx
+}
+
+func (w *Encoder) checkErr(err error) {
+	if err != nil {
+		errorf("unexpected encoding error: %v", err)
+	}
+}
+
+func (w *Encoder) rawUvarint(x uint64) {
+	var buf [binary.MaxVarintLen64]byte
+	n := binary.PutUvarint(buf[:], x)
+	_, err := w.Data.Write(buf[:n])
+	w.checkErr(err)
+}
+
+func (w *Encoder) rawVarint(x int64) {
+	// Zig-zag encode.
+	ux := uint64(x) << 1
+	if x < 0 {
+		ux = ^ux
+	}
+
+	w.rawUvarint(ux)
+}
+
+func (w *Encoder) rawReloc(r RelocKind, idx Index) int {
+	// TODO(mdempsky): Use map for lookup; this takes quadratic time.
+	for i, rEnt := range w.Relocs {
+		if rEnt.Kind == r && rEnt.Idx == idx {
+			return i
+		}
+	}
+
+	i := len(w.Relocs)
+	w.Relocs = append(w.Relocs, RelocEnt{r, idx})
+	return i
+}
+
+func (w *Encoder) Sync(m SyncMarker) {
+	if !w.p.SyncMarkers() {
+		return
+	}
+
+	// Writing out stack frame string references requires working
+	// relocations, but writing out the relocations themselves involves
+	// sync markers. To prevent infinite recursion, we simply trim the
+	// stack frame for sync markers within the relocation header.
+	var frames []string
+	if !w.encodingRelocHeader && w.p.syncFrames > 0 {
+		pcs := make([]uintptr, w.p.syncFrames)
+		n := runtime.Callers(2, pcs)
+		frames = fmtFrames(pcs[:n]...)
+	}
+
+	// TODO(mdempsky): Save space by writing out stack frames as a
+	// linked list so we can share common stack frames.
+	w.rawUvarint(uint64(m))
+	w.rawUvarint(uint64(len(frames)))
+	for _, frame := range frames {
+		w.rawUvarint(uint64(w.rawReloc(RelocString, w.p.StringIdx(frame))))
+	}
+}
+
+// Bool encodes and writes a bool value into the element bitstream,
+// and then returns the bool value.
+//
+// For simple, 2-alternative encodings, the idiomatic way to call Bool
+// is something like:
+//
+//	if w.Bool(x != 0) {
+//		// alternative #1
+//	} else {
+//		// alternative #2
+//	}
+//
+// For multi-alternative encodings, use Code instead.
+func (w *Encoder) Bool(b bool) bool {
+	w.Sync(SyncBool)
+	var x byte
+	if b {
+		x = 1
+	}
+	err := w.Data.WriteByte(x)
+	w.checkErr(err)
+	return b
+}
+
+// Int64 encodes and writes an int64 value into the element bitstream.
+func (w *Encoder) Int64(x int64) {
+	w.Sync(SyncInt64)
+	w.rawVarint(x)
+}
+
+// Uint64 encodes and writes a uint64 value into the element bitstream.
+func (w *Encoder) Uint64(x uint64) {
+	w.Sync(SyncUint64)
+	w.rawUvarint(x)
+}
+
+// Len encodes and writes a non-negative int value into the element bitstream.
+func (w *Encoder) Len(x int) { assert(x >= 0); w.Uint64(uint64(x)) }
+
+// Int encodes and writes an int value into the element bitstream.
+func (w *Encoder) Int(x int) { w.Int64(int64(x)) }
+
+// Len encodes and writes a uint value into the element bitstream.
+func (w *Encoder) Uint(x uint) { w.Uint64(uint64(x)) }
+
+// Reloc encodes and writes a relocation for the given (section,
+// index) pair into the element bitstream.
+//
+// Note: Only the index is formally written into the element
+// bitstream, so bitstream decoders must know from context which
+// section an encoded relocation refers to.
+func (w *Encoder) Reloc(r RelocKind, idx Index) {
+	w.Sync(SyncUseReloc)
+	w.Len(w.rawReloc(r, idx))
+}
+
+// Code encodes and writes a Code value into the element bitstream.
+func (w *Encoder) Code(c Code) {
+	w.Sync(c.Marker())
+	w.Len(c.Value())
+}
+
+// String encodes and writes a string value into the element
+// bitstream.
+//
+// Internally, strings are deduplicated by adding them to the strings
+// section (if not already present), and then writing a relocation
+// into the element bitstream.
+func (w *Encoder) String(s string) {
+	w.Sync(SyncString)
+	w.Reloc(RelocString, w.p.StringIdx(s))
+}
+
+// Strings encodes and writes a variable-length slice of strings into
+// the element bitstream.
+func (w *Encoder) Strings(ss []string) {
+	w.Len(len(ss))
+	for _, s := range ss {
+		w.String(s)
+	}
+}
+
+// Value encodes and writes a constant.Value into the element
+// bitstream.
+func (w *Encoder) Value(val constant.Value) {
+	w.Sync(SyncValue)
+	if w.Bool(val.Kind() == constant.Complex) {
+		w.scalar(constant.Real(val))
+		w.scalar(constant.Imag(val))
+	} else {
+		w.scalar(val)
+	}
+}
+
+func (w *Encoder) scalar(val constant.Value) {
+	switch v := constant.Val(val).(type) {
+	default:
+		errorf("unhandled %v (%v)", val, val.Kind())
+	case bool:
+		w.Code(ValBool)
+		w.Bool(v)
+	case string:
+		w.Code(ValString)
+		w.String(v)
+	case int64:
+		w.Code(ValInt64)
+		w.Int64(v)
+	case *big.Int:
+		w.Code(ValBigInt)
+		w.bigInt(v)
+	case *big.Rat:
+		w.Code(ValBigRat)
+		w.bigInt(v.Num())
+		w.bigInt(v.Denom())
+	case *big.Float:
+		w.Code(ValBigFloat)
+		w.bigFloat(v)
+	}
+}
+
+func (w *Encoder) bigInt(v *big.Int) {
+	b := v.Bytes()
+	w.String(string(b)) // TODO: More efficient encoding.
+	w.Bool(v.Sign() < 0)
+}
+
+func (w *Encoder) bigFloat(v *big.Float) {
+	b := v.Append(nil, 'p', -1)
+	w.String(string(b)) // TODO: More efficient encoding.
+}

vendor/golang.org/x/tools/go/internal/pkgbits/flags.go

@@ -0,0 +1,9 @@
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package pkgbits
+
+const (
+	flagSyncMarkers = 1 << iota // file format contains sync markers
+)

vendor/golang.org/x/tools/go/internal/pkgbits/frames_go1.go

@@ -0,0 +1,21 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build !go1.7
+// +build !go1.7
+
+// TODO(mdempsky): Remove after #44505 is resolved
+
+package pkgbits
+
+import "runtime"
+
+func walkFrames(pcs []uintptr, visit frameVisitor) {
+	for _, pc := range pcs {
+		fn := runtime.FuncForPC(pc)
+		file, line := fn.FileLine(pc)
+
+		visit(file, line, fn.Name(), pc-fn.Entry())
+	}
+}

vendor/golang.org/x/tools/go/internal/pkgbits/frames_go17.go

@@ -0,0 +1,28 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build go1.7
+// +build go1.7
+
+package pkgbits
+
+import "runtime"
+
+// walkFrames calls visit for each call frame represented by pcs.
+//
+// pcs should be a slice of PCs, as returned by runtime.Callers.
+func walkFrames(pcs []uintptr, visit frameVisitor) {
+	if len(pcs) == 0 {
+		return
+	}
+
+	frames := runtime.CallersFrames(pcs)
+	for {
+		frame, more := frames.Next()
+		visit(frame.File, frame.Line, frame.Function, frame.PC-frame.Entry)
+		if !more {
+			return
+		}
+	}
+}

vendor/golang.org/x/tools/go/internal/pkgbits/reloc.go

@@ -0,0 +1,42 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package pkgbits
+
+// A RelocKind indicates a particular section within a unified IR export.
+type RelocKind int
+
+// An Index represents a bitstream element index within a particular
+// section.
+type Index int
+
+// A relocEnt (relocation entry) is an entry in an element's local
+// reference table.
+//
+// TODO(mdempsky): Rename this too.
+type RelocEnt struct {
+	Kind RelocKind
+	Idx  Index
+}
+
+// Reserved indices within the meta relocation section.
+const (
+	PublicRootIdx  Index = 0
+	PrivateRootIdx Index = 1
+)
+
+const (
+	RelocString RelocKind = iota
+	RelocMeta
+	RelocPosBase
+	RelocPkg
+	RelocName
+	RelocType
+	RelocObj
+	RelocObjExt
+	RelocObjDict
+	RelocBody
+
+	numRelocs = iota
+)

