Update dependencies (#333)

6 files changed, 402 insertions, 64 deletions

diff --git a/vendor/golang.org/x/tools/go/internal/gcimporter/bexport.go b/vendor/golang.org/x/tools/go/internal/gcimporter/bexport.go
index a807d0aaa..072005af8 100644
--- a/vendor/golang.org/x/tools/go/internal/gcimporter/bexport.go
+++ b/vendor/golang.org/x/tools/go/internal/gcimporter/bexport.go
@@ -92,16 +92,18 @@ func internalErrorf(format string, args ...interface{}) error {
 // BExportData returns binary export data for pkg.
 // If no file set is provided, position info will be missing.
 func BExportData(fset *token.FileSet, pkg *types.Package) (b []byte, err error) {
-	defer func() {
-		if e := recover(); e != nil {
-			if ierr, ok := e.(internalError); ok {
-				err = ierr
-				return
+	if !debug {
+		defer func() {
+			if e := recover(); e != nil {
+				if ierr, ok := e.(internalError); ok {
+					err = ierr
+					return
+				}
+				// Not an internal error; panic again.
+				panic(e)
 			}
-			// Not an internal error; panic again.
-			panic(e)
-		}
-	}()
+		}()
+	}
 
 	p := exporter{
 		fset:          fset,
diff --git a/vendor/golang.org/x/tools/go/internal/gcimporter/bimport.go b/vendor/golang.org/x/tools/go/internal/gcimporter/bimport.go
index e9f73d14a..b02312000 100644
--- a/vendor/golang.org/x/tools/go/internal/gcimporter/bimport.go
+++ b/vendor/golang.org/x/tools/go/internal/gcimporter/bimport.go
@@ -1029,6 +1029,7 @@ func predeclared() []types.Type {
 			// used internally by gc; never used by this package or in .a files
 			anyType{},
 		}
+		predecl = append(predecl, additionalPredeclared()...)
 	})
 	return predecl
 }
diff --git a/vendor/golang.org/x/tools/go/internal/gcimporter/iexport.go b/vendor/golang.org/x/tools/go/internal/gcimporter/iexport.go
index d2fc8b6fa..be8b7459a 100644
--- a/vendor/golang.org/x/tools/go/internal/gcimporter/iexport.go
+++ b/vendor/golang.org/x/tools/go/internal/gcimporter/iexport.go
@@ -19,11 +19,9 @@ import (
 	"math/big"
 	"reflect"
 	"sort"
-)
 
-// Current indexed export format version. Increase with each format change.
-// 0: Go1.11 encoding
-const iexportVersion = 0
+	"golang.org/x/tools/internal/typeparams"
+)
 
 // Current bundled export format version. Increase with each format change.
 // 0: initial implementation
@@ -44,16 +42,18 @@ func IExportBundle(out io.Writer, fset *token.FileSet, pkgs []*types.Package) er
 }
 
 func iexportCommon(out io.Writer, fset *token.FileSet, bundle bool, pkgs []*types.Package) (err error) {
-	defer func() {
-		if e := recover(); e != nil {
-			if ierr, ok := e.(internalError); ok {
-				err = ierr
-				return
+	if !debug {
+		defer func() {
+			if e := recover(); e != nil {
+				if ierr, ok := e.(internalError); ok {
+					err = ierr
+					return
+				}
+				// Not an internal error; panic again.
+				panic(e)
 			}
-			// Not an internal error; panic again.
-			panic(e)
-		}
-	}()
+		}()
+	}
 
 	p := iexporter{
 		fset:        fset,
@@ -158,7 +158,7 @@ func (w *exportWriter) writeIndex(index map[types.Object]uint64) {
 		pkgs = append(pkgs, pkg)
 
 		sort.Slice(objs, func(i, j int) bool {
-			return objs[i].Name() < objs[j].Name()
+			return indexName(objs[i]) < indexName(objs[j])
 		})
 	}
 
@@ -175,12 +175,26 @@ func (w *exportWriter) writeIndex(index map[types.Object]uint64) {
 		objs := pkgObjs[pkg]
 		w.uint64(uint64(len(objs)))
 		for _, obj := range objs {
-			w.string(obj.Name())
+			w.string(indexName(obj))
 			w.uint64(index[obj])
 		}
 	}
 }
 
