gopls: use Func.Signature everywhere

Updates golang/go#65917

Change-Id: I20bec8b0a1778f0d2d81f729d12ba966799c7805
Reviewed-on: https://go-review.googlesource.com/c/tools/+/612037
Reviewed-by: Robert Findley <rfindley@google.com>
Auto-Submit: Alan Donovan <adonovan@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

gopls/internal/cache/methodsets/methodsets.go

@@ -449,7 +449,7 @@ func fingerprint(method *types.Func) (string, bool) {
 	}
 
 	buf.WriteString(method.Id()) // e.g. "pkg.Type"
-	sig := method.Type().(*types.Signature)
+	sig := method.Signature()
 	fprint(sig.Params())
 	fprint(sig.Results())
 	return buf.String(), tricky

gopls/internal/golang/code_lens.go

@@ -129,7 +129,7 @@ func matchTestFunc(fn *ast.FuncDecl, info *types.Info, nameRe *regexp.Regexp, pa
 	if !ok {
 		return false
 	}
-	sig := obj.Type().(*types.Signature)
+	sig := obj.Signature()
 	// Test functions should have only one parameter.
 	if sig.Params().Len() != 1 {
 		return false

gopls/internal/golang/codeaction.go

@@ -597,7 +597,7 @@ func getGoAssemblyAction(view *cache.View, pkg *cache.Package, pgf *parsego.File
 	if len(path) >= 2 { // [... FuncDecl File]
 		if decl, ok := path[len(path)-2].(*ast.FuncDecl); ok {
 			if fn, ok := pkg.TypesInfo().Defs[decl.Name].(*types.Func); ok {
-				sig := fn.Type().(*types.Signature)
+				sig := fn.Signature()
 
 				// Compute the linker symbol of the enclosing function.
 				var sym strings.Builder

gopls/internal/golang/completion/completion.go

@@ -1036,7 +1036,7 @@ func (c *completer) populateCommentCompletions(comment *ast.CommentGroup) {
 
 			// collect receiver struct fields
 			if node.Recv != nil {
-				sig := c.pkg.TypesInfo().Defs[node.Name].(*types.Func).Type().(*types.Signature)
+				sig := c.pkg.TypesInfo().Defs[node.Name].(*types.Func).Signature()
 				_, named := typesinternal.ReceiverNamed(sig.Recv()) // may be nil if ill-typed
 				if named != nil {
 					if recvStruct, ok := named.Underlying().(*types.Struct); ok {

gopls/internal/golang/completion/format.go

@@ -95,7 +95,7 @@ func (c *completer) item(ctx context.Context, cand candidate) (CompletionItem, e
 			break
 		}
 	case *types.Func:
-		if obj.Type().(*types.Signature).Recv() == nil {
+		if obj.Signature().Recv() == nil {
 			kind = protocol.FunctionCompletion
 		} else {
 			kind = protocol.MethodCompletion

gopls/internal/golang/hover.go

@@ -535,7 +535,7 @@ func hover(ctx context.Context, snapshot *cache.Snapshot, fh file.Handle, pp pro
 			var recv types.Object
 			switch obj := obj.(type) {
 			case *types.Func:
-				sig := obj.Type().(*types.Signature)
+				sig := obj.Signature()
 				if sig.Recv() != nil {
 					tname := typeToObject(sig.Recv().Type())
 					if tname != nil { // beware typed nil
@@ -962,7 +962,7 @@ func objectString(obj types.Object, qf types.Qualifier, declPos token.Pos, file
 		// specifically, we show the receiver name,
 		// and replace the period in (T).f by a space (#62190).
 
-		sig := obj.Type().(*types.Signature)
+		sig := obj.Signature()
 
 		var buf bytes.Buffer
 		buf.WriteString("func ")
@@ -1236,7 +1236,7 @@ func StdSymbolOf(obj types.Object) *stdlib.Symbol {
 