vendor/golang.org/x/tools/go/internal/pkgbits/support.go

@@ -0,0 +1,17 @@
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package pkgbits
+
+import "fmt"
+
+func assert(b bool) {
+	if !b {
+		panic("assertion failed")
+	}
+}
+
+func errorf(format string, args ...interface{}) {
+	panic(fmt.Errorf(format, args...))
+}

vendor/golang.org/x/tools/go/internal/pkgbits/sync.go

@@ -0,0 +1,113 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package pkgbits
+
+import (
+	"fmt"
+	"strings"
+)
+
+// fmtFrames formats a backtrace for reporting reader/writer desyncs.
+func fmtFrames(pcs ...uintptr) []string {
+	res := make([]string, 0, len(pcs))
+	walkFrames(pcs, func(file string, line int, name string, offset uintptr) {
+		// Trim package from function name. It's just redundant noise.
+		name = strings.TrimPrefix(name, "cmd/compile/internal/noder.")
+
+		res = append(res, fmt.Sprintf("%s:%v: %s +0x%v", file, line, name, offset))
+	})
+	return res
+}
+
+type frameVisitor func(file string, line int, name string, offset uintptr)
+
+// SyncMarker is an enum type that represents markers that may be
+// written to export data to ensure the reader and writer stay
+// synchronized.
+type SyncMarker int
+
+//go:generate stringer -type=SyncMarker -trimprefix=Sync
+
+const (
+	_ SyncMarker = iota
+
+	// Public markers (known to go/types importers).
+
+	// Low-level coding markers.
+	SyncEOF
+	SyncBool
+	SyncInt64
+	SyncUint64
+	SyncString
+	SyncValue
+	SyncVal
+	SyncRelocs
+	SyncReloc
+	SyncUseReloc
+
+	// Higher-level object and type markers.
+	SyncPublic
+	SyncPos
+	SyncPosBase
+	SyncObject
+	SyncObject1
+	SyncPkg
+	SyncPkgDef
+	SyncMethod
+	SyncType
+	SyncTypeIdx
+	SyncTypeParamNames
+	SyncSignature
+	SyncParams
+	SyncParam
+	SyncCodeObj
+	SyncSym
+	SyncLocalIdent
+	SyncSelector
+
+	// Private markers (only known to cmd/compile).
+	SyncPrivate
+
+	SyncFuncExt
+	SyncVarExt
+	SyncTypeExt
+	SyncPragma
+
+	SyncExprList
+	SyncExprs
+	SyncExpr
+	SyncExprType
+	SyncAssign
+	SyncOp
+	SyncFuncLit
+	SyncCompLit
+
+	SyncDecl
+	SyncFuncBody
+	SyncOpenScope
+	SyncCloseScope
+	SyncCloseAnotherScope
+	SyncDeclNames
+	SyncDeclName
+
+	SyncStmts
+	SyncBlockStmt
+	SyncIfStmt
+	SyncForStmt
+	SyncSwitchStmt
+	SyncRangeStmt
+	SyncCaseClause
+	SyncCommClause
+	SyncSelectStmt
+	SyncDecls
+	SyncLabeledStmt
+	SyncUseObjLocal
+	SyncAddLocal
+	SyncLinkname
+	SyncStmt1
+	SyncStmtsEnd
+	SyncLabel
+	SyncOptLabel
+)

vendor/golang.org/x/tools/go/internal/pkgbits/syncmarker_string.go

@@ -0,0 +1,89 @@
+// Code generated by "stringer -type=SyncMarker -trimprefix=Sync"; DO NOT EDIT.
+
+package pkgbits
+
+import "strconv"
+
+func _() {
+	// An "invalid array index" compiler error signifies that the constant values have changed.
+	// Re-run the stringer command to generate them again.
+	var x [1]struct{}
+	_ = x[SyncEOF-1]
+	_ = x[SyncBool-2]
+	_ = x[SyncInt64-3]
+	_ = x[SyncUint64-4]
+	_ = x[SyncString-5]
+	_ = x[SyncValue-6]
+	_ = x[SyncVal-7]
+	_ = x[SyncRelocs-8]
+	_ = x[SyncReloc-9]
+	_ = x[SyncUseReloc-10]
+	_ = x[SyncPublic-11]
+	_ = x[SyncPos-12]
+	_ = x[SyncPosBase-13]
+	_ = x[SyncObject-14]
+	_ = x[SyncObject1-15]
+	_ = x[SyncPkg-16]
+	_ = x[SyncPkgDef-17]
+	_ = x[SyncMethod-18]
+	_ = x[SyncType-19]
+	_ = x[SyncTypeIdx-20]
+	_ = x[SyncTypeParamNames-21]
+	_ = x[SyncSignature-22]
+	_ = x[SyncParams-23]
+	_ = x[SyncParam-24]
+	_ = x[SyncCodeObj-25]
+	_ = x[SyncSym-26]
+	_ = x[SyncLocalIdent-27]
+	_ = x[SyncSelector-28]
+	_ = x[SyncPrivate-29]
+	_ = x[SyncFuncExt-30]
+	_ = x[SyncVarExt-31]
+	_ = x[SyncTypeExt-32]
+	_ = x[SyncPragma-33]
+	_ = x[SyncExprList-34]
+	_ = x[SyncExprs-35]
+	_ = x[SyncExpr-36]
+	_ = x[SyncExprType-37]
+	_ = x[SyncAssign-38]
+	_ = x[SyncOp-39]
+	_ = x[SyncFuncLit-40]
+	_ = x[SyncCompLit-41]
+	_ = x[SyncDecl-42]
+	_ = x[SyncFuncBody-43]
+	_ = x[SyncOpenScope-44]
+	_ = x[SyncCloseScope-45]
+	_ = x[SyncCloseAnotherScope-46]
+	_ = x[SyncDeclNames-47]
+	_ = x[SyncDeclName-48]
+	_ = x[SyncStmts-49]
+	_ = x[SyncBlockStmt-50]
+	_ = x[SyncIfStmt-51]
+	_ = x[SyncForStmt-52]
+	_ = x[SyncSwitchStmt-53]
+	_ = x[SyncRangeStmt-54]
+	_ = x[SyncCaseClause-55]
+	_ = x[SyncCommClause-56]
+	_ = x[SyncSelectStmt-57]
+	_ = x[SyncDecls-58]
+	_ = x[SyncLabeledStmt-59]
+	_ = x[SyncUseObjLocal-60]
+	_ = x[SyncAddLocal-61]
+	_ = x[SyncLinkname-62]
+	_ = x[SyncStmt1-63]
+	_ = x[SyncStmtsEnd-64]
+	_ = x[SyncLabel-65]
+	_ = x[SyncOptLabel-66]
+}
+
+const _SyncMarker_name = "EOFBoolInt64Uint64StringValueValRelocsRelocUseRelocPublicPosPosBaseObjectObject1PkgPkgDefMethodTypeTypeIdxTypeParamNamesSignatureParamsParamCodeObjSymLocalIdentSelectorPrivateFuncExtVarExtTypeExtPragmaExprListExprsExprExprTypeAssignOpFuncLitCompLitDeclFuncBodyOpenScopeCloseScopeCloseAnotherScopeDeclNamesDeclNameStmtsBlockStmtIfStmtForStmtSwitchStmtRangeStmtCaseClauseCommClauseSelectStmtDeclsLabeledStmtUseObjLocalAddLocalLinknameStmt1StmtsEndLabelOptLabel"
+
+var _SyncMarker_index = [...]uint16{0, 3, 7, 12, 18, 24, 29, 32, 38, 43, 51, 57, 60, 67, 73, 80, 83, 89, 95, 99, 106, 120, 129, 135, 140, 147, 150, 160, 168, 175, 182, 188, 195, 201, 209, 214, 218, 226, 232, 234, 241, 248, 252, 260, 269, 279, 296, 305, 313, 318, 327, 333, 340, 350, 359, 369, 379, 389, 394, 405, 416, 424, 432, 437, 445, 450, 458}
+
+func (i SyncMarker) String() string {
+	i -= 1
+	if i < 0 || i >= SyncMarker(len(_SyncMarker_index)-1) {
+		return "SyncMarker(" + strconv.FormatInt(int64(i+1), 10) + ")"
+	}
+	return _SyncMarker_name[_SyncMarker_index[i]:_SyncMarker_index[i+1]]
+}

vendor/golang.org/x/tools/go/packages/doc.go

@@ -67,7 +67,6 @@ Most tools should pass their command-line arguments (after any flags)
 uninterpreted to the loader, so that the loader can interpret them
 according to the conventions of the underlying build system.
 See the Example function for typical usage.
-
 */
 package packages // import "golang.org/x/tools/go/packages"
 

vendor/golang.org/x/tools/go/packages/golist.go

@@ -26,7 +26,6 @@ import (
 	"golang.org/x/tools/go/internal/packagesdriver"
 	"golang.org/x/tools/internal/gocommand"
 	"golang.org/x/tools/internal/packagesinternal"
-	"golang.org/x/xerrors"
 )
 
