update to latest golang.org/x/crypto

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

@@ -27,10 +27,9 @@ import (
 	"go/token"
 	"go/types"
 	"io"
-	"io/ioutil"
 	"os/exec"
 
-	"golang.org/x/tools/go/internal/gcimporter"
+	"golang.org/x/tools/internal/gcimporter"
 )
 
 // Find returns the name of an object (.o) or archive (.a) file
@@ -85,9 +84,26 @@ func NewReader(r io.Reader) (io.Reader, error) {
 	}
 }
 
+// readAll works the same way as io.ReadAll, but avoids allocations and copies
+// by preallocating a byte slice of the necessary size if the size is known up
+// front. This is always possible when the input is an archive. In that case,
+// NewReader will return the known size using an io.LimitedReader.
+func readAll(r io.Reader) ([]byte, error) {
+	if lr, ok := r.(*io.LimitedReader); ok {
+		data := make([]byte, lr.N)
+		_, err := io.ReadFull(lr, data)
+		return data, err
+	}
+	return io.ReadAll(r)
+}
+
 // Read reads export data from in, decodes it, and returns type
 // information for the package.
-// The package name is specified by path.
+//
+// The package path (effectively its linker symbol prefix) is
+// specified by path, since unlike the package name, this information
+// may not be recorded in the export data.
+//
 // File position information is added to fset.
 //
 // Read may inspect and add to the imports map to ensure that references
@@ -98,7 +114,7 @@ func NewReader(r io.Reader) (io.Reader, error) {
 //
 // On return, the state of the reader is undefined.
 func Read(in io.Reader, fset *token.FileSet, imports map[string]*types.Package, path string) (*types.Package, error) {
-	data, err := ioutil.ReadAll(in)
+	data, err := readAll(in)
 	if err != nil {
 		return nil, fmt.Errorf("reading export data for %q: %v", path, err)
 	}
@@ -107,12 +123,6 @@ func Read(in io.Reader, fset *token.FileSet, imports map[string]*types.Package,
 		return nil, fmt.Errorf("can't read export data for %q directly from an archive file (call gcexportdata.NewReader first to extract export data)", path)
 	}
 
-	// The App Engine Go runtime v1.6 uses the old export data format.
-	// TODO(adonovan): delete once v1.7 has been around for a while.
-	if bytes.HasPrefix(data, []byte("package ")) {
-		return gcimporter.ImportData(imports, path, path, bytes.NewReader(data))
-	}
-
 	// 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.
@@ -161,7 +171,7 @@ func Write(out io.Writer, fset *token.FileSet, pkg *types.Package) error {
 //
 // Experimental: This API is experimental and may change in the future.
 func ReadBundle(in io.Reader, fset *token.FileSet, imports map[string]*types.Package) ([]*types.Package, error) {
-	data, err := ioutil.ReadAll(in)
+	data, err := readAll(in)
 	if err != nil {
 		return nil, fmt.Errorf("reading export bundle: %v", err)
 	}

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

@@ -60,6 +60,7 @@ func (r *responseDeduper) addAll(dr *driverResponse) {
 	for _, root := range dr.Roots {
 		r.addRoot(root)
 	}
+	r.dr.GoVersion = dr.GoVersion
 }
 
 func (r *responseDeduper) addPackage(p *Package) {
@@ -454,11 +455,14 @@ func (state *golistState) createDriverResponse(words ...string) (*driverResponse
 	if err != nil {
 		return nil, err
 	}
+
 	seen := make(map[string]*jsonPackage)
 	pkgs := make(map[string]*Package)
 	additionalErrors := make(map[string][]Error)
 	// Decode the JSON and convert it to Package form.
-	var response driverResponse
+	response := &driverResponse{
+		GoVersion: goVersion,
+	}
 	for dec := json.NewDecoder(buf); dec.More(); {
 		p := new(jsonPackage)
 		if err := dec.Decode(p); err != nil {
@@ -600,17 +604,12 @@ func (state *golistState) createDriverResponse(words ...string) (*driverResponse
 
 		// Work around https://golang.org/issue/28749:
 		// cmd/go puts assembly, C, and C++ files in CompiledGoFiles.
-		// Filter out any elements of CompiledGoFiles that are also in OtherFiles.
-		// We have to keep this workaround in place until go1.12 is a distant memory.
-		if len(pkg.OtherFiles) > 0 {
-			other := make(map[string]bool, len(pkg.OtherFiles))
-			for _, f := range pkg.OtherFiles {
-				other[f] = true
-			}
-
+		// Remove files from CompiledGoFiles that are non-go files
+		// (or are not files that look like they are from the cache).
+		if len(pkg.CompiledGoFiles) > 0 {
 			out := pkg.CompiledGoFiles[:0]
 			for _, f := range pkg.CompiledGoFiles {
-				if other[f] {
+				if ext := filepath.Ext(f); ext != ".go" && ext != "" { // ext == "" means the file is from the cache, so probably cgo-processed file
 					continue
 				}
 				out = append(out, f)
@@ -730,7 +729,7 @@ func (state *golistState) createDriverResponse(words ...string) (*driverResponse
 	}
 	sort.Slice(response.Packages, func(i, j int) bool { return response.Packages[i].ID < response.Packages[j].ID })
 
-	return &response, nil
+	return response, nil
 }
 
 func (state *golistState) shouldAddFilenameFromError(p *jsonPackage) bool {
@@ -756,6 +755,7 @@ func (state *golistState) shouldAddFilenameFromError(p *jsonPackage) bool {
 	return len(p.Error.ImportStack) == 0 || p.Error.ImportStack[len(p.Error.ImportStack)-1] == p.ImportPath
 }
 
+// getGoVersion returns the effective minor version of the go command.
 func (state *golistState) getGoVersion() (int, error) {
 	state.goVersionOnce.Do(func() {
 		state.goVersion, state.goVersionError = gocommand.GoVersion(state.ctx, state.cfgInvocation(), state.cfg.gocmdRunner)

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

@@ -15,10 +15,12 @@ import (
 	"go/scanner"
 	"go/token"
 	"go/types"
+	"io"
 	"io/ioutil"
 	"log"
 	"os"
 	"path/filepath"
+	"runtime"
 	"strings"
 	"sync"
 	"time"
@@ -233,6 +235,11 @@ type driverResponse struct {
 	// Imports will be connected and then type and syntax information added in a
 	// later pass (see refine).
 	Packages []*Package
+
+	// GoVersion is the minor version number used by the driver
+	// (e.g. the go command on the PATH) when selecting .go files.
+	// Zero means unknown.
+	GoVersion int
 }
 
 // Load loads and returns the Go packages named by the given patterns.
@@ -256,7 +263,7 @@ func Load(cfg *Config, patterns ...string) ([]*Package, error) {
 		return nil, err
 	}
 	l.sizes = response.Sizes
-	return l.refine(response.Roots, response.Packages...)
+	return l.refine(response)
 }
 
 // defaultDriver is a driver that implements go/packages' fallback behavior.
@@ -297,6 +304,9 @@ type Package struct {
 	// of the package, or while parsing or type-checking its files.
 	Errors []Error
 
+	// TypeErrors contains the subset of errors produced during type checking.
+	TypeErrors []types.Error
+
 	// GoFiles lists the absolute file paths of the package's Go source files.
 	GoFiles []string
 
@@ -532,6 +542,7 @@ type loaderPackage struct {
 	needsrc      bool  // load from source (Mode >= LoadTypes)
 	needtypes    bool  // type information is either requested or depended on
 	initial      bool  // package was matched by a pattern
+	goVersion    int   // minor version number of go command on PATH
 }
 
 // loader holds the working state of a single call to load.
@@ -618,7 +629,8 @@ func newLoader(cfg *Config) *loader {
 
 // refine connects the supplied packages into a graph and then adds type and
 // and syntax information as requested by the LoadMode.
-func (ld *loader) refine(roots []string, list ...*Package) ([]*Package, error) {
+func (ld *loader) refine(response *driverResponse) ([]*Package, error) {
+	roots := response.Roots
 	rootMap := make(map[string]int, len(roots))
 	for i, root := range roots {
 		rootMap[root] = i
@@ -626,7 +638,7 @@ func (ld *loader) refine(roots []string, list ...*Package) ([]*Package, error) {
 	ld.pkgs = make(map[string]*loaderPackage)
 	// first pass, fixup and build the map and roots
 	var initial = make([]*loaderPackage, len(roots))
-	for _, pkg := range list {
+	for _, pkg := range response.Packages {
 		rootIndex := -1
 		if i, found := rootMap[pkg.ID]; found {
 			rootIndex = i
@@ -648,6 +660,7 @@ func (ld *loader) refine(roots []string, list ...*Package) ([]*Package, error) {
 			Package:   pkg,
 			needtypes: needtypes,
 			needsrc:   needsrc,
+			goVersion: response.GoVersion,
 		}
 		ld.pkgs[lpkg.ID] = lpkg
 		if rootIndex >= 0 {
@@ -865,12 +878,19 @@ func (ld *loader) loadPackage(lpkg *loaderPackage) {
 	// never has to create a types.Package for an indirect dependency,
 	// which would then require that such created packages be explicitly
 	// inserted back into the Import graph as a final step after export data loading.
+	// (Hence this return is after the Types assignment.)
 	// The Diamond test exercises this case.
 	if !lpkg.needtypes && !lpkg.needsrc {
 		return
 	}
 	if !lpkg.needsrc {
-		ld.loadFromExportData(lpkg)
+		if err := ld.loadFromExportData(lpkg); err != nil {
+			lpkg.Errors = append(lpkg.Errors, Error{
+				Pos:  "-",
+				Msg:  err.Error(),
+				Kind: UnknownError, // e.g. can't find/open/parse export data
+			})
+		}
 		return // not a source package, don't get syntax trees
 	}
 
@@ -902,6 +922,7 @@ func (ld *loader) loadPackage(lpkg *loaderPackage) {
 
 		case types.Error:
 			// from type checker
+			lpkg.TypeErrors = append(lpkg.TypeErrors, err)
 			errs = append(errs, Error{
 				Pos:  err.Fset.Position(err.Pos).String(),
 				Msg:  err.Msg,
@@ -923,11 +944,41 @@ func (ld *loader) loadPackage(lpkg *loaderPackage) {
 		lpkg.Errors = append(lpkg.Errors, errs...)
 	}
 