+// indexName returns the 'indexed' name of an object. It differs from
+// obj.Name() only for type parameter names, where we include the subscripted
+// type parameter ID.
+//
+// TODO(rfindley): remove this once we no longer need subscripts.
+func indexName(obj types.Object) (res string) {
+	if _, ok := obj.(*types.TypeName); ok {
+		if tparam, ok := obj.Type().(*typeparams.TypeParam); ok {
+			return types.TypeString(tparam, func(*types.Package) string { return "" })
+		}
+	}
+	return obj.Name()
+}
+
 type iexporter struct {
 	fset *token.FileSet
 	out  *bytes.Buffer
@@ -233,10 +247,11 @@ func (p *iexporter) pushDecl(obj types.Object) {
 type exportWriter struct {
 	p *iexporter
 
-	data     intWriter
-	currPkg  *types.Package
-	prevFile string
-	prevLine int64
+	data       intWriter
+	currPkg    *types.Package
+	prevFile   string
+	prevLine   int64
+	prevColumn int64
 }
 
 func (w *exportWriter) exportPath(pkg *types.Package) string {
@@ -261,8 +276,23 @@ func (p *iexporter) doDecl(obj types.Object) {
 		if sig.Recv() != nil {
 			panic(internalErrorf("unexpected method: %v", sig))
 		}
-		w.tag('F')
+
+		// Function.
+		if typeparams.ForSignature(sig).Len() == 0 {
+			w.tag('F')
+		} else {
+			w.tag('G')
+		}
 		w.pos(obj.Pos())
+		// The tparam list of the function type is the
+		// declaration of the type params. So, write out the type
+		// params right now. Then those type params will be
+		// referenced via their type offset (via typOff) in all
+		// other places in the signature and function that they
+		// are used.
+		if tparams := typeparams.ForSignature(sig); tparams.Len() > 0 {
+			w.tparamList(tparams, obj.Pkg())
+		}
 		w.signature(sig)
 
 	case *types.Const:
@@ -271,30 +301,46 @@ func (p *iexporter) doDecl(obj types.Object) {
 		w.value(obj.Type(), obj.Val())
 
 	case *types.TypeName:
+		t := obj.Type()
+
+		if tparam, ok := t.(*typeparams.TypeParam); ok {
+			w.tag('P')
+			w.pos(obj.Pos())
+			w.typ(tparam.Constraint(), obj.Pkg())
+			break
+		}
+
 		if obj.IsAlias() {
 			w.tag('A')
 			w.pos(obj.Pos())
-			w.typ(obj.Type(), obj.Pkg())
+			w.typ(t, obj.Pkg())
 			break
 		}
 
 		// Defined type.
-		w.tag('T')
+		named, ok := t.(*types.Named)
+		if !ok {
+			panic(internalErrorf("%s is not a defined type", t))
+		}
+
+		if typeparams.ForNamed(named).Len() == 0 {
+			w.tag('T')
+		} else {
+			w.tag('U')
+		}
 		w.pos(obj.Pos())
 
+		if typeparams.ForNamed(named).Len() > 0 {
+			w.tparamList(typeparams.ForNamed(named), obj.Pkg())
+		}
+
 		underlying := obj.Type().Underlying()
 		w.typ(underlying, obj.Pkg())
 
-		t := obj.Type()
 		if types.IsInterface(t) {
 			break
 		}
 
-		named, ok := t.(*types.Named)
-		if !ok {
-			panic(internalErrorf("%s is not a defined type", t))
-		}
-
 		n := named.NumMethods()
 		w.uint64(uint64(n))
 		for i := 0; i < n; i++ {
@@ -318,6 +364,48 @@ func (w *exportWriter) tag(tag byte) {
 }
 