 // debug controls verbose logging.
@@ -303,11 +302,12 @@ func (state *golistState) runContainsQueries(response *responseDeduper, queries
 		}
 		dirResponse, err := state.createDriverResponse(pattern)
 
-		// If there was an error loading the package, or the package is returned
-		// with errors, try to load the file as an ad-hoc package.
+		// If there was an error loading the package, or no packages are returned,
+		// or the package is returned with errors, try to load the file as an
+		// ad-hoc package.
 		// Usually the error will appear in a returned package, but may not if we're
 		// in module mode and the ad-hoc is located outside a module.
-		if err != nil || len(dirResponse.Packages) == 1 && len(dirResponse.Packages[0].GoFiles) == 0 &&
+		if err != nil || len(dirResponse.Packages) == 0 || len(dirResponse.Packages) == 1 && len(dirResponse.Packages[0].GoFiles) == 0 &&
 			len(dirResponse.Packages[0].Errors) == 1 {
 			var queryErr error
 			if dirResponse, queryErr = state.adhocPackage(pattern, query); queryErr != nil {
@@ -393,6 +393,8 @@ type jsonPackage struct {
 	CompiledGoFiles   []string
 	IgnoredGoFiles    []string
 	IgnoredOtherFiles []string
+	EmbedPatterns     []string
+	EmbedFiles        []string
 	CFiles            []string
 	CgoFiles          []string
 	CXXFiles          []string
@@ -444,7 +446,11 @@ func (state *golistState) createDriverResponse(words ...string) (*driverResponse
 
 	// Run "go list" for complete
 	// information on the specified packages.
-	buf, err := state.invokeGo("list", golistargs(state.cfg, words)...)
+	goVersion, err := state.getGoVersion()
+	if err != nil {
+		return nil, err
+	}
+	buf, err := state.invokeGo("list", golistargs(state.cfg, words, goVersion)...)
 	if err != nil {
 		return nil, err
 	}
@@ -565,6 +571,8 @@ func (state *golistState) createDriverResponse(words ...string) (*driverResponse
 			GoFiles:         absJoin(p.Dir, p.GoFiles, p.CgoFiles),
 			CompiledGoFiles: absJoin(p.Dir, p.CompiledGoFiles),
 			OtherFiles:      absJoin(p.Dir, otherFiles(p)...),
+			EmbedFiles:      absJoin(p.Dir, p.EmbedFiles),
+			EmbedPatterns:   absJoin(p.Dir, p.EmbedPatterns),
 			IgnoredFiles:    absJoin(p.Dir, p.IgnoredGoFiles, p.IgnoredOtherFiles),
 			forTest:         p.ForTest,
 			depsErrors:      p.DepsErrors,
@@ -805,17 +813,83 @@ func absJoin(dir string, fileses ...[]string) (res []string) {
 	return res
 }
 
-func golistargs(cfg *Config, words []string) []string {
+func jsonFlag(cfg *Config, goVersion int) string {
+	if goVersion < 19 {
+		return "-json"
+	}
+	var fields []string
+	added := make(map[string]bool)
+	addFields := func(fs ...string) {
+		for _, f := range fs {
+			if !added[f] {
+				added[f] = true
+				fields = append(fields, f)
+			}
+		}
+	}
+	addFields("Name", "ImportPath", "Error") // These fields are always needed
+	if cfg.Mode&NeedFiles != 0 || cfg.Mode&NeedTypes != 0 {
+		addFields("Dir", "GoFiles", "IgnoredGoFiles", "IgnoredOtherFiles", "CFiles",
+			"CgoFiles", "CXXFiles", "MFiles", "HFiles", "FFiles", "SFiles",
+			"SwigFiles", "SwigCXXFiles", "SysoFiles")
+		if cfg.Tests {
+			addFields("TestGoFiles", "XTestGoFiles")
+		}
+	}
+	if cfg.Mode&NeedTypes != 0 {
+		// CompiledGoFiles seems to be required for the test case TestCgoNoSyntax,
+		// even when -compiled isn't passed in.
+		// TODO(#52435): Should we make the test ask for -compiled, or automatically
+		// request CompiledGoFiles in certain circumstances?
+		addFields("Dir", "CompiledGoFiles")
+	}
+	if cfg.Mode&NeedCompiledGoFiles != 0 {
+		addFields("Dir", "CompiledGoFiles", "Export")
+	}
+	if cfg.Mode&NeedImports != 0 {
+		// When imports are requested, DepOnly is used to distinguish between packages
+		// explicitly requested and transitive imports of those packages.
+		addFields("DepOnly", "Imports", "ImportMap")
+		if cfg.Tests {
+			addFields("TestImports", "XTestImports")
+		}
+	}
+	if cfg.Mode&NeedDeps != 0 {
+		addFields("DepOnly")
+	}
+	if usesExportData(cfg) {
+		// Request Dir in the unlikely case Export is not absolute.
+		addFields("Dir", "Export")
+	}
+	if cfg.Mode&needInternalForTest != 0 {
+		addFields("ForTest")
+	}
+	if cfg.Mode&needInternalDepsErrors != 0 {
+		addFields("DepsErrors")
+	}
+	if cfg.Mode&NeedModule != 0 {
+		addFields("Module")
+	}
+	if cfg.Mode&NeedEmbedFiles != 0 {
+		addFields("EmbedFiles")
+	}
+	if cfg.Mode&NeedEmbedPatterns != 0 {
+		addFields("EmbedPatterns")
+	}
+	return "-json=" + strings.Join(fields, ",")
+}
+
+func golistargs(cfg *Config, words []string, goVersion int) []string {
 	const findFlags = NeedImports | NeedTypes | NeedSyntax | NeedTypesInfo
 	fullargs := []string{
-		"-e", "-json",
+		"-e", jsonFlag(cfg, goVersion),
 		fmt.Sprintf("-compiled=%t", cfg.Mode&(NeedCompiledGoFiles|NeedSyntax|NeedTypes|NeedTypesInfo|NeedTypesSizes) != 0),
 		fmt.Sprintf("-test=%t", cfg.Tests),
 		fmt.Sprintf("-export=%t", usesExportData(cfg)),
 		fmt.Sprintf("-deps=%t", cfg.Mode&NeedImports != 0),
 		// go list doesn't let you pass -test and -find together,
 		// probably because you'd just get the TestMain.
-		fmt.Sprintf("-find=%t", !cfg.Tests && cfg.Mode&findFlags == 0),
+		fmt.Sprintf("-find=%t", !cfg.Tests && cfg.Mode&findFlags == 0 && !usesExportData(cfg)),
 	}
 	fullargs = append(fullargs, cfg.BuildFlags...)
 	fullargs = append(fullargs, "--")
@@ -879,7 +953,7 @@ func (state *golistState) invokeGo(verb string, args ...string) (*bytes.Buffer,
 		if !ok {
 			// Catastrophic error:
 			// - context cancellation
-			return nil, xerrors.Errorf("couldn't run 'go': %w", err)
+			return nil, fmt.Errorf("couldn't run 'go': %w", err)
 		}
 
 		// Old go version?