+	// If the go command on the PATH is newer than the runtime,
+	// then the go/{scanner,ast,parser,types} packages from the
+	// standard library may be unable to process the files
+	// selected by go list.
+	//
+	// There is currently no way to downgrade the effective
+	// version of the go command (see issue 52078), so we proceed
+	// with the newer go command but, in case of parse or type
+	// errors, we emit an additional diagnostic.
+	//
+	// See:
+	// - golang.org/issue/52078 (flag to set release tags)
+	// - golang.org/issue/50825 (gopls legacy version support)
+	// - golang.org/issue/55883 (go/packages confusing error)
+	//
+	// Should we assert a hard minimum of (currently) go1.16 here?
+	var runtimeVersion int
+	if _, err := fmt.Sscanf(runtime.Version(), "go1.%d", &runtimeVersion); err == nil && runtimeVersion < lpkg.goVersion {
+		defer func() {
+			if len(lpkg.Errors) > 0 {
+				appendError(Error{
+					Pos:  "-",
+					Msg:  fmt.Sprintf("This application uses version go1.%d of the source-processing packages but runs version go1.%d of 'go list'. It may fail to process source files that rely on newer language features. If so, rebuild the application using a newer version of Go.", runtimeVersion, lpkg.goVersion),
+					Kind: UnknownError,
+				})
+			}
+		}()
+	}
+
 	if ld.Config.Mode&NeedTypes != 0 && len(lpkg.CompiledGoFiles) == 0 && lpkg.ExportFile != "" {
 		// The config requested loading sources and types, but sources are missing.
 		// Add an error to the package and fall back to loading from export data.
 		appendError(Error{"-", fmt.Sprintf("sources missing for package %s", lpkg.ID), ParseError})
-		ld.loadFromExportData(lpkg)
+		_ = ld.loadFromExportData(lpkg) // ignore any secondary errors
+
 		return // can't get syntax trees for this package
 	}
 
@@ -981,7 +1032,7 @@ func (ld *loader) loadPackage(lpkg *loaderPackage) {
 	tc := &types.Config{
 		Importer: importer,
 
-		// Type-check bodies of functions only in non-initial packages.
+		// Type-check bodies of functions only in initial packages.
 		// Example: for import graph A->B->C and initial packages {A,C},
 		// we can ignore function bodies in B.
 		IgnoreFuncBodies: ld.Mode&NeedDeps == 0 && !lpkg.initial,
@@ -1151,9 +1202,10 @@ func sameFile(x, y string) bool {
 	return false
 }
 
-// loadFromExportData returns type information for the specified
+// loadFromExportData ensures that type information is present for the specified
 // package, loading it from an export data file on the first request.
-func (ld *loader) loadFromExportData(lpkg *loaderPackage) (*types.Package, error) {
+// On success it sets lpkg.Types to a new Package.
+func (ld *loader) loadFromExportData(lpkg *loaderPackage) error {
 	if lpkg.PkgPath == "" {
 		log.Fatalf("internal error: Package %s has no PkgPath", lpkg)
 	}
@@ -1164,8 +1216,8 @@ func (ld *loader) loadFromExportData(lpkg *loaderPackage) (*types.Package, error
 	// must be sequential. (Finer-grained locking would require
 	// changes to the gcexportdata API.)
 	//
-	// The exportMu lock guards the Package.Pkg field and the
-	// types.Package it points to, for each Package in the graph.
+	// The exportMu lock guards the lpkg.Types field and the
+	// types.Package it points to, for each loaderPackage in the graph.
 	//
 	// Not all accesses to Package.Pkg need to be protected by exportMu:
 	// graph ordering ensures that direct dependencies of source
@@ -1174,18 +1226,18 @@ func (ld *loader) loadFromExportData(lpkg *loaderPackage) (*types.Package, error
 	defer ld.exportMu.Unlock()
 
 	if tpkg := lpkg.Types; tpkg != nil && tpkg.Complete() {
-		return tpkg, nil // cache hit
+		return nil // cache hit
 	}
 
 	lpkg.IllTyped = true // fail safe
 
 	if lpkg.ExportFile == "" {
 		// Errors while building export data will have been printed to stderr.
-		return nil, fmt.Errorf("no export data file")
+		return fmt.Errorf("no export data file")
 	}
 	f, err := os.Open(lpkg.ExportFile)
 	if err != nil {
-		return nil, err
+		return err
 	}
 	defer f.Close()
 
@@ -1197,7 +1249,7 @@ func (ld *loader) loadFromExportData(lpkg *loaderPackage) (*types.Package, error
 	// queries.)
 	r, err := gcexportdata.NewReader(f)
 	if err != nil {
-		return nil, fmt.Errorf("reading %s: %v", lpkg.ExportFile, err)
+		return fmt.Errorf("reading %s: %v", lpkg.ExportFile, err)
 	}
 
 	// Build the view.
@@ -1241,7 +1293,7 @@ func (ld *loader) loadFromExportData(lpkg *loaderPackage) (*types.Package, error
 	// (May modify incomplete packages in view but not create new ones.)
 	tpkg, err := gcexportdata.Read(r, ld.Fset, view, lpkg.PkgPath)
 	if err != nil {
-		return nil, fmt.Errorf("reading %s: %v", lpkg.ExportFile, err)
+		return fmt.Errorf("reading %s: %v", lpkg.ExportFile, err)
 	}
 	if _, ok := view["go.shape"]; ok {
 		// Account for the pseudopackage "go.shape" that gets
@@ -1254,8 +1306,7 @@ func (ld *loader) loadFromExportData(lpkg *loaderPackage) (*types.Package, error
 
 	lpkg.Types = tpkg
 	lpkg.IllTyped = false
-
-	return tpkg, nil
+	return nil
 }
 
 // impliedLoadMode returns loadMode with its dependencies.
@@ -1271,3 +1322,5 @@ func impliedLoadMode(loadMode LoadMode) LoadMode {
 func usesExportData(cfg *Config) bool {
 	return cfg.Mode&NeedExportFile != 0 || cfg.Mode&NeedTypes != 0 && cfg.Mode&NeedDeps == 0
 }
+
+var _ interface{} = io.Discard // assert build toolchain is go1.16 or later

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

@@ -12,7 +12,6 @@ import (
 	"bytes"
 	"encoding/binary"
 	"fmt"
-	"go/ast"
 	"go/constant"
 	"go/token"
 	"go/types"
@@ -145,7 +144,7 @@ func BExportData(fset *token.FileSet, pkg *types.Package) (b []byte, err error)
 	objcount := 0
 	scope := pkg.Scope()
 	for _, name := range scope.Names() {
-		if !ast.IsExported(name) {
+		if !token.IsExported(name) {
 			continue
 		}
 		if trace {
@@ -482,7 +481,7 @@ func (p *exporter) method(m *types.Func) {
 
 	p.pos(m)
 	p.string(m.Name())
-	if m.Name() != "_" && !ast.IsExported(m.Name()) {
+	if m.Name() != "_" && !token.IsExported(m.Name()) {
 		p.pkg(m.Pkg(), false)
 	}
 
@@ -501,7 +500,7 @@ func (p *exporter) fieldName(f *types.Var) {
 		// 3) field name doesn't match base type name (alias name)
 		bname := basetypeName(f.Type())
 		if name == bname {
-			if ast.IsExported(name) {
+			if token.IsExported(name) {
 				name = "" // 1) we don't need to know the field name or package
 			} else {
 				name = "?" // 2) use unexported name "?" to force package export
@@ -514,7 +513,7 @@ func (p *exporter) fieldName(f *types.Var) {
 	}
 
 	p.string(name)
-	if name != "" && !ast.IsExported(name) {
+	if name != "" && !token.IsExported(name) {
 		p.pkg(f.Pkg(), false)
 	}
 }