 func (w *exportWriter) pos(pos token.Pos) {
+	if iexportVersion >= iexportVersionPosCol {
+		w.posV1(pos)
+	} else {
+		w.posV0(pos)
+	}
+}
+
+func (w *exportWriter) posV1(pos token.Pos) {
+	if w.p.fset == nil {
+		w.int64(0)
+		return
+	}
+
+	p := w.p.fset.Position(pos)
+	file := p.Filename
+	line := int64(p.Line)
+	column := int64(p.Column)
+
+	deltaColumn := (column - w.prevColumn) << 1
+	deltaLine := (line - w.prevLine) << 1
+
+	if file != w.prevFile {
+		deltaLine |= 1
+	}
+	if deltaLine != 0 {
+		deltaColumn |= 1
+	}
+
+	w.int64(deltaColumn)
+	if deltaColumn&1 != 0 {
+		w.int64(deltaLine)
+		if deltaLine&1 != 0 {
+			w.string(file)
+		}
+	}
+
+	w.prevFile = file
+	w.prevLine = line
+	w.prevColumn = column
+}
+
+func (w *exportWriter) posV0(pos token.Pos) {
 	if w.p.fset == nil {
 		w.int64(0)
 		return
@@ -361,8 +449,7 @@ func (w *exportWriter) pkg(pkg *types.Package) {
 func (w *exportWriter) qualifiedIdent(obj types.Object) {
 	// Ensure any referenced declarations are written out too.
 	w.p.pushDecl(obj)
-
-	w.string(obj.Name())
+	w.string(indexName(obj))
 	w.pkg(obj.Pkg())
 }
 
@@ -398,9 +485,22 @@ func (w *exportWriter) startType(k itag) {
 func (w *exportWriter) doTyp(t types.Type, pkg *types.Package) {
 	switch t := t.(type) {
 	case *types.Named:
+		if targs := typeparams.NamedTypeArgs(t); targs.Len() > 0 {
+			w.startType(instanceType)
+			// TODO(rfindley): investigate if this position is correct, and if it
+			// matters.
+			w.pos(t.Obj().Pos())
+			w.typeList(targs, pkg)
+			w.typ(typeparams.NamedTypeOrigin(t), pkg)
+			return
+		}
 		w.startType(definedType)
 		w.qualifiedIdent(t.Obj())
 
+	case *typeparams.TypeParam:
+		w.startType(typeParamType)
+		w.qualifiedIdent(t.Obj())
+
 	case *types.Pointer:
 		w.startType(pointerType)
 		w.typ(t.Elem(), pkg)
@@ -461,9 +561,14 @@ func (w *exportWriter) doTyp(t types.Type, pkg *types.Package) {
 		n := t.NumEmbeddeds()
 		w.uint64(uint64(n))
 		for i := 0; i < n; i++ {
-			f := t.Embedded(i)
-			w.pos(f.Obj().Pos())
-			w.typ(f.Obj().Type(), f.Obj().Pkg())
+			ft := t.EmbeddedType(i)
+			tPkg := pkg
+			if named, _ := ft.(*types.Named); named != nil {
+				w.pos(named.Obj().Pos())
+			} else {
+				w.pos(token.NoPos)
+			}
+			w.typ(ft, tPkg)
 		}
 
 		n = t.NumExplicitMethods()
@@ -476,6 +581,16 @@ func (w *exportWriter) doTyp(t types.Type, pkg *types.Package) {
 			w.signature(sig)
 		}
 
+	case *typeparams.Union:
+		w.startType(unionType)
+		nt := t.Len()
+		w.uint64(uint64(nt))
+		for i := 0; i < nt; i++ {
+			term := t.Term(i)
+			w.bool(term.Tilde())
+			w.typ(term.Type(), pkg)
+		}
+
 	default:
 		panic(internalErrorf("unexpected type: %v, %v", t, reflect.TypeOf(t)))
 	}
@@ -497,6 +612,21 @@ func (w *exportWriter) signature(sig *types.Signature) {
 	}
 }
 
+func (w *exportWriter) typeList(ts *typeparams.TypeList, pkg *types.Package) {
+	w.uint64(uint64(ts.Len()))
+	for i := 0; i < ts.Len(); i++ {
+		w.typ(ts.At(i), pkg)
+	}
+}
+
+func (w *exportWriter) tparamList(list *typeparams.TypeParamList, pkg *types.Package) {
+	ll := uint64(list.Len())
+	w.uint64(ll)
+	for i := 0; i < list.Len(); i++ {
+		w.typ(list.At(i), pkg)
+	}
+}
+
 func (w *exportWriter) paramList(tup *types.Tuple) {
 	n := tup.Len()
 	w.uint64(uint64(n))
@@ -702,7 +832,7 @@ func (w *exportWriter) localIdent(obj types.Object) {
 		return
 	}
 