vendor/golang.org/x/tools/go/packages/loadmode_string.go

@@ -15,7 +15,7 @@ var allModes = []LoadMode{
 	NeedCompiledGoFiles,
 	NeedImports,
 	NeedDeps,
-	NeedExportsFile,
+	NeedExportFile,
 	NeedTypes,
 	NeedSyntax,
 	NeedTypesInfo,
@@ -28,7 +28,7 @@ var modeStrings = []string{
 	"NeedCompiledGoFiles",
 	"NeedImports",
 	"NeedDeps",
-	"NeedExportsFile",
+	"NeedExportFile",
 	"NeedTypes",
 	"NeedSyntax",
 	"NeedTypesInfo",

vendor/golang.org/x/tools/go/packages/packages.go

@@ -39,9 +39,6 @@ import (
 // Load may return more information than requested.
 type LoadMode int
 
-// TODO(matloob): When a V2 of go/packages is released, rename NeedExportsFile to
-// NeedExportFile to make it consistent with the Package field it's adding.
-
 const (
 	// NeedName adds Name and PkgPath.
 	NeedName LoadMode = 1 << iota
@@ -59,8 +56,8 @@ const (
 	// NeedDeps adds the fields requested by the LoadMode in the packages in Imports.
 	NeedDeps
 
-	// NeedExportsFile adds ExportFile.
-	NeedExportsFile
+	// NeedExportFile adds ExportFile.
+	NeedExportFile
 
 	// NeedTypes adds Types, Fset, and IllTyped.
 	NeedTypes
@@ -74,12 +71,25 @@ const (
 	// NeedTypesSizes adds TypesSizes.
 	NeedTypesSizes
 
+	// needInternalDepsErrors adds the internal deps errors field for use by gopls.
+	needInternalDepsErrors
+
+	// needInternalForTest adds the internal forTest field.
+	// Tests must also be set on the context for this field to be populated.
+	needInternalForTest
+
 	// typecheckCgo enables full support for type checking cgo. Requires Go 1.15+.
 	// Modifies CompiledGoFiles and Types, and has no effect on its own.
 	typecheckCgo
 
 	// NeedModule adds Module.
 	NeedModule
+
+	// NeedEmbedFiles adds EmbedFiles.
+	NeedEmbedFiles
+
+	// NeedEmbedPatterns adds EmbedPatterns.
+	NeedEmbedPatterns
 )
 
 const (
@@ -102,6 +112,9 @@ const (
 	// Deprecated: LoadAllSyntax exists for historical compatibility
 	// and should not be used. Please directly specify the needed fields using the Need values.
 	LoadAllSyntax = LoadSyntax | NeedDeps
+
+	// Deprecated: NeedExportsFile is a historical misspelling of NeedExportFile.
+	NeedExportsFile = NeedExportFile
 )
 
 // A Config specifies details about how packages should be loaded.
@@ -296,6 +309,14 @@ type Package struct {
 	// including assembly, C, C++, Fortran, Objective-C, SWIG, and so on.
 	OtherFiles []string
 
+	// EmbedFiles lists the absolute file paths of the package's files
+	// embedded with go:embed.
+	EmbedFiles []string
+
+	// EmbedPatterns lists the absolute file patterns of the package's
+	// files embedded with go:embed.
+	EmbedPatterns []string
+
 	// IgnoredFiles lists source files that are not part of the package
 	// using the current build configuration but that might be part of
 	// the package using other build configurations.
@@ -389,6 +410,8 @@ func init() {
 		config.(*Config).modFlag = value
 	}
 	packagesinternal.TypecheckCgo = int(typecheckCgo)
+	packagesinternal.DepsErrors = int(needInternalDepsErrors)
+	packagesinternal.ForTest = int(needInternalForTest)
 }
 
 // An Error describes a problem with a package's metadata, syntax, or types.
@@ -431,6 +454,8 @@ type flatPackage struct {
 	GoFiles         []string          `json:",omitempty"`
 	CompiledGoFiles []string          `json:",omitempty"`
 	OtherFiles      []string          `json:",omitempty"`
+	EmbedFiles      []string          `json:",omitempty"`
+	EmbedPatterns   []string          `json:",omitempty"`
 	IgnoredFiles    []string          `json:",omitempty"`
 	ExportFile      string            `json:",omitempty"`
 	Imports         map[string]string `json:",omitempty"`
@@ -454,6 +479,8 @@ func (p *Package) MarshalJSON() ([]byte, error) {
 		GoFiles:         p.GoFiles,
 		CompiledGoFiles: p.CompiledGoFiles,
 		OtherFiles:      p.OtherFiles,
+		EmbedFiles:      p.EmbedFiles,
+		EmbedPatterns:   p.EmbedPatterns,
 		IgnoredFiles:    p.IgnoredFiles,
 		ExportFile:      p.ExportFile,
 	}
@@ -481,6 +508,8 @@ func (p *Package) UnmarshalJSON(b []byte) error {
 		GoFiles:         flat.GoFiles,
 		CompiledGoFiles: flat.CompiledGoFiles,
 		OtherFiles:      flat.OtherFiles,
+		EmbedFiles:      flat.EmbedFiles,
+		EmbedPatterns:   flat.EmbedPatterns,
 		ExportFile:      flat.ExportFile,
 	}
 	if len(flat.Imports) > 0 {
@@ -614,7 +643,7 @@ func (ld *loader) refine(roots []string, list ...*Package) ([]*Package, error) {
 		needsrc := ((ld.Mode&(NeedSyntax|NeedTypesInfo) != 0 && (rootIndex >= 0 || ld.Mode&NeedDeps != 0)) ||
 			// ... or if we need types and the exportData is invalid. We fall back to (incompletely)
 			// typechecking packages from source if they fail to compile.
-			(ld.Mode&NeedTypes|NeedTypesInfo != 0 && exportDataInvalid)) && pkg.PkgPath != "unsafe"
+			(ld.Mode&(NeedTypes|NeedTypesInfo) != 0 && exportDataInvalid)) && pkg.PkgPath != "unsafe"
 		lpkg := &loaderPackage{
 			Package:   pkg,
 			needtypes: needtypes,
@@ -752,13 +781,19 @@ func (ld *loader) refine(roots []string, list ...*Package) ([]*Package, error) {
 			ld.pkgs[i].OtherFiles = nil
 			ld.pkgs[i].IgnoredFiles = nil
 		}
+		if ld.requestedMode&NeedEmbedFiles == 0 {
+			ld.pkgs[i].EmbedFiles = nil
+		}
+		if ld.requestedMode&NeedEmbedPatterns == 0 {
+			ld.pkgs[i].EmbedPatterns = nil
+		}
 		if ld.requestedMode&NeedCompiledGoFiles == 0 {
 			ld.pkgs[i].CompiledGoFiles = nil
 		}
 		if ld.requestedMode&NeedImports == 0 {
 			ld.pkgs[i].Imports = nil
 		}
-		if ld.requestedMode&NeedExportsFile == 0 {
+		if ld.requestedMode&NeedExportFile == 0 {
 			ld.pkgs[i].ExportFile = ""
 		}
 		if ld.requestedMode&NeedTypes == 0 {
@@ -1053,7 +1088,6 @@ func (ld *loader) parseFile(filename string) (*ast.File, error) {
 //
 // Because files are scanned in parallel, the token.Pos
 // positions of the resulting ast.Files are not ordered.
-//
 func (ld *loader) parseFiles(filenames []string) ([]*ast.File, []error) {
 	var wg sync.WaitGroup
 	n := len(filenames)
@@ -1097,7 +1131,6 @@ func (ld *loader) parseFiles(filenames []string) ([]*ast.File, []error) {
 
 // sameFile returns true if x and y have the same basename and denote
 // the same file.
-//
 func sameFile(x, y string) bool {
 	if x == y {
 		// It could be the case that y doesn't exist.
@@ -1210,8 +1243,13 @@ func (ld *loader) loadFromExportData(lpkg *loaderPackage) (*types.Package, error
 	if err != nil {
 		return nil, fmt.Errorf("reading %s: %v", lpkg.ExportFile, err)
 	}
+	if _, ok := view["go.shape"]; ok {
+		// Account for the pseudopackage "go.shape" that gets
+		// created by generic code.
+		viewLen++
+	}
 	if viewLen != len(view) {
-		log.Fatalf("Unexpected package creation during export data loading")
+		log.Panicf("golang.org/x/tools/go/packages: unexpected new packages during load of %s", lpkg.PkgPath)
 	}
 
 	lpkg.Types = tpkg
@@ -1222,17 +1260,8 @@ func (ld *loader) loadFromExportData(lpkg *loaderPackage) (*types.Package, error
 