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

@@ -0,0 +1,265 @@
+// Copyright 2011 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.
+
+// This file is a reduced copy of $GOROOT/src/go/internal/gcimporter/gcimporter.go.
+
+// Package gcimporter provides various functions for reading
+// gc-generated object files that can be used to implement the
+// Importer interface defined by the Go 1.5 standard library package.
+package gcimporter // import "golang.org/x/tools/internal/gcimporter"
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"go/build"
+	"go/token"
+	"go/types"
+	"io"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"sync"
+)
+
+const (
+	// Enable debug during development: it adds some additional checks, and
+	// prevents errors from being recovered.
+	debug = false
+
+	// If trace is set, debugging output is printed to std out.
+	trace = false
+)
+
+var exportMap sync.Map // package dir → func() (string, bool)
+
+// lookupGorootExport returns the location of the export data
+// (normally found in the build cache, but located in GOROOT/pkg
+// in prior Go releases) for the package located in pkgDir.
+//
+// (We use the package's directory instead of its import path
+// mainly to simplify handling of the packages in src/vendor
+// and cmd/vendor.)
+func lookupGorootExport(pkgDir string) (string, bool) {
+	f, ok := exportMap.Load(pkgDir)
+	if !ok {
+		var (
+			listOnce   sync.Once
+			exportPath string
+		)
+		f, _ = exportMap.LoadOrStore(pkgDir, func() (string, bool) {
+			listOnce.Do(func() {
+				cmd := exec.Command("go", "list", "-export", "-f", "{{.Export}}", pkgDir)
+				cmd.Dir = build.Default.GOROOT
+				var output []byte
+				output, err := cmd.Output()
+				if err != nil {
+					return
+				}
+
+				exports := strings.Split(string(bytes.TrimSpace(output)), "\n")
+				if len(exports) != 1 {
+					return
+				}
+
+				exportPath = exports[0]
+			})
+
+			return exportPath, exportPath != ""
+		})
+	}
+
+	return f.(func() (string, bool))()
+}
+
+var pkgExts = [...]string{".a", ".o"}
+
+// FindPkg returns the filename and unique package id for an import
+// path based on package information provided by build.Import (using
+// 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
+	}
+
+	var noext string
+	switch {
+	default:
+		// "x" -> "$GOPATH/pkg/$GOOS_$GOARCH/x.ext", "x"
+		// Don't require the source files to be present.
+		if abs, err := filepath.Abs(srcDir); err == nil { // see issue 14282
+			srcDir = abs
+		}
+		bp, _ := build.Import(path, srcDir, build.FindOnly|build.AllowBinary)
+		if bp.PkgObj == "" {
+			var ok bool
+			if bp.Goroot && bp.Dir != "" {
+				filename, ok = lookupGorootExport(bp.Dir)
+			}
+			if !ok {
+				id = path // make sure we have an id to print in error message
+				return
+			}
+		} else {
+			noext = strings.TrimSuffix(bp.PkgObj, ".a")
+			id = bp.ImportPath
+		}
+
+	case build.IsLocalImport(path):
+		// "./x" -> "/this/directory/x.ext", "/this/directory/x"
+		noext = filepath.Join(srcDir, path)
+		id = noext
+
+	case filepath.IsAbs(path):
+		// for completeness only - go/build.Import
+		// does not support absolute imports
+		// "/x" -> "/x.ext", "/x"
+		noext = path
+		id = path
+	}
+
+	if false { // for debugging
+		if path != id {
+			fmt.Printf("%s -> %s\n", path, id)
+		}
+	}
+
+	if filename != "" {
+		if f, err := os.Stat(filename); err == nil && !f.IsDir() {
+			return
+		}
+	}
+
+	// try extensions
+	for _, ext := range pkgExts {
+		filename = noext + ext
+		if f, err := os.Stat(filename); err == nil && !f.IsDir() {
+			return
+		}
+	}
+
+	filename = "" // not found
+	return
+}
+
+// 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
+	if lookup != nil {
+		// With custom lookup specified, assume that caller has
+		// converted path to a canonical import path for use in the map.
+		if path == "unsafe" {
+			return types.Unsafe, nil
+		}
+		id = path
+
+		// No need to re-import if the package was imported completely before.
+		if pkg = packages[id]; pkg != nil && pkg.Complete() {
+			return
+		}
+		f, err := lookup(path)
+		if err != nil {
+			return nil, err
+		}
+		rc = f
+	} else {
+		filename, id = FindPkg(path, srcDir)
+		if filename == "" {
+			if path == "unsafe" {
+				return types.Unsafe, nil
+			}
+			return nil, fmt.Errorf("can't find import: %q", id)
+		}
+
+		// no need to re-import if the package was imported completely before
+		if pkg = packages[id]; pkg != nil && pkg.Complete() {
+			return
+		}
+
+		// open file
+		f, err := os.Open(filename)
+		if err != nil {
+			return nil, err
+		}
+		defer func() {
+			if err != nil {
+				// add file name to error
+				err = fmt.Errorf("%s: %v", filename, err)
+			}
+		}()
+		rc = f
+	}
+	defer rc.Close()
+
+	var hdr string
+	var size int64
+	buf := bufio.NewReader(rc)
+	if hdr, size, err = FindExportData(buf); err != nil {
+		return
+	}
+
+	switch hdr {
+	case "$$B\n":
+		var data []byte
+		data, err = ioutil.ReadAll(buf)
+		if err != nil {
+			break
+		}
+
+		// TODO(gri): allow clients of go/importer to provide a FileSet.
+		// Or, define a new standard go/types/gcexportdata package.
+		fset := token.NewFileSet()
+
+		// 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 {
+			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:
+		err = fmt.Errorf("unknown export data header: %q", hdr)
+	}
+
+	return
+}
+
+func deref(typ types.Type) types.Type {
+	if p, _ := typ.(*types.Pointer); p != nil {
+		return p.Elem()
+	}
+	return typ
+}
+
+type byPath []*types.Package
+
+func (a byPath) Len() int           { return len(a) }
+func (a byPath) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
+func (a byPath) Less(i, j int) bool { return a[i].Path() < a[j].Path() }

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

@@ -12,7 +12,6 @@ import (
 	"bytes"
 	"encoding/binary"
 	"fmt"
-	"go/ast"
 	"go/constant"
 	"go/token"
 	"go/types"
@@ -23,9 +22,45 @@ import (
 	"strconv"
 	"strings"
 
+	"golang.org/x/tools/internal/tokeninternal"
 	"golang.org/x/tools/internal/typeparams"
 )
 
+// IExportShallow encodes "shallow" export data for the specified package.
+//
+// No promises are made about the encoding other than that it can be
+// decoded by the same version of IIExportShallow. If you plan to save
+// export data in the file system, be sure to include a cryptographic
+// digest of the executable in the key to avoid version skew.
+func IExportShallow(fset *token.FileSet, pkg *types.Package) ([]byte, error) {
+	// In principle this operation can only fail if out.Write fails,
+	// but that's impossible for bytes.Buffer---and as a matter of
+	// fact iexportCommon doesn't even check for I/O errors.
+	// TODO(adonovan): handle I/O errors properly.
+	// TODO(adonovan): use byte slices throughout, avoiding copying.
+	const bundle, shallow = false, true
+	var out bytes.Buffer
+	err := iexportCommon(&out, fset, bundle, shallow, iexportVersion, []*types.Package{pkg})
+	return out.Bytes(), err
+}
+
+// IImportShallow decodes "shallow" types.Package data encoded by IExportShallow
+// in the same executable. This function cannot import data from
+// cmd/compile or gcexportdata.Write.
+func IImportShallow(fset *token.FileSet, imports map[string]*types.Package, data []byte, path string, insert InsertType) (*types.Package, error) {
+	const bundle = false
+	pkgs, err := iimportCommon(fset, imports, data, bundle, path, insert)
+	if err != nil {
+		return nil, err
+	}
+	return pkgs[0], nil
+}
+
+// InsertType is the type of a function that creates a types.TypeName
+// object for a named type and inserts it into the scope of the
+// specified Package.
+type InsertType = func(pkg *types.Package, name string)
+
 // Current bundled export format version. Increase with each format change.
 // 0: initial implementation
 const bundleVersion = 0
@@ -36,15 +71,17 @@ const bundleVersion = 0
 // The package path of the top-level package will not be recorded,
 // so that calls to IImportData can override with a provided package path.
 func IExportData(out io.Writer, fset *token.FileSet, pkg *types.Package) error {
-	return iexportCommon(out, fset, false, iexportVersion, []*types.Package{pkg})
+	const bundle, shallow = false, false
+	return iexportCommon(out, fset, bundle, shallow, iexportVersion, []*types.Package{pkg})
 }
 
 // IExportBundle writes an indexed export bundle for pkgs to out.
 func IExportBundle(out io.Writer, fset *token.FileSet, pkgs []*types.Package) error {
-	return iexportCommon(out, fset, true, iexportVersion, pkgs)
+	const bundle, shallow = true, false
+	return iexportCommon(out, fset, bundle, shallow, iexportVersion, pkgs)
 }
 
-func iexportCommon(out io.Writer, fset *token.FileSet, bundle bool, version int, pkgs []*types.Package) (err error) {
+func iexportCommon(out io.Writer, fset *token.FileSet, bundle, shallow bool, version int, pkgs []*types.Package) (err error) {
 	if !debug {
 		defer func() {
 			if e := recover(); e != nil {
@@ -61,6 +98,7 @@ func iexportCommon(out io.Writer, fset *token.FileSet, bundle bool, version int,
 	p := iexporter{
 		fset:        fset,
 		version:     version,
+		shallow:     shallow,
 		allPkgs:     map[*types.Package]bool{},
 		stringIndex: map[string]uint64{},
 		declIndex:   map[types.Object]uint64{},
@@ -82,7 +120,7 @@ func iexportCommon(out io.Writer, fset *token.FileSet, bundle bool, version int,
 	for _, pkg := range pkgs {
 		scope := pkg.Scope()
 		for _, name := range scope.Names() {
-			if ast.IsExported(name) {
+			if token.IsExported(name) {
 				p.pushDecl(scope.Lookup(name))
 			}
 		}
@@ -101,6 +139,17 @@ func iexportCommon(out io.Writer, fset *token.FileSet, bundle bool, version int,
 		p.doDecl(p.declTodo.popHead())
 	}
 
+	// Produce index of offset of each file record in files.
+	var files intWriter
+	var fileOffset []uint64 // fileOffset[i] is offset in files of file encoded as i
+	if p.shallow {
+		fileOffset = make([]uint64, len(p.fileInfos))
+		for i, info := range p.fileInfos {
+			fileOffset[i] = uint64(files.Len())
+			p.encodeFile(&files, info.file, info.needed)
+		}
+	}
+
 	// Append indices to data0 section.
 	dataLen := uint64(p.data0.Len())
 	w := p.newWriter()
@@ -126,16 +175,75 @@ func iexportCommon(out io.Writer, fset *token.FileSet, bundle bool, version int,
 	}
 	hdr.uint64(uint64(p.version))
 	hdr.uint64(uint64(p.strings.Len()))
+	if p.shallow {
+		hdr.uint64(uint64(files.Len()))
+		hdr.uint64(uint64(len(fileOffset)))
+		for _, offset := range fileOffset {
+			hdr.uint64(offset)
+		}
+	}
 	hdr.uint64(dataLen)
 
 	// Flush output.
 	io.Copy(out, &hdr)
 	io.Copy(out, &p.strings)
+	if p.shallow {
+		io.Copy(out, &files)
+	}
 	io.Copy(out, &p.data0)
 
 	return nil
 }
 
+// encodeFile writes to w a representation of the file sufficient to
+// faithfully restore position information about all needed offsets.
+// Mutates the needed array.
+func (p *iexporter) encodeFile(w *intWriter, file *token.File, needed []uint64) {
+	_ = needed[0] // precondition: needed is non-empty
+
+	w.uint64(p.stringOff(file.Name()))
+
+	size := uint64(file.Size())
+	w.uint64(size)
+
+	// Sort the set of needed offsets. Duplicates are harmless.
+	sort.Slice(needed, func(i, j int) bool { return needed[i] < needed[j] })
+
+	lines := tokeninternal.GetLines(file) // byte offset of each line start
+	w.uint64(uint64(len(lines)))
+
+	// Rather than record the entire array of line start offsets,
+	// we save only a sparse list of (index, offset) pairs for
+	// the start of each line that contains a needed position.
+	var sparse [][2]int // (index, offset) pairs
+outer:
+	for i, lineStart := range lines {
+		lineEnd := size
+		if i < len(lines)-1 {
+			lineEnd = uint64(lines[i+1])
+		}
+		// Does this line contains a needed offset?
+		if needed[0] < lineEnd {
+			sparse = append(sparse, [2]int{i, lineStart})
+			for needed[0] < lineEnd {
+				needed = needed[1:]
+				if len(needed) == 0 {
+					break outer
+				}
+			}
+		}
+	}
+
+	// Delta-encode the columns.
+	w.uint64(uint64(len(sparse)))
+	var prev [2]int
+	for _, pair := range sparse {
+		w.uint64(uint64(pair[0] - prev[0]))
+		w.uint64(uint64(pair[1] - prev[1]))
+		prev = pair
+	}
+}
+
 // writeIndex writes out an object index. mainIndex indicates whether
 // we're writing out the main index, which is also read by
 // non-compiler tools and includes a complete package description
@@ -205,7 +313,8 @@ type iexporter struct {
 	out     *bytes.Buffer
 	version int
 