-	name := obj.Name()
+	name := indexName(obj)
 	if name == "_" {
 		w.string("_")
 		return
diff --git a/vendor/golang.org/x/tools/go/internal/gcimporter/iimport.go b/vendor/golang.org/x/tools/go/internal/gcimporter/iimport.go
index 8ed8bc62d..1fcc87e58 100644
--- a/vendor/golang.org/x/tools/go/internal/gcimporter/iimport.go
+++ b/vendor/golang.org/x/tools/go/internal/gcimporter/iimport.go
@@ -18,6 +18,8 @@ import (
 	"go/types"
 	"io"
 	"sort"
+
+	"golang.org/x/tools/internal/typeparams"
 )
 
 type intReader struct {
@@ -41,6 +43,21 @@ func (r *intReader) uint64() uint64 {
 	return i
 }
 
+// Keep this in sync with constants in iexport.go.
+const (
+	iexportVersionGo1_11 = 0
+	iexportVersionPosCol = 1
+	// TODO: before release, change this back to 2.
+	iexportVersionGenerics = iexportVersionPosCol
+
+	iexportVersionCurrent = iexportVersionGenerics
+)
+
+type ident struct {
+	pkg  string
+	name string
+}
+
 const predeclReserved = 32
 
 type itag uint64
@@ -56,6 +73,9 @@ const (
 	signatureType
 	structType
 	interfaceType
+	typeParamType
+	instanceType
+	unionType
 )
 
 // IImportData imports a package from the serialized package data
@@ -78,15 +98,17 @@ func IImportBundle(fset *token.FileSet, imports map[string]*types.Package, data
 func iimportCommon(fset *token.FileSet, imports map[string]*types.Package, data []byte, bundle bool, path string) (pkgs []*types.Package, err error) {
 	const currentVersion = 1
 	version := int64(-1)
-	defer func() {
-		if e := recover(); e != nil {
-			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)
+	if !debug {
+		defer func() {
+			if e := recover(); e != nil {
+				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)
+				}
 			}
-		}
-	}()
+		}()
+	}
 
 	r := &intReader{bytes.NewReader(data), path}
 
@@ -101,9 +123,13 @@ func iimportCommon(fset *token.FileSet, imports map[string]*types.Package, data
 
 	version = int64(r.uint64())
 	switch version {
-	case currentVersion, 0:
+	case /* iexportVersionGenerics, */ iexportVersionPosCol, iexportVersionGo1_11:
 	default:
-		errorf("unknown iexport format version %d", version)
+		if version > iexportVersionGenerics {
+			errorf("unstable iexport format version %d, just rebuild compiler and std library", version)
+		} else {
+			errorf("unknown iexport format version %d", version)
+		}
 	}
 
 	sLen := int64(r.uint64())
@@ -115,8 +141,9 @@ func iimportCommon(fset *token.FileSet, imports map[string]*types.Package, data
 	r.Seek(sLen+dLen, io.SeekCurrent)
 
 	p := iimporter{
-		ipath:   path,
-		version: int(version),
+		exportVersion: version,
+		ipath:         path,
+		version:       int(version),
 
 		stringData:  stringData,
 		stringCache: make(map[uint64]string),
@@ -125,6 +152,9 @@ func iimportCommon(fset *token.FileSet, imports map[string]*types.Package, data
 		declData: declData,
 		pkgIndex: make(map[*types.Package]map[string]uint64),
 		typCache: make(map[uint64]types.Type),
+		// Separate map for typeparams, keyed by their package and unique
+		// name (name with subscript).
+		tparamIndex: make(map[ident]types.Type),
 
 		fake: fakeFileSet{
 			fset:  fset,
@@ -216,16 +246,18 @@ func iimportCommon(fset *token.FileSet, imports map[string]*types.Package, data
 }
 
 type iimporter struct {
-	ipath   string
-	version int
+	exportVersion int64
+	ipath         string
+	version       int
 
 	stringData  []byte
 	stringCache map[uint64]string
 	pkgCache    map[uint64]*types.Package
 