 // impliedLoadMode returns loadMode with its dependencies.
 func impliedLoadMode(loadMode LoadMode) LoadMode {
-	if loadMode&NeedTypesInfo != 0 && loadMode&NeedImports == 0 {
-		// If NeedTypesInfo, go/packages needs to do typechecking itself so it can
-		// associate type info with the AST. To do so, we need the export data
-		// for dependencies, which means we need to ask for the direct dependencies.
-		// NeedImports is used to ask for the direct dependencies.
-		loadMode |= NeedImports
-	}
-
-	if loadMode&NeedDeps != 0 && loadMode&NeedImports == 0 {
-		// With NeedDeps we need to load at least direct dependencies.
-		// NeedImports is used to ask for the direct dependencies.
+	if loadMode&(NeedDeps|NeedTypes|NeedTypesInfo) != 0 {
+		// All these things require knowing the import graph.
 		loadMode |= NeedImports
 	}
 
@@ -1240,5 +1269,5 @@ func impliedLoadMode(loadMode LoadMode) LoadMode {
 }
 
 func usesExportData(cfg *Config) bool {
-	return cfg.Mode&NeedExportsFile != 0 || cfg.Mode&NeedTypes != 0 && cfg.Mode&NeedDeps == 0
+	return cfg.Mode&NeedExportFile != 0 || cfg.Mode&NeedTypes != 0 && cfg.Mode&NeedDeps == 0
 }

vendor/golang.org/x/tools/imports/forward.go

@@ -40,7 +40,7 @@ var LocalPrefix string
 //
 // Note that filename's directory influences which imports can be chosen,
 // so it is important that filename be accurate.
-// To process data ``as if'' it were in filename, pass the data as a non-nil src.
+// To process data “as if” it were in filename, pass the data as a non-nil src.
 func Process(filename string, src []byte, opt *Options) ([]byte, error) {
 	var err error
 	if src == nil {

vendor/golang.org/x/tools/internal/fastwalk/fastwalk.go

@@ -40,12 +40,12 @@ var ErrSkipFiles = errors.New("fastwalk: skip remaining files in directory")
 // If fastWalk returns filepath.SkipDir, the directory is skipped.
 //
 // Unlike filepath.Walk:
-//   * file stat calls must be done by the user.
+//   - file stat calls must be done by the user.
 //     The only provided metadata is the file type, which does not include
 //     any permission bits.
-//   * multiple goroutines stat the filesystem concurrently. The provided
+//   - multiple goroutines stat the filesystem concurrently. The provided
 //     walkFn must be safe for concurrent use.
-//   * fastWalk can follow symlinks if walkFn returns the TraverseLink
+//   - fastWalk can follow symlinks if walkFn returns the TraverseLink
 //     sentinel error. It is the walkFn's responsibility to prevent
 //     fastWalk from going into symlink cycles.
 func Walk(root string, walkFn func(path string, typ os.FileMode) error) error {

vendor/golang.org/x/tools/internal/gocommand/invoke.go

@@ -264,8 +264,10 @@ func cmdDebugStr(cmd *exec.Cmd) string {
 	env := make(map[string]string)
 	for _, kv := range cmd.Env {
 		split := strings.SplitN(kv, "=", 2)
-		k, v := split[0], split[1]
-		env[k] = v
+		if len(split) == 2 {
+			k, v := split[0], split[1]
+			env[k] = v
+		}
 	}
 
 	var args []string

vendor/golang.org/x/tools/internal/gopathwalk/walk.go

@@ -175,8 +175,8 @@ func (w *walker) shouldSkipDir(fi os.FileInfo, dir string) bool {
 
 // walk walks through the given path.
 func (w *walker) walk(path string, typ os.FileMode) error {
-	dir := filepath.Dir(path)
 	if typ.IsRegular() {
+		dir := filepath.Dir(path)
 		if dir == w.root.Path && (w.root.Type == RootGOROOT || w.root.Type == RootGOPATH) {
 			// Doesn't make sense to have regular files
 			// directly in your $GOPATH/src or $GOROOT/src.
@@ -209,12 +209,7 @@ func (w *walker) walk(path string, typ os.FileMode) error {
 			// Emacs noise.
 			return nil
 		}
-		fi, err := os.Lstat(path)
-		if err != nil {
-			// Just ignore it.
-			return nil
-		}
-		if w.shouldTraverse(dir, fi) {
+		if w.shouldTraverse(path) {
 			return fastwalk.ErrTraverseLink
 		}
 	}
@@ -224,13 +219,8 @@ func (w *walker) walk(path string, typ os.FileMode) error {
 // shouldTraverse reports whether the symlink fi, found in dir,
 // should be followed.  It makes sure symlinks were never visited
 // before to avoid symlink loops.
-func (w *walker) shouldTraverse(dir string, fi os.FileInfo) bool {
-	path := filepath.Join(dir, fi.Name())
-	target, err := filepath.EvalSymlinks(path)
-	if err != nil {
-		return false
-	}
-	ts, err := os.Stat(target)
+func (w *walker) shouldTraverse(path string) bool {
+	ts, err := os.Stat(path)
 	if err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		return false
@@ -238,7 +228,7 @@ func (w *walker) shouldTraverse(dir string, fi os.FileInfo) bool {
 	if !ts.IsDir() {
 		return false
 	}
-	if w.shouldSkipDir(ts, dir) {
+	if w.shouldSkipDir(ts, filepath.Dir(path)) {
 		return false
 	}
 	// Check for symlink loops by statting each directory component

vendor/golang.org/x/tools/internal/imports/fix.go

@@ -796,7 +796,7 @@ func GetPackageExports(ctx context.Context, wrapped func(PackageExport), searchP
 	return getCandidatePkgs(ctx, callback, filename, filePkg, env)
 }
 
-var RequiredGoEnvVars = []string{"GO111MODULE", "GOFLAGS", "GOINSECURE", "GOMOD", "GOMODCACHE", "GONOPROXY", "GONOSUMDB", "GOPATH", "GOPROXY", "GOROOT", "GOSUMDB"}
+var RequiredGoEnvVars = []string{"GO111MODULE", "GOFLAGS", "GOINSECURE", "GOMOD", "GOMODCACHE", "GONOPROXY", "GONOSUMDB", "GOPATH", "GOPROXY", "GOROOT", "GOSUMDB", "GOWORK"}
 
 // ProcessEnv contains environment variables and settings that affect the use of
 // the go command, the go/build package, etc.
@@ -906,7 +906,7 @@ func (e *ProcessEnv) GetResolver() (Resolver, error) {
 	if err := e.init(); err != nil {
 		return nil, err
 	}
-	if len(e.Env["GOMOD"]) == 0 {
+	if len(e.Env["GOMOD"]) == 0 && len(e.Env["GOWORK"]) == 0 {
 		e.resolver = newGopathResolver(e)
 		return e.resolver, nil
 	}

vendor/golang.org/x/tools/internal/imports/imports.go

@@ -103,12 +103,17 @@ func ApplyFixes(fixes []*ImportFix, filename string, src []byte, opt *Options, e
 	return formatFile(fileSet, file, src, nil, opt)
 }
 
-func formatFile(fileSet *token.FileSet, file *ast.File, src []byte, adjust func(orig []byte, src []byte) []byte, opt *Options) ([]byte, error) {
-	mergeImports(fileSet, file)
-	sortImports(opt.LocalPrefix, fileSet, file)
-	imps := astutil.Imports(fileSet, file)
+// formatFile formats the file syntax tree.
+// It may mutate the token.FileSet.
+//
+// If an adjust function is provided, it is called after formatting
+// with the original source (formatFile's src parameter) and the
+// formatted file, and returns the postpocessed result.
+func formatFile(fset *token.FileSet, file *ast.File, src []byte, adjust func(orig []byte, src []byte) []byte, opt *Options) ([]byte, error) {
+	mergeImports(file)
+	sortImports(opt.LocalPrefix, fset.File(file.Pos()), file)
 	var spacesBefore []string // import paths we need spaces before
-	for _, impSection := range imps {
+	for _, impSection := range astutil.Imports(fset, file) {
 		// Within each block of contiguous imports, see if any
 		// import lines are in different group numbers. If so,
 		// we'll need to put a space between them so it's
@@ -132,7 +137,7 @@ func formatFile(fileSet *token.FileSet, file *ast.File, src []byte, adjust func(
 	printConfig := &printer.Config{Mode: printerMode, Tabwidth: opt.TabWidth}
 
 	var buf bytes.Buffer
-	err := printConfig.Fprint(&buf, fileSet, file)
+	err := printConfig.Fprint(&buf, fset, file)
 	if err != nil {
 		return nil, err
 	}
@@ -276,11 +281,11 @@ func cutSpace(b []byte) (before, middle, after []byte) {
 }
 