-	localpkg *types.Package
+	shallow  bool           // don't put types from other packages in the index
+	localpkg *types.Package // (nil in bundle mode)
 
 	// allPkgs tracks all packages that have been referenced by
 	// the export data, so we can ensure to include them in the
@@ -217,6 +326,12 @@ type iexporter struct {
 	strings     intWriter
 	stringIndex map[string]uint64
 
+	// In shallow mode, object positions are encoded as (file, offset).
+	// Each file is recorded as a line-number table.
+	// Only the lines of needed positions are saved faithfully.
+	fileInfo  map[*token.File]uint64 // value is index in fileInfos
+	fileInfos []*filePositions
+
 	data0       intWriter
 	declIndex   map[types.Object]uint64
 	tparamNames map[types.Object]string // typeparam->exported name
@@ -225,6 +340,11 @@ type iexporter struct {
 	indent int // for tracing support
 }
 
+type filePositions struct {
+	file   *token.File
+	needed []uint64 // unordered list of needed file offsets
+}
+
 func (p *iexporter) trace(format string, args ...interface{}) {
 	if !trace {
 		// Call sites should also be guarded, but having this check here allows
@@ -248,6 +368,25 @@ func (p *iexporter) stringOff(s string) uint64 {
 	return off
 }
 
+// fileIndexAndOffset returns the index of the token.File and the byte offset of pos within it.
+func (p *iexporter) fileIndexAndOffset(file *token.File, pos token.Pos) (uint64, uint64) {
+	index, ok := p.fileInfo[file]
+	if !ok {
+		index = uint64(len(p.fileInfo))
+		p.fileInfos = append(p.fileInfos, &filePositions{file: file})
+		if p.fileInfo == nil {
+			p.fileInfo = make(map[*token.File]uint64)
+		}
+		p.fileInfo[file] = index
+	}
+	// Record each needed offset.
+	info := p.fileInfos[index]
+	offset := uint64(file.Offset(pos))
+	info.needed = append(info.needed, offset)
+
+	return index, offset
+}
+
 // 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.
@@ -256,6 +395,11 @@ func (p *iexporter) pushDecl(obj types.Object) {
 		panic("cannot export package unsafe")
 	}
 
+	// Shallow export data: don't index decls from other packages.
+	if p.shallow && obj.Pkg() != p.localpkg {
+		return
+	}
+
 	if _, ok := p.declIndex[obj]; ok {
 		return
 	}
@@ -303,7 +447,13 @@ func (p *iexporter) doDecl(obj types.Object) {
 	case *types.Func:
 		sig, _ := obj.Type().(*types.Signature)
 		if sig.Recv() != nil {
-			panic(internalErrorf("unexpected method: %v", sig))
+			// We shouldn't see methods in the package scope,
+			// but the type checker may repair "func () F() {}"
+			// to "func (Invalid) F()" and then treat it like "func F()",
+			// so allow that. See golang/go#57729.
+			if sig.Recv().Type() != types.Typ[types.Invalid] {
+				panic(internalErrorf("unexpected method: %v", sig))
+			}
 		}
 
 		// Function.
@@ -415,13 +565,30 @@ func (w *exportWriter) tag(tag byte) {
 }
 
 func (w *exportWriter) pos(pos token.Pos) {
-	if w.p.version >= iexportVersionPosCol {
+	if w.p.shallow {
+		w.posV2(pos)
+	} else if w.p.version >= iexportVersionPosCol {
 		w.posV1(pos)
 	} else {
 		w.posV0(pos)
 	}
 }
 
+// posV2 encoding (used only in shallow mode) records positions as
+// (file, offset), where file is the index in the token.File table
+// (which records the file name and newline offsets) and offset is a
+// byte offset. It effectively ignores //line directives.
+func (w *exportWriter) posV2(pos token.Pos) {
+	if pos == token.NoPos {
+		w.uint64(0)
+		return
+	}
+	file := w.p.fset.File(pos) // fset must be non-nil
+	index, offset := w.p.fileIndexAndOffset(file, pos)
+	w.uint64(1 + index)
+	w.uint64(offset)
+}
+
 func (w *exportWriter) posV1(pos token.Pos) {
 	if w.p.fset == nil {
 		w.int64(0)
@@ -497,7 +664,7 @@ func (w *exportWriter) pkg(pkg *types.Package) {
 	w.string(w.exportPath(pkg))
 }
 
-func (w *exportWriter) qualifiedIdent(obj types.Object) {
+func (w *exportWriter) qualifiedType(obj *types.TypeName) {
 	name := w.p.exportName(obj)
 
 	// Ensure any referenced declarations are written out too.
@@ -556,11 +723,11 @@ func (w *exportWriter) doTyp(t types.Type, pkg *types.Package) {
 			return
 		}
 		w.startType(definedType)
-		w.qualifiedIdent(t.Obj())
+		w.qualifiedType(t.Obj())
 
 	case *typeparams.TypeParam:
 		w.startType(typeParamType)
-		w.qualifiedIdent(t.Obj())
+		w.qualifiedType(t.Obj())
 
 	case *types.Pointer:
 		w.startType(pointerType)
@@ -602,14 +769,17 @@ func (w *exportWriter) doTyp(t types.Type, pkg *types.Package) {
 
 	case *types.Struct:
 		w.startType(structType)
-		w.setPkg(pkg, true)
-
 		n := t.NumFields()
+		if n > 0 {
+			w.setPkg(t.Field(0).Pkg(), true) // qualifying package for field objects
+		} else {
+			w.setPkg(pkg, true)
+		}
 		w.uint64(uint64(n))
 		for i := 0; i < n; i++ {
 			f := t.Field(i)
 			w.pos(f.Pos())
-			w.string(f.Name())
+			w.string(f.Name()) // unexported fields implicitly qualified by prior setPkg
 			w.typ(f.Type(), pkg)
 			w.bool(f.Anonymous())
 			w.string(t.Tag(i)) // note (or tag)

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

@@ -51,6 +51,8 @@ const (
 	iexportVersionPosCol   = 1
 	iexportVersionGo1_18   = 2
 	iexportVersionGenerics = 2
+
+	iexportVersionCurrent = 2
 )
 
 type ident struct {
@@ -83,7 +85,7 @@ const (
 // If the export data version is not recognized or the format is otherwise
 // compromised, an error is returned.
 func IImportData(fset *token.FileSet, imports map[string]*types.Package, data []byte, path string) (int, *types.Package, error) {
-	pkgs, err := iimportCommon(fset, imports, data, false, path)
+	pkgs, err := iimportCommon(fset, imports, data, false, path, nil)
 	if err != nil {
 		return 0, nil, err
 	}
@@ -92,11 +94,11 @@ func IImportData(fset *token.FileSet, imports map[string]*types.Package, data []
 
 // IImportBundle imports a set of packages from the serialized package bundle.
 func IImportBundle(fset *token.FileSet, imports map[string]*types.Package, data []byte) ([]*types.Package, error) {
-	return iimportCommon(fset, imports, data, true, "")
+	return iimportCommon(fset, imports, data, true, "", nil)
 }
 
-func iimportCommon(fset *token.FileSet, imports map[string]*types.Package, data []byte, bundle bool, path string) (pkgs []*types.Package, err error) {
-	const currentVersion = 1
+func iimportCommon(fset *token.FileSet, imports map[string]*types.Package, data []byte, bundle bool, path string, insert InsertType) (pkgs []*types.Package, err error) {
+	const currentVersion = iexportVersionCurrent
 	version := int64(-1)
 	if !debug {
 		defer func() {
@@ -135,19 +137,34 @@ func iimportCommon(fset *token.FileSet, imports map[string]*types.Package, data
 	}
 
 	sLen := int64(r.uint64())
+	var fLen int64
+	var fileOffset []uint64
+	if insert != nil {
+		// Shallow mode uses a different position encoding.
+		fLen = int64(r.uint64())
+		fileOffset = make([]uint64, r.uint64())
+		for i := range fileOffset {
+			fileOffset[i] = r.uint64()
+		}
+	}
 	dLen := int64(r.uint64())
 
 	whence, _ := r.Seek(0, io.SeekCurrent)
 	stringData := data[whence : whence+sLen]
-	declData := data[whence+sLen : whence+sLen+dLen]
-	r.Seek(sLen+dLen, io.SeekCurrent)
+	fileData := data[whence+sLen : whence+sLen+fLen]
+	declData := data[whence+sLen+fLen : whence+sLen+fLen+dLen]
+	r.Seek(sLen+fLen+dLen, io.SeekCurrent)
 
 	p := iimporter{
 		version: int(version),
 		ipath:   path,
+		insert:  insert,
 
 		stringData:  stringData,
 		stringCache: make(map[uint64]string),
+		fileOffset:  fileOffset,
+		fileData:    fileData,
+		fileCache:   make([]*token.File, len(fileOffset)),
 		pkgCache:    make(map[uint64]*types.Package),
 
 		declData: declData,
@@ -185,11 +202,18 @@ func iimportCommon(fset *token.FileSet, imports map[string]*types.Package, data
 		} else if pkg.Name() != pkgName {
 			errorf("conflicting names %s and %s for package %q", pkg.Name(), pkgName, path)
 		}
+		if i == 0 && !bundle {
+			p.localpkg = pkg
+		}
 
 		p.pkgCache[pkgPathOff] = pkg
 
+		// Read index for package.
 		nameIndex := make(map[string]uint64)
-		for nSyms := r.uint64(); nSyms > 0; nSyms-- {
+		nSyms := r.uint64()
+		// In shallow mode we don't expect an index for other packages.
+		assert(nSyms == 0 || p.localpkg == pkg || p.insert == nil)
+		for ; nSyms > 0; nSyms-- {
 			name := p.stringAt(r.uint64())
 			nameIndex[name] = r.uint64()
 		}
@@ -265,8 +289,14 @@ type iimporter struct {
 	version int
 	ipath   string
 