-	declData []byte
-	pkgIndex map[*types.Package]map[string]uint64
-	typCache map[uint64]types.Type
+	declData    []byte
+	pkgIndex    map[*types.Package]map[string]uint64
+	typCache    map[uint64]types.Type
+	tparamIndex map[ident]types.Type
 
 	fake          fakeFileSet
 	interfaceList []*types.Interface
@@ -315,17 +347,27 @@ func (r *importReader) obj(name string) {
 
 		r.declare(types.NewConst(pos, r.currPkg, name, typ, val))
 
-	case 'F':
+	case 'F', 'G':
+		var tparams []*typeparams.TypeParam
+		if tag == 'G' {
+			tparams = r.tparamList()
+		}
 		sig := r.signature(nil)
-
+		typeparams.SetForSignature(sig, tparams)
 		r.declare(types.NewFunc(pos, r.currPkg, name, sig))
 
-	case 'T':
+	case 'T', 'U':
 		// Types can be recursive. We need to setup a stub
 		// declaration before recursing.
 		obj := types.NewTypeName(pos, r.currPkg, name, nil)
 		named := types.NewNamed(obj, nil, nil)
+		// Declare obj before calling r.tparamList, so the new type name is recognized
+		// if used in the constraint of one of its own typeparams (see #48280).
 		r.declare(obj)
+		if tag == 'U' {
+			tparams := r.tparamList()
+			typeparams.SetForNamed(named, tparams)
+		}
 
 		underlying := r.p.typAt(r.uint64(), named).Underlying()
 		named.SetUnderlying(underlying)
@@ -337,10 +379,50 @@ func (r *importReader) obj(name string) {
 				recv := r.param()
 				msig := r.signature(recv)
 
+				// If the receiver has any targs, set those as the
+				// rparams of the method (since those are the
+				// typeparams being used in the method sig/body).
+				targs := typeparams.NamedTypeArgs(baseType(msig.Recv().Type()))
+				if targs.Len() > 0 {
+					rparams := make([]*typeparams.TypeParam, targs.Len())
+					for i := range rparams {
+						// TODO(rfindley): this is less tolerant than the standard library
+						// go/internal/gcimporter, which calls under(...) and is tolerant
+						// of nil rparams. Bring them in sync by making the standard
+						// library importer stricter.
+						rparams[i] = targs.At(i).(*typeparams.TypeParam)
+					}
+					typeparams.SetRecvTypeParams(msig, rparams)
+				}
+
 				named.AddMethod(types.NewFunc(mpos, r.currPkg, mname, msig))
 			}
 		}
 
+	case 'P':
+		// We need to "declare" a typeparam in order to have a name that
+		// can be referenced recursively (if needed) in the type param's
+		// bound.
+		if r.p.exportVersion < iexportVersionGenerics {
+			errorf("unexpected type param type")
+		}
+		name0, sub := parseSubscript(name)
+		tn := types.NewTypeName(pos, r.currPkg, name0, nil)
+		t := typeparams.NewTypeParam(tn, nil)
+		if sub == 0 {
+			errorf("name %q missing subscript", name)
+		}
+
+		// TODO(rfindley): can we use a different, stable ID?
+		// t.SetId(sub)
+
+		// 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}
+		r.p.tparamIndex[id] = t
+
+		typeparams.SetTypeParamConstraint(t, r.typ())
+
 	case 'V':
 		typ := r.typ()
 
@@ -499,7 +581,7 @@ func (r *importReader) qualifiedIdent() (*types.Package, string) {
 }
 