 // matchSpace reformats src to use the same space context as orig.
-// 1) If orig begins with blank lines, matchSpace inserts them at the beginning of src.
-// 2) matchSpace copies the indentation of the first non-blank line in orig
-//    to every non-blank line in src.
-// 3) matchSpace copies the trailing space from orig and uses it in place
-//   of src's trailing space.
+//  1. If orig begins with blank lines, matchSpace inserts them at the beginning of src.
+//  2. matchSpace copies the indentation of the first non-blank line in orig
+//     to every non-blank line in src.
+//  3. matchSpace copies the trailing space from orig and uses it in place
+//     of src's trailing space.
 func matchSpace(orig []byte, src []byte) []byte {
 	before, _, after := cutSpace(orig)
 	i := bytes.LastIndex(before, []byte{'\n'})

vendor/golang.org/x/tools/internal/imports/mod.go

@@ -70,9 +70,17 @@ func (r *ModuleResolver) init() error {
 		Logf:       r.env.Logf,
 		WorkingDir: r.env.WorkingDir,
 	}
-	vendorEnabled, mainModVendor, err := gocommand.VendorEnabled(context.TODO(), inv, r.env.GocmdRunner)
-	if err != nil {
-		return err
+
+	vendorEnabled := false
+	var mainModVendor *gocommand.ModuleJSON
+
+	// Module vendor directories are ignored in workspace mode:
+	// https://go.googlesource.com/proposal/+/master/design/45713-workspace.md
+	if len(r.env.Env["GOWORK"]) == 0 {
+		vendorEnabled, mainModVendor, err = gocommand.VendorEnabled(context.TODO(), inv, r.env.GocmdRunner)
+		if err != nil {
+			return err
+		}
 	}
 
 	if mainModVendor != nil && vendorEnabled {

vendor/golang.org/x/tools/internal/imports/sortimports.go

@@ -3,6 +3,7 @@
 // license that can be found in the LICENSE file.
 
 // Hacked up copy of go/ast/import.go
+// Modified to use a single token.File in preference to a FileSet.
 
 package imports
 
@@ -16,7 +17,9 @@ import (
 
 // sortImports sorts runs of consecutive import lines in import blocks in f.
 // It also removes duplicate imports when it is possible to do so without data loss.
-func sortImports(localPrefix string, fset *token.FileSet, f *ast.File) {
+//
+// It may mutate the token.File.
+func sortImports(localPrefix string, tokFile *token.File, f *ast.File) {
 	for i, d := range f.Decls {
 		d, ok := d.(*ast.GenDecl)
 		if !ok || d.Tok != token.IMPORT {
@@ -39,21 +42,21 @@ func sortImports(localPrefix string, fset *token.FileSet, f *ast.File) {
 		i := 0
 		specs := d.Specs[:0]
 		for j, s := range d.Specs {
-			if j > i && fset.Position(s.Pos()).Line > 1+fset.Position(d.Specs[j-1].End()).Line {
+			if j > i && tokFile.Line(s.Pos()) > 1+tokFile.Line(d.Specs[j-1].End()) {
 				// j begins a new run.  End this one.
-				specs = append(specs, sortSpecs(localPrefix, fset, f, d.Specs[i:j])...)
+				specs = append(specs, sortSpecs(localPrefix, tokFile, f, d.Specs[i:j])...)
 				i = j
 			}
 		}
-		specs = append(specs, sortSpecs(localPrefix, fset, f, d.Specs[i:])...)
+		specs = append(specs, sortSpecs(localPrefix, tokFile, f, d.Specs[i:])...)
 		d.Specs = specs
 
 		// Deduping can leave a blank line before the rparen; clean that up.
 		if len(d.Specs) > 0 {
 			lastSpec := d.Specs[len(d.Specs)-1]
-			lastLine := fset.Position(lastSpec.Pos()).Line
-			if rParenLine := fset.Position(d.Rparen).Line; rParenLine > lastLine+1 {
-				fset.File(d.Rparen).MergeLine(rParenLine - 1)
+			lastLine := tokFile.PositionFor(lastSpec.Pos(), false).Line
+			if rParenLine := tokFile.PositionFor(d.Rparen, false).Line; rParenLine > lastLine+1 {
+				tokFile.MergeLine(rParenLine - 1) // has side effects!
 			}
 		}
 	}
@@ -62,7 +65,7 @@ func sortImports(localPrefix string, fset *token.FileSet, f *ast.File) {
 // mergeImports merges all the import declarations into the first one.
 // Taken from golang.org/x/tools/ast/astutil.
 // This does not adjust line numbers properly
-func mergeImports(fset *token.FileSet, f *ast.File) {
+func mergeImports(f *ast.File) {
 	if len(f.Decls) <= 1 {
 		return
 	}
@@ -144,7 +147,9 @@ type posSpan struct {
 	End   token.Pos
 }
 
-func sortSpecs(localPrefix string, fset *token.FileSet, f *ast.File, specs []ast.Spec) []ast.Spec {
+// sortSpecs sorts the import specs within each import decl.
+// It may mutate the token.File.
+func sortSpecs(localPrefix string, tokFile *token.File, f *ast.File, specs []ast.Spec) []ast.Spec {
 	// Can't short-circuit here even if specs are already sorted,
 	// since they might yet need deduplication.
 	// A lone import, however, may be safely ignored.
@@ -160,7 +165,7 @@ func sortSpecs(localPrefix string, fset *token.FileSet, f *ast.File, specs []ast
 
 	// Identify comments in this range.
 	// Any comment from pos[0].Start to the final line counts.
-	lastLine := fset.Position(pos[len(pos)-1].End).Line
+	lastLine := tokFile.Line(pos[len(pos)-1].End)
 	cstart := len(f.Comments)
 	cend := len(f.Comments)
 	for i, g := range f.Comments {
@@ -170,7 +175,7 @@ func sortSpecs(localPrefix string, fset *token.FileSet, f *ast.File, specs []ast
 		if i < cstart {
 			cstart = i
 		}
-		if fset.Position(g.End()).Line > lastLine {
+		if tokFile.Line(g.End()) > lastLine {
 			cend = i
 			break
 		}
@@ -203,7 +208,7 @@ func sortSpecs(localPrefix string, fset *token.FileSet, f *ast.File, specs []ast
 			deduped = append(deduped, s)
 		} else {
 			p := s.Pos()
-			fset.File(p).MergeLine(fset.Position(p).Line)
+			tokFile.MergeLine(tokFile.Line(p)) // has side effects!
 		}
 	}
 	specs = deduped
@@ -234,21 +239,21 @@ func sortSpecs(localPrefix string, fset *token.FileSet, f *ast.File, specs []ast
 