+	localpkg *types.Package
+	insert   func(pkg *types.Package, name string) // "shallow" mode only
+
 	stringData  []byte
 	stringCache map[uint64]string
+	fileOffset  []uint64 // fileOffset[i] is offset in fileData for info about file encoded as i
+	fileData    []byte
+	fileCache   []*token.File // memoized decoding of file encoded as i
 	pkgCache    map[uint64]*types.Package
 
 	declData    []byte
@@ -308,6 +338,13 @@ func (p *iimporter) doDecl(pkg *types.Package, name string) {
 
 	off, ok := p.pkgIndex[pkg][name]
 	if !ok {
+		// In "shallow" mode, call back to the application to
+		// find the object and insert it into the package scope.
+		if p.insert != nil {
+			assert(pkg != p.localpkg)
+			p.insert(pkg, name) // "can't fail"
+			return
+		}
 		errorf("%v.%v not in index", pkg, name)
 	}
 
@@ -332,6 +369,55 @@ func (p *iimporter) stringAt(off uint64) string {
 	return s
 }
 
+func (p *iimporter) fileAt(index uint64) *token.File {
+	file := p.fileCache[index]
+	if file == nil {
+		off := p.fileOffset[index]
+		file = p.decodeFile(intReader{bytes.NewReader(p.fileData[off:]), p.ipath})
+		p.fileCache[index] = file
+	}
+	return file
+}
+
+func (p *iimporter) decodeFile(rd intReader) *token.File {
+	filename := p.stringAt(rd.uint64())
+	size := int(rd.uint64())
+	file := p.fake.fset.AddFile(filename, -1, size)
+
+	// SetLines requires a nondecreasing sequence.
+	// Because it is common for clients to derive the interval
+	// [start, start+len(name)] from a start position, and we
+	// want to ensure that the end offset is on the same line,
+	// we fill in the gaps of the sparse encoding with values
+	// that strictly increase by the largest possible amount.
+	// This allows us to avoid having to record the actual end
+	// offset of each needed line.
+
+	lines := make([]int, int(rd.uint64()))
+	var index, offset int
+	for i, n := 0, int(rd.uint64()); i < n; i++ {
+		index += int(rd.uint64())
+		offset += int(rd.uint64())
+		lines[index] = offset
+
+		// Ensure monotonicity between points.
+		for j := index - 1; j > 0 && lines[j] == 0; j-- {
+			lines[j] = lines[j+1] - 1
+		}
+	}
+
+	// Ensure monotonicity after last point.
+	for j := len(lines) - 1; j > 0 && lines[j] == 0; j-- {
+		size--
+		lines[j] = size
+	}
+
+	if !file.SetLines(lines) {
+		errorf("SetLines failed: %d", lines) // can't happen
+	}
+	return file
+}
+
 func (p *iimporter) pkgAt(off uint64) *types.Package {
 	if pkg, ok := p.pkgCache[off]; ok {
 		return pkg
@@ -625,6 +711,9 @@ func (r *importReader) qualifiedIdent() (*types.Package, string) {
 }
 
 func (r *importReader) pos() token.Pos {
+	if r.p.insert != nil { // shallow mode
+		return r.posv2()
+	}
 	if r.p.version >= iexportVersionPosCol {
 		r.posv1()
 	} else {
@@ -661,6 +750,15 @@ func (r *importReader) posv1() {
 	}
 }
 
+func (r *importReader) posv2() token.Pos {
+	file := r.uint64()
+	if file == 0 {
+		return token.NoPos
+	}
+	tf := r.p.fileAt(file - 1)
+	return tf.Pos(int(r.uint64()))
+}
+
 func (r *importReader) typ() types.Type {
 	return r.p.typAt(r.uint64(), nil)
 }

vendor/golang.org/x/tools/internal/gcimporter/support_go118.go

@@ -21,3 +21,17 @@ func additionalPredeclared() []types.Type {
 		types.Universe.Lookup("any").Type(),
 	}
 }
+
+// See cmd/compile/internal/types.SplitVargenSuffix.
+func splitVargenSuffix(name string) (base, suffix string) {
+	i := len(name)
+	for i > 0 && name[i-1] >= '0' && name[i-1] <= '9' {
+		i--
+	}
+	const dot = "·"
+	if i >= len(dot) && name[i-len(dot):i] == dot {
+		i -= len(dot)
+		return name[:i], name[i:]
+	}
+	return name, ""
+}

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

@@ -14,7 +14,7 @@ import (
 	"go/types"
 	"strings"
 
-	"golang.org/x/tools/go/internal/pkgbits"
+	"golang.org/x/tools/internal/pkgbits"
 )
 
 // A pkgReader holds the shared state for reading a unified IR package
@@ -36,6 +36,12 @@ type pkgReader struct {
 	// laterFns holds functions that need to be invoked at the end of
 	// import reading.
 	laterFns []func()
+	// laterFors is used in case of 'type A B' to ensure that B is processed before A.
+	laterFors map[types.Type]int
+
+	// ifaces holds a list of constructed Interfaces, which need to have
+	// Complete called after importing is done.
+	ifaces []*types.Interface
 }
 
 // later adds a function to be invoked at the end of import reading.
@@ -63,6 +69,15 @@ func UImportData(fset *token.FileSet, imports map[string]*types.Package, data []
 	return
 }
 
+// laterFor adds a function to be invoked at the end of import reading, and records the type that function is finishing.
+func (pr *pkgReader) laterFor(t types.Type, fn func()) {
+	if pr.laterFors == nil {
+		pr.laterFors = make(map[types.Type]int)
+	}
+	pr.laterFors[t] = len(pr.laterFns)
+	pr.laterFns = append(pr.laterFns, fn)
+}
+
 // 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 {
@@ -102,6 +117,10 @@ func readUnifiedPackage(fset *token.FileSet, ctxt *types.Context, imports map[st
 		fn()
 	}
 
+	for _, iface := range pr.ifaces {
+		iface.Complete()
+	}
+
 	pkg.MarkComplete()
 	return pkg
 }
@@ -139,6 +158,17 @@ func (pr *pkgReader) newReader(k pkgbits.RelocKind, idx pkgbits.Index, marker pk
 	}
 }
 
+func (pr *pkgReader) tempReader(k pkgbits.RelocKind, idx pkgbits.Index, marker pkgbits.SyncMarker) *reader {
+	return &reader{
+		Decoder: pr.TempDecoder(k, idx, marker),
+		p:       pr,
+	}
+}
+
+func (pr *pkgReader) retireReader(r *reader) {
+	pr.RetireDecoder(&r.Decoder)
+}
+
 // @@@ Positions
 
 func (r *reader) pos() token.Pos {
@@ -163,26 +193,29 @@ func (pr *pkgReader) posBaseIdx(idx pkgbits.Index) string {
 		return b
 	}
 
-	r := pr.newReader(pkgbits.RelocPosBase, idx, pkgbits.SyncPosBase)
+	var filename string
+	{
+		r := pr.tempReader(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.
+		// 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()
+		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()
+		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
+			// Was: "b = token.NewLineBase(pos, filename, true, line, col)"
+			_, _, _ = pos, line, col
+		}
+		pr.retireReader(r)
 	}
-
 	b := filename
 	pr.posBases[idx] = b
 	return b
@@ -231,11 +264,35 @@ func (r *reader) doPkg() *types.Package {
 	for i := range imports {
 		imports[i] = r.pkg()
 	}
-	pkg.SetImports(imports)
+	pkg.SetImports(flattenImports(imports))
 
 	return pkg
 }
 
+// flattenImports returns the transitive closure of all imported
+// packages rooted from pkgs.
+func flattenImports(pkgs []*types.Package) []*types.Package {
+	var res []*types.Package
+	seen := make(map[*types.Package]struct{})
+	for _, pkg := range pkgs {
+		if _, ok := seen[pkg]; ok {
+			continue
+		}
+		seen[pkg] = struct{}{}
+		res = append(res, pkg)
+
+		// pkg.Imports() is already flattened.
+		for _, pkg := range pkg.Imports() {
+			if _, ok := seen[pkg]; ok {
+				continue
+			}
+			seen[pkg] = struct{}{}
+			res = append(res, pkg)
+		}
+	}
+	return res
+}
+
 // @@@ Types
 
 func (r *reader) typ() types.Type {
@@ -264,12 +321,15 @@ func (pr *pkgReader) typIdx(info typeInfo, dict *readerDict) types.Type {
 		return typ
 	}
 
-	r := pr.newReader(pkgbits.RelocType, idx, pkgbits.SyncTypeIdx)
-	r.dict = dict
-
-	typ := r.doTyp()
-	assert(typ != nil)
+	var typ types.Type
+	{
+		r := pr.tempReader(pkgbits.RelocType, idx, pkgbits.SyncTypeIdx)
+		r.dict = dict
 
+		typ = r.doTyp()
+		assert(typ != nil)
+		pr.retireReader(r)
+	}
 	// See comment in pkgReader.typIdx explaining how this happens.
 	if prev := *where; prev != nil {
 		return prev
@@ -372,6 +432,16 @@ func (r *reader) interfaceType() *types.Interface {
 	if implicit {
 		iface.MarkImplicit()
 	}
+
+	// We need to call iface.Complete(), but if there are any embedded
+	// defined types, then we may not have set their underlying
+	// interface type yet. So we need to defer calling Complete until
+	// after we've called SetUnderlying everywhere.
+	//
+	// TODO(mdempsky): After CL 424876 lands, it should be safe to call
+	// iface.Complete() immediately.
+	r.p.ifaces = append(r.p.ifaces, iface)
+
 	return iface
 }
 
@@ -425,18 +495,30 @@ func (r *reader) obj() (types.Object, []types.Type) {
 }
 
 func (pr *pkgReader) objIdx(idx pkgbits.Index) (*types.Package, string) {
-	rname := pr.newReader(pkgbits.RelocName, idx, pkgbits.SyncObject1)
 
-	objPkg, objName := rname.qualifiedIdent()
-	assert(objName != "")
+	var objPkg *types.Package
+	var objName string
+	var tag pkgbits.CodeObj
+	{
+		rname := pr.tempReader(pkgbits.RelocName, idx, pkgbits.SyncObject1)
 
-	tag := pkgbits.CodeObj(rname.Code(pkgbits.SyncCodeObj))
+		objPkg, objName = rname.qualifiedIdent()
+		assert(objName != "")
+
+		tag = pkgbits.CodeObj(rname.Code(pkgbits.SyncCodeObj))
+		pr.retireReader(rname)
+	}
 
 	if tag == pkgbits.ObjStub {
 		assert(objPkg == nil || objPkg == types.Unsafe)
 		return objPkg, objName
 	}
 
+	// Ignore local types promoted to global scope (#55110).
+	if _, suffix := splitVargenSuffix(objName); suffix != "" {
+		return objPkg, objName
+	}
+
 	if objPkg.Scope().Lookup(objName) == nil {
 		dict := pr.objDictIdx(idx)
 