 func (r *importReader) pos() token.Pos {
-	if r.p.version >= 1 {
+	if r.p.exportVersion >= iexportVersionPosCol {
 		r.posv1()
 	} else {
 		r.posv0()
@@ -618,6 +700,49 @@ func (r *importReader) doType(base *types.Named) types.Type {
 		typ := newInterface(methods, embeddeds)
 		r.p.interfaceList = append(r.p.interfaceList, typ)
 		return typ
+
+	case typeParamType:
+		if r.p.exportVersion < iexportVersionGenerics {
+			errorf("unexpected type param type")
+		}
+		pkg, name := r.qualifiedIdent()
+		id := ident{pkg.Name(), name}
+		if t, ok := r.p.tparamIndex[id]; ok {
+			// We're already in the process of importing this typeparam.
+			return t
+		}
+		// Otherwise, import the definition of the typeparam now.
+		r.p.doDecl(pkg, name)
+		return r.p.tparamIndex[id]
+
+	case instanceType:
+		if r.p.exportVersion < iexportVersionGenerics {
+			errorf("unexpected instantiation type")
+		}
+		// pos does not matter for instances: they are positioned on the original
+		// type.
+		_ = r.pos()
+		len := r.uint64()
+		targs := make([]types.Type, len)
+		for i := range targs {
+			targs[i] = r.typ()
+		}
+		baseType := r.typ()
+		// The imported instantiated type doesn't include any methods, so
+		// we must always use the methods of the base (orig) type.
+		// TODO provide a non-nil *Environment
+		t, _ := typeparams.Instantiate(nil, baseType, targs, false)
+		return t
+
+	case unionType:
+		if r.p.exportVersion < iexportVersionGenerics {
+			errorf("unexpected instantiation type")
+		}
+		terms := make([]*typeparams.Term, r.uint64())
+		for i := range terms {
+			terms[i] = typeparams.NewTerm(r.bool(), r.typ())
+		}
+		return typeparams.NewUnion(terms)
 	}
 }
 
@@ -632,6 +757,20 @@ func (r *importReader) signature(recv *types.Var) *types.Signature {
 	return types.NewSignature(recv, params, results, variadic)
 }
 
+func (r *importReader) tparamList() []*typeparams.TypeParam {
+	n := r.uint64()
+	if n == 0 {
+		return nil
+	}
+	xs := make([]*typeparams.TypeParam, n)
+	for i := range xs {
+		// Note: the standard library importer is tolerant of nil types here,
+		// though would panic in SetTypeParams.
+		xs[i] = r.typ().(*typeparams.TypeParam)
+	}
+	return xs
+}
+
 func (r *importReader) paramList() *types.Tuple {
 	xs := make([]*types.Var, r.uint64())
 	for i := range xs {
@@ -674,3 +813,33 @@ func (r *importReader) byte() byte {
 	}
 	return x
 }
+
+func baseType(typ types.Type) *types.Named {
+	// pointer receivers are never types.Named types
+	if p, _ := typ.(*types.Pointer); p != nil {
+		typ = p.Elem()
+	}
+	// receiver base types are always (possibly generic) types.Named types
+	n, _ := typ.(*types.Named)
+	return n
+}
+
+func parseSubscript(name string) (string, uint64) {
+	// Extract the subscript value from the type param name. We export
+	// and import the subscript value, so that all type params have
+	// unique names.
+	sub := uint64(0)
+	startsub := -1
+	for i, r := range name {
+		if '₀' <= r && r < '₀'+10 {
+			if startsub == -1 {
+				startsub = i
+			}
+			sub = sub*10 + uint64(r-'₀')
+		}
+	}
+	if startsub >= 0 {
+		name = name[:startsub]
+	}
+	return name, sub
+}
diff --git a/vendor/golang.org/x/tools/go/internal/gcimporter/support_go117.go b/vendor/golang.org/x/tools/go/internal/gcimporter/support_go117.go
new file mode 100644
index 000000000..817a147ef
--- /dev/null
+++ b/vendor/golang.org/x/tools/go/internal/gcimporter/support_go117.go
@@ -0,0 +1,16 @@
+// 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 !typeparams || !go1.18
+// +build !typeparams !go1.18
+
+package gcimporter
+
+import "go/types"
+
+const iexportVersion = iexportVersionGo1_11
+
+func additionalPredeclared() []types.Type {
+	return nil
+}
diff --git a/vendor/golang.org/x/tools/go/internal/gcimporter/support_go118.go b/vendor/golang.org/x/tools/go/internal/gcimporter/support_go118.go
new file mode 100644
index 000000000..e6b81fc50
--- /dev/null
+++ b/vendor/golang.org/x/tools/go/internal/gcimporter/support_go118.go
@@ -0,0 +1,20 @@
+// 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 typeparams && go1.18
+// +build typeparams,go1.18
+
+package gcimporter
+
+import "go/types"
+
+const iexportVersion = iexportVersionGenerics
+
+// additionalPredeclared returns additional predeclared types in go.1.18.
+func additionalPredeclared() []types.Type {
+	return []types.Type{
+		// comparable
+		types.Universe.Lookup("comparable").Type(),
+	}
+}