 	// Fixup comments can insert blank lines, because import specs are on different lines.
 	// We remove those blank lines here by merging import spec to the first import spec line.
-	firstSpecLine := fset.Position(specs[0].Pos()).Line
+	firstSpecLine := tokFile.Line(specs[0].Pos())
 	for _, s := range specs[1:] {
 		p := s.Pos()
-		line := fset.File(p).Line(p)
+		line := tokFile.Line(p)
 		for previousLine := line - 1; previousLine >= firstSpecLine; {
 			// MergeLine can panic. Avoid the panic at the cost of not removing the blank line
 			// golang/go#50329
-			if previousLine > 0 && previousLine < fset.File(p).LineCount() {
-				fset.File(p).MergeLine(previousLine)
+			if previousLine > 0 && previousLine < tokFile.LineCount() {
+				tokFile.MergeLine(previousLine) // has side effects!
 				previousLine--
 			} else {
 				// try to gather some data to diagnose how this could happen
 				req := "Please report what the imports section of your go file looked like."
 				log.Printf("panic avoided: first:%d line:%d previous:%d max:%d. %s",
-					firstSpecLine, line, previousLine, fset.File(p).LineCount(), req)
+					firstSpecLine, line, previousLine, tokFile.LineCount(), req)
 			}
 		}
 	}

vendor/golang.org/x/tools/internal/imports/zstdlib.go

@@ -88,6 +88,7 @@ var stdlib = map[string][]string{
 		"ContainsAny",
 		"ContainsRune",
 		"Count",
+		"Cut",
 		"Equal",
 		"EqualFold",
 		"ErrTooLarge",
@@ -711,6 +712,11 @@ var stdlib = map[string][]string{
 		"ValueConverter",
 		"Valuer",
 	},
+	"debug/buildinfo": []string{
+		"BuildInfo",
+		"Read",
+		"ReadFile",
+	},
 	"debug/dwarf": []string{
 		"AddrType",
 		"ArrayType",
@@ -1944,6 +1950,7 @@ var stdlib = map[string][]string{
 		"R_PPC64_REL24_NOTOC",
 		"R_PPC64_REL32",
 		"R_PPC64_REL64",
+		"R_PPC64_RELATIVE",
 		"R_PPC64_SECTOFF_DS",
 		"R_PPC64_SECTOFF_LO_DS",
 		"R_PPC64_TLS",
@@ -2547,6 +2554,7 @@ var stdlib = map[string][]string{
 		"Symbol",
 	},
 	"debug/plan9obj": []string{
+		"ErrNoSymbols",
 		"File",
 		"FileHeader",
 		"Magic386",
@@ -2906,6 +2914,7 @@ var stdlib = map[string][]string{
 		"Importer",
 		"IncDecStmt",
 		"IndexExpr",
+		"IndexListExpr",
 		"Inspect",
 		"InterfaceType",
 		"IsExported",
@@ -3179,6 +3188,7 @@ var stdlib = map[string][]string{
 		"SUB",
 		"SUB_ASSIGN",
 		"SWITCH",
+		"TILDE",
 		"TYPE",
 		"Token",
 		"UnaryPrec",
@@ -3187,6 +3197,7 @@ var stdlib = map[string][]string{
 		"XOR_ASSIGN",
 	},
 	"go/types": []string{
+		"ArgumentError",
 		"Array",
 		"AssertableTo",
 		"AssignableTo",
@@ -3205,6 +3216,7 @@ var stdlib = map[string][]string{
 		"Complex64",
 		"Config",
 		"Const",
+		"Context",
 		"ConvertibleTo",
 		"DefPredeclaredTestFuncs",
 		"Default",
@@ -3224,6 +3236,8 @@ var stdlib = map[string][]string{
 		"ImporterFrom",
 		"Info",
 		"Initializer",
+		"Instance",
+		"Instantiate",
 		"Int",
 		"Int16",
 		"Int32",
@@ -3254,6 +3268,7 @@ var stdlib = map[string][]string{
 		"NewChan",
 		"NewChecker",
 		"NewConst",
+		"NewContext",
 		"NewField",
 		"NewFunc",
 		"NewInterface",
@@ -3268,10 +3283,14 @@ var stdlib = map[string][]string{
 		"NewPointer",
 		"NewScope",
 		"NewSignature",
+		"NewSignatureType",
 		"NewSlice",
 		"NewStruct",
+		"NewTerm",
 		"NewTuple",
 		"NewTypeName",
+		"NewTypeParam",
+		"NewUnion",
 		"NewVar",
 		"Nil",
 		"Object",
@@ -3296,11 +3315,15 @@ var stdlib = map[string][]string{
 		"StdSizes",
 		"String",
 		"Struct",
+		"Term",
 		"Tuple",
 		"Typ",
 		"Type",
 		"TypeAndValue",
+		"TypeList",
 		"TypeName",
+		"TypeParam",
+		"TypeParamList",
 		"TypeString",
 		"Uint",
 		"Uint16",
@@ -3308,6 +3331,7 @@ var stdlib = map[string][]string{
 		"Uint64",
 		"Uint8",
 		"Uintptr",
+		"Union",
 		"Universe",
 		"Unsafe",
 		"UnsafePointer",
@@ -4080,9 +4104,11 @@ var stdlib = map[string][]string{
 		"SRV",
 		"SplitHostPort",
 		"TCPAddr",
+		"TCPAddrFromAddrPort",
 		"TCPConn",
 		"TCPListener",
 		"UDPAddr",
+		"UDPAddrFromAddrPort",
 		"UDPConn",
 		"UnixAddr",
 		"UnixConn",
@@ -4142,6 +4168,7 @@ var stdlib = map[string][]string{
 		"ListenAndServe",
 		"ListenAndServeTLS",
 		"LocalAddrContextKey",
+		"MaxBytesHandler",
 		"MaxBytesReader",
 		"MethodConnect",
 		"MethodDelete",
@@ -4338,6 +4365,25 @@ var stdlib = map[string][]string{
 		"ParseDate",
 		"ReadMessage",
 	},
+	"net/netip": []string{
+		"Addr",
+		"AddrFrom16",
+		"AddrFrom4",
+		"AddrFromSlice",
+		"AddrPort",
+		"AddrPortFrom",
+		"IPv4Unspecified",
+		"IPv6LinkLocalAllNodes",
+		"IPv6Unspecified",
+		"MustParseAddr",
+		"MustParseAddrPort",
+		"MustParsePrefix",
+		"ParseAddr",
+		"ParseAddrPort",
+		"ParsePrefix",
+		"Prefix",
+		"PrefixFrom",
+	},
 	"net/rpc": []string{
 		"Accept",
 		"Call",
@@ -4641,6 +4687,8 @@ var stdlib = map[string][]string{
 		"Method",
 		"New",
 		"NewAt",
+		"Pointer",
+		"PointerTo",
 		"Ptr",
 		"PtrTo",
 		"RecvDir",
@@ -4819,9 +4867,11 @@ var stdlib = map[string][]string{
 	},
 	"runtime/debug": []string{
 		"BuildInfo",
+		"BuildSetting",
 		"FreeOSMemory",
 		"GCStats",
 		"Module",
+		"ParseBuildInfo",
 		"PrintStack",
 		"ReadBuildInfo",
 		"ReadGCStats",
@@ -4939,11 +4989,13 @@ var stdlib = map[string][]string{
 	},
 	"strings": []string{
 		"Builder",
+		"Clone",
 		"Compare",
 		"Contains",
 		"ContainsAny",
 		"ContainsRune",
 		"Count",
+		"Cut",
 		"EqualFold",
 		"Fields",
 		"FieldsFunc",
@@ -9793,6 +9845,7 @@ var stdlib = map[string][]string{
 		"Syscall18",
 		"Syscall6",
 		"Syscall9",
+		"SyscallN",
 		"Sysctl",
 		"SysctlUint32",
 		"Sysctlnode",
@@ -10202,7 +10255,6 @@ var stdlib = map[string][]string{
 		"Value",
 		"ValueError",
 		"ValueOf",
-		"Wrapper",
 	},
 	"testing": []string{
 		"AllocsPerRun",
@@ -10213,9 +10265,11 @@ var stdlib = map[string][]string{
 		"CoverBlock",
 		"CoverMode",
 		"Coverage",
+		"F",
 		"Init",
 		"InternalBenchmark",
 		"InternalExample",
+		"InternalFuzzTarget",
 		"InternalTest",
 		"M",
 		"Main",
@@ -10313,9 +10367,11 @@ var stdlib = map[string][]string{
 		"ActionNode",
 		"BoolNode",
 		"BranchNode",
+		"BreakNode",
 		"ChainNode",
 		"CommandNode",
 		"CommentNode",
+		"ContinueNode",
 		"DotNode",
 		"FieldNode",
 		"IdentifierNode",
@@ -10329,9 +10385,11 @@ var stdlib = map[string][]string{
 		"Node",
 		"NodeAction",
 		"NodeBool",
+		"NodeBreak",
 		"NodeChain",
 		"NodeCommand",
 		"NodeComment",
+		"NodeContinue",
 		"NodeDot",
 		"NodeField",
 		"NodeIdentifier",
@@ -10727,6 +10785,7 @@ var stdlib = map[string][]string{
 		"IsSurrogate",
 	},
 	"unicode/utf8": []string{
+		"AppendRune",
 		"DecodeLastRune",
 		"DecodeLastRuneInString",
 		"DecodeRune",