@@ -477,15 +559,56 @@ func (pr *pkgReader) objIdx(idx pkgbits.Index) (*types.Package, string) {
 
 			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()
+			setUnderlying := func(underlying types.Type) {
+				// If the underlying type is an interface, we need to
+				// duplicate its methods so we can replace the receiver
+				// parameter's type (#49906).
+				if iface, ok := underlying.(*types.Interface); ok && iface.NumExplicitMethods() != 0 {
+					methods := make([]*types.Func, iface.NumExplicitMethods())
+					for i := range methods {
+						fn := iface.ExplicitMethod(i)
+						sig := fn.Type().(*types.Signature)
+
+						recv := types.NewVar(fn.Pos(), fn.Pkg(), "", named)
+						methods[i] = types.NewFunc(fn.Pos(), fn.Pkg(), fn.Name(), types.NewSignature(recv, sig.Params(), sig.Results(), sig.Variadic()))
+					}
+
+					embeds := make([]types.Type, iface.NumEmbeddeds())
+					for i := range embeds {
+						embeds[i] = iface.EmbeddedType(i)
+					}
+
+					newIface := types.NewInterfaceType(methods, embeds)
+					r.p.ifaces = append(r.p.ifaces, newIface)
+					underlying = newIface
+				}
+
 				named.SetUnderlying(underlying)
-			})
+			}
+
+			// Since go.dev/cl/455279, we can assume rhs.Underlying() will
+			// always be non-nil. However, to temporarily support users of
+			// older snapshot releases, we continue to fallback to the old
+			// behavior for now.
+			//
+			// TODO(mdempsky): Remove fallback code and simplify after
+			// allowing time for snapshot users to upgrade.
+			rhs := r.typ()
+			if underlying := rhs.Underlying(); underlying != nil {
+				setUnderlying(underlying)
+			} else {
+				pk := r.p
+				pk.laterFor(named, func() {
+					// First be sure that the rhs is initialized, if it needs to be initialized.
+					delete(pk.laterFors, named) // prevent cycles
+					if i, ok := pk.laterFors[rhs]; ok {
+						f := pk.laterFns[i]
+						pk.laterFns[i] = func() {} // function is running now, so replace it with a no-op
+						f()                        // initialize RHS
+					}
+					setUnderlying(rhs.Underlying())
+				})
+			}
 
 			for i, n := 0, r.Len(); i < n; i++ {
 				named.AddMethod(r.method())
@@ -502,25 +625,28 @@ func (pr *pkgReader) objIdx(idx pkgbits.Index) (*types.Package, string) {
 }
 
 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)
-	}
+	{
+		r := pr.tempReader(pkgbits.RelocObjDict, idx, pkgbits.SyncObject1)
+		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.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()}
-	}
+		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()}
+		}
 
+		pr.retireReader(r)
+	}
 	// function references follow, but reader doesn't need those
 
 	return &dict

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

@@ -10,8 +10,10 @@ import (
 	"context"
 	"fmt"
 	"io"
+	"log"
 	"os"
 	"regexp"
+	"runtime"
 	"strconv"
 	"strings"
 	"sync"
@@ -232,6 +234,12 @@ func (i *Invocation) run(ctx context.Context, stdout, stderr io.Writer) error {
 	return runCmdContext(ctx, cmd)
 }
 
+// DebugHangingGoCommands may be set by tests to enable additional
+// instrumentation (including panics) for debugging hanging Go commands.
+//
+// See golang/go#54461 for details.
+var DebugHangingGoCommands = false
+
 // runCmdContext is like exec.CommandContext except it sends os.Interrupt
 // before os.Kill.
 func runCmdContext(ctx context.Context, cmd *exec.Cmd) error {
@@ -243,11 +251,24 @@ func runCmdContext(ctx context.Context, cmd *exec.Cmd) error {
 		resChan <- cmd.Wait()
 	}()
 
-	select {
-	case err := <-resChan:
-		return err
-	case <-ctx.Done():
+	// If we're interested in debugging hanging Go commands, stop waiting after a
+	// minute and panic with interesting information.
+	if DebugHangingGoCommands {
+		select {
+		case err := <-resChan:
+			return err
+		case <-time.After(1 * time.Minute):
+			HandleHangingGoCommand(cmd.Process)
+		case <-ctx.Done():
+		}
+	} else {
+		select {
+		case err := <-resChan:
+			return err
+		case <-ctx.Done():
+		}
 	}
+
 	// Cancelled. Interrupt and see if it ends voluntarily.
 	cmd.Process.Signal(os.Interrupt)
 	select {
@@ -255,11 +276,63 @@ func runCmdContext(ctx context.Context, cmd *exec.Cmd) error {
 		return err
 	case <-time.After(time.Second):
 	}
+
 	// Didn't shut down in response to interrupt. Kill it hard.
-	cmd.Process.Kill()
+	// TODO(rfindley): per advice from bcmills@, it may be better to send SIGQUIT
+	// on certain platforms, such as unix.
+	if err := cmd.Process.Kill(); err != nil && DebugHangingGoCommands {
+		// Don't panic here as this reliably fails on windows with EINVAL.
+		log.Printf("error killing the Go command: %v", err)
+	}
+
+	// See above: don't wait indefinitely if we're debugging hanging Go commands.
+	if DebugHangingGoCommands {
+		select {
+		case err := <-resChan:
+			return err
+		case <-time.After(10 * time.Second): // a shorter wait as resChan should return quickly following Kill
+			HandleHangingGoCommand(cmd.Process)
+		}
+	}
 	return <-resChan
 }
 
+func HandleHangingGoCommand(proc *os.Process) {
+	switch runtime.GOOS {
+	case "linux", "darwin", "freebsd", "netbsd":
+		fmt.Fprintln(os.Stderr, `DETECTED A HANGING GO COMMAND
+
+The gopls test runner has detected a hanging go command. In order to debug
+this, the output of ps and lsof/fstat is printed below.
+
+See golang/go#54461 for more details.`)
+
+		fmt.Fprintln(os.Stderr, "\nps axo ppid,pid,command:")
+		fmt.Fprintln(os.Stderr, "-------------------------")
+		psCmd := exec.Command("ps", "axo", "ppid,pid,command")
+		psCmd.Stdout = os.Stderr
+		psCmd.Stderr = os.Stderr
+		if err := psCmd.Run(); err != nil {
+			panic(fmt.Sprintf("running ps: %v", err))
+		}
+
+		listFiles := "lsof"
+		if runtime.GOOS == "freebsd" || runtime.GOOS == "netbsd" {
+			listFiles = "fstat"
+		}
+
+		fmt.Fprintln(os.Stderr, "\n"+listFiles+":")
+		fmt.Fprintln(os.Stderr, "-----")
+		listFilesCmd := exec.Command(listFiles)
+		listFilesCmd.Stdout = os.Stderr
+		listFilesCmd.Stderr = os.Stderr
+		if err := listFilesCmd.Run(); err != nil {
+			panic(fmt.Sprintf("running %s: %v", listFiles, err))
+		}
+	}
+	panic(fmt.Sprintf("detected hanging go command (pid %d): see golang/go#54461 for more details", proc.Pid))
+}
+
 func cmdDebugStr(cmd *exec.Cmd) string {
 	env := make(map[string]string)
 	for _, kv := range cmd.Env {

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

@@ -7,11 +7,19 @@ package gocommand
 import (
 	"context"
 	"fmt"
+	"regexp"
 	"strings"
 )
 
-// GoVersion checks the go version by running "go list" with modules off.
-// It returns the X in Go 1.X.
+// GoVersion reports the minor version number of the highest release
+// tag built into the go command on the PATH.
+//
+// Note that this may be higher than the version of the go tool used
+// to build this application, and thus the versions of the standard
+// go/{scanner,parser,ast,types} packages that are linked into it.
+// In that case, callers should either downgrade to the version of
+// go used to build the application, or report an error that the
+// application is too old to use the go command on the PATH.
 func GoVersion(ctx context.Context, inv Invocation, r *Runner) (int, error) {
 	inv.Verb = "list"
 	inv.Args = []string{"-e", "-f", `{{context.ReleaseTags}}`, `--`, `unsafe`}
@@ -38,7 +46,7 @@ func GoVersion(ctx context.Context, inv Invocation, r *Runner) (int, error) {
 	if len(stdout) < 3 {
 		return 0, fmt.Errorf("bad ReleaseTags output: %q", stdout)
 	}
-	// Split up "[go1.1 go1.15]"
+	// Split up "[go1.1 go1.15]" and return highest go1.X value.
 	tags := strings.Fields(stdout[1 : len(stdout)-2])
 	for i := len(tags) - 1; i >= 0; i-- {
 		var version int
@@ -49,3 +57,25 @@ func GoVersion(ctx context.Context, inv Invocation, r *Runner) (int, error) {
 	}
 	return 0, fmt.Errorf("no parseable ReleaseTags in %v", tags)
 }
+
+// GoVersionOutput returns the complete output of the go version command.
+func GoVersionOutput(ctx context.Context, inv Invocation, r *Runner) (string, error) {
+	inv.Verb = "version"
+	goVersion, err := r.Run(ctx, inv)
+	if err != nil {
+		return "", err
+	}
+	return goVersion.String(), nil
+}
+
+// ParseGoVersionOutput extracts the Go version string
+// from the output of the "go version" command.
+// Given an unrecognized form, it returns an empty string.
+func ParseGoVersionOutput(data string) string {
+	re := regexp.MustCompile(`^go version (go\S+|devel \S+)`)
+	m := re.FindStringSubmatch(data)
+	if len(m) != 2 {
+		return "" // unrecognized version
+	}
+	return m[1]
+}

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

@@ -6,9 +6,11 @@ package pkgbits
 
 import (
 	"encoding/binary"
+	"errors"
 	"fmt"
 	"go/constant"
 	"go/token"
+	"io"
 	"math/big"
 	"os"
 	"runtime"
@@ -51,6 +53,8 @@ type PkgDecoder struct {
 	// 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
+
+	scratchRelocEnt []RelocEnt
 }
 
 // PkgPath returns the package path for the package
@@ -94,7 +98,7 @@ func NewPkgDecoder(pkgPath, input string) PkgDecoder {
 	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)
+	pos, err := r.Seek(0, io.SeekCurrent)
 	assert(err == nil)
 
 	pr.elemData = input[pos:]
@@ -164,6 +168,21 @@ func (pr *PkgDecoder) NewDecoder(k RelocKind, idx Index, marker SyncMarker) Deco
 	return r
 }
 
+// TempDecoder returns a Decoder for the given (section, index) pair,
+// and decodes the given SyncMarker from the element bitstream.
+// If possible the Decoder should be RetireDecoder'd when it is no longer
+// needed, this will avoid heap allocations.
+func (pr *PkgDecoder) TempDecoder(k RelocKind, idx Index, marker SyncMarker) Decoder {
+	r := pr.TempDecoderRaw(k, idx)
+	r.Sync(marker)
+	return r
+}
+
+func (pr *PkgDecoder) RetireDecoder(d *Decoder) {
+	pr.scratchRelocEnt = d.Relocs
+	d.Relocs = nil
+}
+
 // NewDecoderRaw returns a Decoder for the given (section, index) pair.
 //
 // Most callers should use NewDecoder instead.
@@ -187,6 +206,30 @@ func (pr *PkgDecoder) NewDecoderRaw(k RelocKind, idx Index) Decoder {
 	return r
 }
 
+func (pr *PkgDecoder) TempDecoderRaw(k RelocKind, idx Index) Decoder {
+	r := Decoder{
+		common: pr,
+		k:      k,
+		Idx:    idx,
+	}
+
+	r.Data.Reset(pr.DataIdx(k, idx))
+	r.Sync(SyncRelocs)
+	l := r.Len()
+	if cap(pr.scratchRelocEnt) >= l {
+		r.Relocs = pr.scratchRelocEnt[:l]
+		pr.scratchRelocEnt = nil
+	} else {
+		r.Relocs = make([]RelocEnt, l)
+	}
+	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 {
@@ -206,11 +249,39 @@ func (r *Decoder) checkErr(err error) {
 }
 
 func (r *Decoder) rawUvarint() uint64 {
-	x, err := binary.ReadUvarint(&r.Data)
+	x, err := readUvarint(&r.Data)
 	r.checkErr(err)
 	return x
 }
 
+// readUvarint is a type-specialized copy of encoding/binary.ReadUvarint.
+// This avoids the interface conversion and thus has better escape properties,
+// which flows up the stack.
+func readUvarint(r *strings.Reader) (uint64, error) {
+	var x uint64
+	var s uint
+	for i := 0; i < binary.MaxVarintLen64; i++ {
+		b, err := r.ReadByte()
+		if err != nil {
+			if i > 0 && err == io.EOF {
+				err = io.ErrUnexpectedEOF
+			}
+			return x, err
+		}
+		if b < 0x80 {
+			if i == binary.MaxVarintLen64-1 && b > 1 {
+				return x, overflow
+			}
+			return x | uint64(b)<<s, nil
+		}
+		x |= uint64(b&0x7f) << s
+		s += 7
+	}
+	return x, overflow
+}
+
+var overflow = errors.New("pkgbits: readUvarint overflows a 64-bit integer")
+
 func (r *Decoder) rawVarint() int64 {
 	ux := r.rawUvarint()
 
@@ -237,7 +308,7 @@ func (r *Decoder) Sync(mWant SyncMarker) {
 		return
 	}
 
-	pos, _ := r.Data.Seek(0, os.SEEK_CUR) // TODO(mdempsky): io.SeekCurrent after #44505 is resolved
+	pos, _ := r.Data.Seek(0, io.SeekCurrent)
 	mHave := SyncMarker(r.rawUvarint())
 	writerPCs := make([]int, r.rawUvarint())
 	for i := range writerPCs {
@@ -302,7 +373,7 @@ func (r *Decoder) Int64() int64 {
 	return r.rawVarint()
 }
 
-// Int64 decodes and returns a uint64 value from the element bitstream.
+// Uint64 decodes and returns a uint64 value from the element bitstream.
 func (r *Decoder) Uint64() uint64 {
 	r.Sync(SyncUint64)
 	return r.rawUvarint()
@@ -409,8 +480,12 @@ func (r *Decoder) bigFloat() *big.Float {
 // 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()
+	var path string
+	{
+		r := pr.TempDecoder(RelocPkg, idx, SyncPkgDef)
+		path = r.String()
+		pr.RetireDecoder(&r)
+	}
 	if path == "" {
 		path = pr.pkgPath
 	}
@@ -420,14 +495,23 @@ func (pr *PkgDecoder) PeekPkgPath(idx Index) string {
 // 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()
+	var ridx Index
+	var name string
+	var rcode int
+	{
+		r := pr.TempDecoder(RelocName, idx, SyncObject1)
+		r.Sync(SyncSym)
+		r.Sync(SyncPkg)
+		ridx = r.Reloc(RelocPkg)
+		name = r.String()
+		rcode = r.Code(SyncCodeObj)
+		pr.RetireDecoder(&r)
+	}
+
+	path := pr.PeekPkgPath(ridx)
 	assert(name != "")
 
-	tag := CodeObj(r.Code(SyncCodeObj))
+	tag := CodeObj(rcode)
 
 	return path, name, tag
 }

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

@@ -147,8 +147,9 @@ func (pw *PkgEncoder) NewEncoderRaw(k RelocKind) Encoder {
 type Encoder struct {
 	p *PkgEncoder
 
-	Relocs []RelocEnt
-	Data   bytes.Buffer // accumulated element bitstream data
+	Relocs   []RelocEnt
+	RelocMap map[RelocEnt]uint32
+	Data     bytes.Buffer // accumulated element bitstream data
 
 	encodingRelocHeader bool
 
@@ -210,15 +211,18 @@ func (w *Encoder) rawVarint(x int64) {
 }
 
 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
+	e := RelocEnt{r, idx}
+	if w.RelocMap != nil {
+		if i, ok := w.RelocMap[e]; ok {
+			return int(i)
 		}
+	} else {
+		w.RelocMap = make(map[RelocEnt]uint32)
 	}
 
 	i := len(w.Relocs)
-	w.Relocs = append(w.Relocs, RelocEnt{r, idx})
+	w.RelocMap[e] = uint32(i)
+	w.Relocs = append(w.Relocs, e)
 	return i
 }
 
@@ -289,7 +293,7 @@ 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.
+// Uint 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,

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

@@ -5,11 +5,11 @@
 package pkgbits
 
 // A RelocKind indicates a particular section within a unified IR export.
-type RelocKind int
+type RelocKind int32
 
 // An Index represents a bitstream element index within a particular
 // section.
-type Index int
+type Index int32
 
 // A relocEnt (relocation entry) is an entry in an element's local
 // reference table.

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

@@ -0,0 +1,59 @@
+// Copyright 2023 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 tokeninternal provides access to some internal features of the token
+// package.
+package tokeninternal
+
+import (
+	"go/token"
+	"sync"
+	"unsafe"
+)
+
+// GetLines returns the table of line-start offsets from a token.File.
+func GetLines(file *token.File) []int {
+	// token.File has a Lines method on Go 1.21 and later.
+	if file, ok := (interface{})(file).(interface{ Lines() []int }); ok {
+		return file.Lines()
+	}
+
+	// This declaration must match that of token.File.
+	// This creates a risk of dependency skew.
+	// For now we check that the size of the two
+	// declarations is the same, on the (fragile) assumption
+	// that future changes would add fields.
+	type tokenFile119 struct {
+		_     string
+		_     int
+		_     int
+		mu    sync.Mutex // we're not complete monsters
+		lines []int
+		_     []struct{}
+	}
+	type tokenFile118 struct {
+		_ *token.FileSet // deleted in go1.19
+		tokenFile119
+	}
+
+	type uP = unsafe.Pointer
+	switch unsafe.Sizeof(*file) {
+	case unsafe.Sizeof(tokenFile118{}):
+		var ptr *tokenFile118
+		*(*uP)(uP(&ptr)) = uP(file)
+		ptr.mu.Lock()
+		defer ptr.mu.Unlock()
+		return ptr.lines
+
+	case unsafe.Sizeof(tokenFile119{}):
+		var ptr *tokenFile119
+		*(*uP)(uP(&ptr)) = uP(file)
+		ptr.mu.Lock()
+		defer ptr.mu.Unlock()
+		return ptr.lines
+
+	default:
+		panic("unexpected token.File size")
+	}
+}

vendor/golang.org/x/tools/internal/typesinternal/errorcode.go

@@ -30,6 +30,12 @@ type ErrorCode int
 // convention that "bad" implies a problem with syntax, and "invalid" implies a
 // problem with types.
 
+const (
+	// InvalidSyntaxTree occurs if an invalid syntax tree is provided
+	// to the type checker. It should never happen.
+	InvalidSyntaxTree ErrorCode = -1
+)
+
 const (
 	_ ErrorCode = iota
 
@@ -153,12 +159,12 @@ const (
 
 	/* decls > var (+ other variable assignment codes) */
 
-	// UntypedNil occurs when the predeclared (untyped) value nil is used to
+	// UntypedNilUse occurs when the predeclared (untyped) value nil is used to
 	// initialize a variable declared without an explicit type.
 	//
 	// Example:
 	//  var x = nil
-	UntypedNil
+	UntypedNilUse
 
 	// WrongAssignCount occurs when the number of values on the right-hand side
 	// of an assignment or or initialization expression does not match the number
@@ -1523,4 +1529,32 @@ const (
 	// Example:
 	//  type T[P any] struct{ *P }
 	MisplacedTypeParam
+
+	// InvalidUnsafeSliceData occurs when unsafe.SliceData is called with
+	// an argument that is not of slice type. It also occurs if it is used
+	// in a package compiled for a language version before go1.20.
+	//
+	// Example:
+	//  import "unsafe"
+	//
+	//  var x int
+	//  var _ = unsafe.SliceData(x)
+	InvalidUnsafeSliceData
+
+	// InvalidUnsafeString occurs when unsafe.String is called with
+	// a length argument that is not of integer type, negative, or
+	// out of bounds. It also occurs if it is used in a package
+	// compiled for a language version before go1.20.
+	//
+	// Example:
+	//  import "unsafe"
+	//
+	//  var b [10]byte
+	//  var _ = unsafe.String(&b[0], -1)
+	InvalidUnsafeString
+
+	// InvalidUnsafeStringData occurs if it is used in a package
+	// compiled for a language version before go1.20.
+	_ // not used anymore
+
 )

vendor/golang.org/x/tools/internal/typesinternal/errorcode_string.go

@@ -8,6 +8,7 @@ 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[InvalidSyntaxTree - -1]
 	_ = x[Test-1]
 	_ = x[BlankPkgName-2]
 	_ = x[MismatchedPkgName-3]
@@ -23,7 +24,7 @@ func _() {
 	_ = x[InvalidConstInit-13]
 	_ = x[InvalidConstVal-14]
 	_ = x[InvalidConstType-15]
-	_ = x[UntypedNil-16]
+	_ = x[UntypedNilUse-16]
 	_ = x[WrongAssignCount-17]
 	_ = x[UnassignableOperand-18]
 	_ = x[NoNewVar-19]
@@ -152,16 +153,27 @@ func _() {
 	_ = x[MisplacedConstraintIface-142]
 	_ = x[InvalidMethodTypeParams-143]
 	_ = x[MisplacedTypeParam-144]
+	_ = x[InvalidUnsafeSliceData-145]
+	_ = x[InvalidUnsafeString-146]
 }
 