vendor/golang.org/x/tools/internal/packagesinternal/packages.go

@@ -23,6 +23,8 @@ var GetGoCmdRunner = func(config interface{}) *gocommand.Runner { return nil }
 var SetGoCmdRunner = func(config interface{}, runner *gocommand.Runner) {}
 
 var TypecheckCgo int
+var DepsErrors int // must be set as a LoadMode to call GetDepsErrors
+var ForTest int    // must be set as a LoadMode to call GetForTest
 
 var SetModFlag = func(config interface{}, value string) {}
 var SetModFile = func(config interface{}, value string) {}

vendor/golang.org/x/tools/internal/typeparams/common.go

@@ -16,11 +16,10 @@
 // Additionally, this package contains common utilities for working with the
 // new generic constructs, to supplement the standard library APIs. Notably,
 // the StructuralTerms API computes a minimal representation of the structural
-// restrictions on a type parameter. In the future, this API may be available
-// from go/types.
+// restrictions on a type parameter.
 //
-// See the example/README.md for a more detailed guide on how to update tools
-// to support generics.
+// An external version of these APIs is available in the
+// golang.org/x/exp/typeparams module.
 package typeparams
 
 import (
@@ -121,15 +120,15 @@ func OriginMethod(fn *types.Func) *types.Func {
 //
 // For example, consider the following type declarations:
 //
-//  type Interface[T any] interface {
-//  	Accept(T)
-//  }
+//	type Interface[T any] interface {
+//		Accept(T)
+//	}
 //
-//  type Container[T any] struct {
-//  	Element T
-//  }
+//	type Container[T any] struct {
+//		Element T
+//	}
 //
-//  func (c Container[T]) Accept(t T) { c.Element = t }
+//	func (c Container[T]) Accept(t T) { c.Element = t }
 //
 // In this case, GenericAssignableTo reports that instantiations of Container
 // are assignable to the corresponding instantiation of Interface.

vendor/golang.org/x/tools/internal/typeparams/coretype.go

@@ -0,0 +1,122 @@
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package typeparams
+
+import (
+	"go/types"
+)
+
+// CoreType returns the core type of T or nil if T does not have a core type.
+//
+// See https://go.dev/ref/spec#Core_types for the definition of a core type.
+func CoreType(T types.Type) types.Type {
+	U := T.Underlying()
+	if _, ok := U.(*types.Interface); !ok {
+		return U // for non-interface types,
+	}
+
+	terms, err := _NormalTerms(U)
+	if len(terms) == 0 || err != nil {
+		// len(terms) -> empty type set of interface.
+		// err != nil => U is invalid, exceeds complexity bounds, or has an empty type set.
+		return nil // no core type.
+	}
+
+	U = terms[0].Type().Underlying()
+	var identical int // i in [0,identical) => Identical(U, terms[i].Type().Underlying())
+	for identical = 1; identical < len(terms); identical++ {
+		if !types.Identical(U, terms[identical].Type().Underlying()) {
+			break
+		}
+	}
+
+	if identical == len(terms) {
+		// https://go.dev/ref/spec#Core_types
+		// "There is a single type U which is the underlying type of all types in the type set of T"
+		return U
+	}
+	ch, ok := U.(*types.Chan)
+	if !ok {
+		return nil // no core type as identical < len(terms) and U is not a channel.
+	}
+	// https://go.dev/ref/spec#Core_types
+	// "the type chan E if T contains only bidirectional channels, or the type chan<- E or
+	// <-chan E depending on the direction of the directional channels present."
+	for chans := identical; chans < len(terms); chans++ {
+		curr, ok := terms[chans].Type().Underlying().(*types.Chan)
+		if !ok {
+			return nil
+		}
+		if !types.Identical(ch.Elem(), curr.Elem()) {
+			return nil // channel elements are not identical.
+		}
+		if ch.Dir() == types.SendRecv {
+			// ch is bidirectional. We can safely always use curr's direction.
+			ch = curr
+		} else if curr.Dir() != types.SendRecv && ch.Dir() != curr.Dir() {
+			// ch and curr are not bidirectional and not the same direction.
+			return nil
+		}
+	}
+	return ch
+}
+
+// _NormalTerms returns a slice of terms representing the normalized structural
+// type restrictions of a type, if any.
+//
+// For all types other than *types.TypeParam, *types.Interface, and
+// *types.Union, this is just a single term with Tilde() == false and
+// Type() == typ. For *types.TypeParam, *types.Interface, and *types.Union, see
+// below.
+//
+// Structural type restrictions of a type parameter are created via
+// non-interface types embedded in its constraint interface (directly, or via a
+// chain of interface embeddings). For example, in the declaration type
+// T[P interface{~int; m()}] int the structural restriction of the type
+// parameter P is ~int.
+//
+// With interface embedding and unions, the specification of structural type
+// restrictions may be arbitrarily complex. For example, consider the
+// following:
+//
+//  type A interface{ ~string|~[]byte }
+//
+//  type B interface{ int|string }
+//
+//  type C interface { ~string|~int }
+//
+//  type T[P interface{ A|B; C }] int
+//
+// In this example, the structural type restriction of P is ~string|int: A|B
+// expands to ~string|~[]byte|int|string, which reduces to ~string|~[]byte|int,
+// which when intersected with C (~string|~int) yields ~string|int.
+//
+// _NormalTerms computes these expansions and reductions, producing a
+// "normalized" form of the embeddings. A structural restriction is normalized
+// if it is a single union containing no interface terms, and is minimal in the
+// sense that removing any term changes the set of types satisfying the
+// constraint. It is left as a proof for the reader that, modulo sorting, there
+// is exactly one such normalized form.
+//
+// Because the minimal representation always takes this form, _NormalTerms
+// returns a slice of tilde terms corresponding to the terms of the union in
+// the normalized structural restriction. An error is returned if the type is
+// invalid, exceeds complexity bounds, or has an empty type set. In the latter
+// case, _NormalTerms returns ErrEmptyTypeSet.
+//
+// _NormalTerms makes no guarantees about the order of terms, except that it
+// is deterministic.
+func _NormalTerms(typ types.Type) ([]*Term, error) {
+	switch typ := typ.(type) {
+	case *TypeParam:
+		return StructuralTerms(typ)
+	case *Union:
+		return UnionTermSet(typ)
+	case *types.Interface:
+		return InterfaceTermSet(typ)
+	default:
+		return []*Term{NewTerm(false, typ)}, nil
+	}
+}

vendor/golang.org/x/tools/internal/typeparams/normalize.go

@@ -24,20 +24,22 @@ var ErrEmptyTypeSet = errors.New("empty type set")
 // Structural type restrictions of a type parameter are created via
 // non-interface types embedded in its constraint interface (directly, or via a
 // chain of interface embeddings). For example, in the declaration
-//  type T[P interface{~int; m()}] int
+//
+//	type T[P interface{~int; m()}] int
+//
 // the structural restriction of the type parameter P is ~int.
 //
 // With interface embedding and unions, the specification of structural type
 // restrictions may be arbitrarily complex. For example, consider the
 // following:
 //
-//  type A interface{ ~string|~[]byte }
+//	type A interface{ ~string|~[]byte }
 //
-//  type B interface{ int|string }
+//	type B interface{ int|string }
 //
-//  type C interface { ~string|~int }
+//	type C interface { ~string|~int }
 //
-//  type T[P interface{ A|B; C }] int
+//	type T[P interface{ A|B; C }] int
 //
 // In this example, the structural type restriction of P is ~string|int: A|B
 // expands to ~string|~[]byte|int|string, which reduces to ~string|~[]byte|int,

vendor/golang.org/x/tools/internal/typeparams/termlist.go

@@ -97,15 +97,6 @@ func (xl termlist) norm() termlist {
 	return rl
 }
 
-// If the type set represented by xl is specified by a single (non-𝓤) term,
-// structuralType returns that type. Otherwise it returns nil.
-func (xl termlist) structuralType() types.Type {
-	if nl := xl.norm(); len(nl) == 1 {
-		return nl[0].typ // if nl.isAll() then typ is nil, which is ok
-	}
-	return nil
-}
-
 // union returns the union xl ∪ yl.
 func (xl termlist) union(yl termlist) termlist {
 	return append(xl, yl...).norm()