-const _ErrorCode_name = "TestBlankPkgNameMismatchedPkgNameInvalidPkgUseBadImportPathBrokenImportImportCRenamedUnusedImportInvalidInitCycleDuplicateDeclInvalidDeclCycleInvalidTypeCycleInvalidConstInitInvalidConstValInvalidConstTypeUntypedNilWrongAssignCountUnassignableOperandNoNewVarMultiValAssignOpInvalidIfaceAssignInvalidChanAssignIncompatibleAssignUnaddressableFieldAssignNotATypeInvalidArrayLenBlankIfaceMethodIncomparableMapKeyInvalidIfaceEmbedInvalidPtrEmbedBadRecvInvalidRecvDuplicateFieldAndMethodDuplicateMethodInvalidBlankInvalidIotaMissingInitBodyInvalidInitSigInvalidInitDeclInvalidMainDeclTooManyValuesNotAnExprTruncatedFloatNumericOverflowUndefinedOpMismatchedTypesDivByZeroNonNumericIncDecUnaddressableOperandInvalidIndirectionNonIndexableOperandInvalidIndexSwappedSliceIndicesNonSliceableOperandInvalidSliceExprInvalidShiftCountInvalidShiftOperandInvalidReceiveInvalidSendDuplicateLitKeyMissingLitKeyInvalidLitIndexOversizeArrayLitMixedStructLitInvalidStructLitMissingLitFieldDuplicateLitFieldUnexportedLitFieldInvalidLitFieldUntypedLitInvalidLitAmbiguousSelectorUndeclaredImportedNameUnexportedNameUndeclaredNameMissingFieldOrMethodBadDotDotDotSyntaxNonVariadicDotDotDotMisplacedDotDotDotInvalidDotDotDotOperandInvalidDotDotDotUncalledBuiltinInvalidAppendInvalidCapInvalidCloseInvalidCopyInvalidComplexInvalidDeleteInvalidImagInvalidLenSwappedMakeArgsInvalidMakeInvalidRealInvalidAssertImpossibleAssertInvalidConversionInvalidUntypedConversionBadOffsetofSyntaxInvalidOffsetofUnusedExprUnusedVarMissingReturnWrongResultCountOutOfScopeResultInvalidCondInvalidPostDeclInvalidChanRangeInvalidIterVarInvalidRangeExprMisplacedBreakMisplacedContinueMisplacedFallthroughDuplicateCaseDuplicateDefaultBadTypeKeywordInvalidTypeSwitchInvalidExprSwitchInvalidSelectCaseUndeclaredLabelDuplicateLabelMisplacedLabelUnusedLabelJumpOverDeclJumpIntoBlockInvalidMethodExprWrongArgCountInvalidCallUnusedResultsInvalidDeferInvalidGoBadDeclRepeatedDeclInvalidUnsafeAddInvalidUnsafeSliceUnsupportedFeatureNotAGenericTypeWrongTypeArgCountCannotInferTypeArgsInvalidTypeArgInvalidInstanceCycleInvalidUnionMisplacedConstraintIfaceInvalidMethodTypeParamsMisplacedTypeParam"
+const (
+	_ErrorCode_name_0 = "InvalidSyntaxTree"
+	_ErrorCode_name_1 = "TestBlankPkgNameMismatchedPkgNameInvalidPkgUseBadImportPathBrokenImportImportCRenamedUnusedImportInvalidInitCycleDuplicateDeclInvalidDeclCycleInvalidTypeCycleInvalidConstInitInvalidConstValInvalidConstTypeUntypedNilUseWrongAssignCountUnassignableOperandNoNewVarMultiValAssignOpInvalidIfaceAssignInvalidChanAssignIncompatibleAssignUnaddressableFieldAssignNotATypeInvalidArrayLenBlankIfaceMethodIncomparableMapKeyInvalidIfaceEmbedInvalidPtrEmbedBadRecvInvalidRecvDuplicateFieldAndMethodDuplicateMethodInvalidBlankInvalidIotaMissingInitBodyInvalidInitSigInvalidInitDeclInvalidMainDeclTooManyValuesNotAnExprTruncatedFloatNumericOverflowUndefinedOpMismatchedTypesDivByZeroNonNumericIncDecUnaddressableOperandInvalidIndirectionNonIndexableOperandInvalidIndexSwappedSliceIndicesNonSliceableOperandInvalidSliceExprInvalidShiftCountInvalidShiftOperandInvalidReceiveInvalidSendDuplicateLitKeyMissingLitKeyInvalidLitIndexOversizeArrayLitMixedStructLitInvalidStructLitMissingLitFieldDuplicateLitFieldUnexportedLitFieldInvalidLitFieldUntypedLitInvalidLitAmbiguousSelectorUndeclaredImportedNameUnexportedNameUndeclaredNameMissingFieldOrMethodBadDotDotDotSyntaxNonVariadicDotDotDotMisplacedDotDotDotInvalidDotDotDotOperandInvalidDotDotDotUncalledBuiltinInvalidAppendInvalidCapInvalidCloseInvalidCopyInvalidComplexInvalidDeleteInvalidImagInvalidLenSwappedMakeArgsInvalidMakeInvalidRealInvalidAssertImpossibleAssertInvalidConversionInvalidUntypedConversionBadOffsetofSyntaxInvalidOffsetofUnusedExprUnusedVarMissingReturnWrongResultCountOutOfScopeResultInvalidCondInvalidPostDeclInvalidChanRangeInvalidIterVarInvalidRangeExprMisplacedBreakMisplacedContinueMisplacedFallthroughDuplicateCaseDuplicateDefaultBadTypeKeywordInvalidTypeSwitchInvalidExprSwitchInvalidSelectCaseUndeclaredLabelDuplicateLabelMisplacedLabelUnusedLabelJumpOverDeclJumpIntoBlockInvalidMethodExprWrongArgCountInvalidCallUnusedResultsInvalidDeferInvalidGoBadDeclRepeatedDeclInvalidUnsafeAddInvalidUnsafeSliceUnsupportedFeatureNotAGenericTypeWrongTypeArgCountCannotInferTypeArgsInvalidTypeArgInvalidInstanceCycleInvalidUnionMisplacedConstraintIfaceInvalidMethodTypeParamsMisplacedTypeParamInvalidUnsafeSliceDataInvalidUnsafeString"
+)
 
-var _ErrorCode_index = [...]uint16{0, 4, 16, 33, 46, 59, 71, 85, 97, 113, 126, 142, 158, 174, 189, 205, 215, 231, 250, 258, 274, 292, 309, 327, 351, 359, 374, 390, 408, 425, 440, 447, 458, 481, 496, 508, 519, 534, 548, 563, 578, 591, 600, 614, 629, 640, 655, 664, 680, 700, 718, 737, 749, 768, 787, 803, 820, 839, 853, 864, 879, 892, 907, 923, 937, 953, 968, 985, 1003, 1018, 1028, 1038, 1055, 1077, 1091, 1105, 1125, 1143, 1163, 1181, 1204, 1220, 1235, 1248, 1258, 1270, 1281, 1295, 1308, 1319, 1329, 1344, 1355, 1366, 1379, 1395, 1412, 1436, 1453, 1468, 1478, 1487, 1500, 1516, 1532, 1543, 1558, 1574, 1588, 1604, 1618, 1635, 1655, 1668, 1684, 1698, 1715, 1732, 1749, 1764, 1778, 1792, 1803, 1815, 1828, 1845, 1858, 1869, 1882, 1894, 1903, 1910, 1922, 1938, 1956, 1974, 1989, 2006, 2025, 2039, 2059, 2071, 2095, 2118, 2136}
+var (
+	_ErrorCode_index_1 = [...]uint16{0, 4, 16, 33, 46, 59, 71, 85, 97, 113, 126, 142, 158, 174, 189, 205, 218, 234, 253, 261, 277, 295, 312, 330, 354, 362, 377, 393, 411, 428, 443, 450, 461, 484, 499, 511, 522, 537, 551, 566, 581, 594, 603, 617, 632, 643, 658, 667, 683, 703, 721, 740, 752, 771, 790, 806, 823, 842, 856, 867, 882, 895, 910, 926, 940, 956, 971, 988, 1006, 1021, 1031, 1041, 1058, 1080, 1094, 1108, 1128, 1146, 1166, 1184, 1207, 1223, 1238, 1251, 1261, 1273, 1284, 1298, 1311, 1322, 1332, 1347, 1358, 1369, 1382, 1398, 1415, 1439, 1456, 1471, 1481, 1490, 1503, 1519, 1535, 1546, 1561, 1577, 1591, 1607, 1621, 1638, 1658, 1671, 1687, 1701, 1718, 1735, 1752, 1767, 1781, 1795, 1806, 1818, 1831, 1848, 1861, 1872, 1885, 1897, 1906, 1913, 1925, 1941, 1959, 1977, 1992, 2009, 2028, 2042, 2062, 2074, 2098, 2121, 2139, 2161, 2180}
+)
 
 func (i ErrorCode) String() string {
-	i -= 1
-	if i < 0 || i >= ErrorCode(len(_ErrorCode_index)-1) {
-		return "ErrorCode(" + strconv.FormatInt(int64(i+1), 10) + ")"
+	switch {
+	case i == -1:
+		return _ErrorCode_name_0
+	case 1 <= i && i <= 146:
+		i -= 1
+		return _ErrorCode_name_1[_ErrorCode_index_1[i]:_ErrorCode_index_1[i+1]]
+	default:
+		return "ErrorCode(" + strconv.FormatInt(int64(i), 10) + ")"
 	}
-	return _ErrorCode_name[_ErrorCode_index[i]:_ErrorCode_index[i+1]]
 }