 	// Handle Method.
 	if fn, _ := obj.(*types.Func); fn != nil {
-		isPtr, named := typesinternal.ReceiverNamed(fn.Type().(*types.Signature).Recv())
+		isPtr, named := typesinternal.ReceiverNamed(fn.Signature().Recv())
 		if isPackageLevel(named.Obj()) {
 			for _, s := range symbols {
 				if s.Kind != stdlib.Method {

gopls/internal/golang/implementation.go

@@ -126,7 +126,7 @@ func implementations(ctx context.Context, snapshot *cache.Snapshot, fh file.Hand
 			return obj.Type(), ""
 		case *types.Func:
 			// For methods, use the receiver type, which may be anonymous.
-			if recv := obj.Type().(*types.Signature).Recv(); recv != nil {
+			if recv := obj.Signature().Recv(); recv != nil {
 				return recv.Type(), obj.Id()
 			}
 		}
@@ -317,7 +317,7 @@ func implementsObj(ctx context.Context, snapshot *cache.Snapshot, uri protocol.D
 	case *types.TypeName:
 		// ok
 	case *types.Func:
-		if obj.Type().(*types.Signature).Recv() == nil {
+		if obj.Signature().Recv() == nil {
 			return nil, nil, fmt.Errorf("%s is a function, not a method", id.Name)
 		}
 	case nil:

gopls/internal/golang/pkgdoc.go

@@ -120,7 +120,7 @@ func DocFragment(pkg *cache.Package, pgf *parsego.File, start, end token.Pos) (p
 	if !sym.Exported() {
 		// Unexported method of exported type?
 		if fn, ok := sym.(*types.Func); ok {
-			if recv := fn.Type().(*types.Signature).Recv(); recv != nil {
+			if recv := fn.Signature().Recv(); recv != nil {
 				_, named := typesinternal.ReceiverNamed(recv)
 				if named != nil && named.Obj().Exported() {
 					sym = named.Obj()
@@ -147,7 +147,7 @@ func DocFragment(pkg *cache.Package, pgf *parsego.File, start, end token.Pos) (p
 	// Inv: sym is field or method, or local.
 	switch sym := sym.(type) {
 	case *types.Func: // => method
-		sig := sym.Type().(*types.Signature)
+		sig := sym.Signature()
 		isPtr, named := typesinternal.ReceiverNamed(sig.Recv())
 		if named != nil {
 			if !named.Obj().Exported() {
@@ -469,7 +469,7 @@ window.addEventListener('load', function() {
 		label := obj.Name() // for a type
 		if fn, ok := obj.(*types.Func); ok {
 			var buf strings.Builder
-			sig := fn.Type().(*types.Signature)
+			sig := fn.Signature()
 			if sig.Recv() != nil {
 				fmt.Fprintf(&buf, "(%s) ", sig.Recv().Name())
 				fragment = recvType + "." + fn.Name()
@@ -551,7 +551,7 @@ window.addEventListener('load', function() {
 
 				// method of package-level named type?
 				if fn, ok := obj.(*types.Func); ok {
-					sig := fn.Type().(*types.Signature)
+					sig := fn.Signature()
 					if sig.Recv() != nil {
 						_, named := typesinternal.ReceiverNamed(sig.Recv())
 						if named != nil {
@@ -648,7 +648,7 @@ window.addEventListener('load', function() {
 	fnString := func(fn *types.Func) string {
 		pkgRelative := typesinternal.NameRelativeTo(pkg.Types())
 
-		sig := fn.Type().(*types.Signature)
+		sig := fn.Signature()
 
 		// Emit "func (recv T) F".
 		var buf bytes.Buffer

gopls/internal/golang/references.go

@@ -615,7 +615,7 @@ func localReferences(pkg *cache.Package, targets map[types.Object]bool, correspo
 // comparisons for obj, if it is a method, or nil otherwise.
 func effectiveReceiver(obj types.Object) types.Type {
 	if fn, ok := obj.(*types.Func); ok {
-		if recv := fn.Type().(*types.Signature).Recv(); recv != nil {
+		if recv := fn.Signature().Recv(); recv != nil {
 			return methodsets.EnsurePointer(recv.Type())
 		}
 	}

gopls/internal/golang/rename.go

@@ -426,7 +426,7 @@ func renameOrdinary(ctx context.Context, snapshot *cache.Snapshot, f file.Handle
 		// contain a reference (xrefs) to the target field.
 
 	case *types.Func:
-		if obj.Type().(*types.Signature).Recv() != nil {
+		if obj.Signature().Recv() != nil {
 			transitive = true // method
 		}
 
@@ -978,7 +978,7 @@ func renameObjects(newName string, pkg *cache.Package, targets ...types.Object)
 	// TODO(adonovan): pull this into the caller.
 	for _, obj := range targets {
 		if obj, ok := obj.(*types.Func); ok {
-			recv := obj.Type().(*types.Signature).Recv()
+			recv := obj.Signature().Recv()
 			if recv != nil && types.IsInterface(recv.Type().Underlying()) {
 				r.changeMethods = true
 				break
@@ -1168,7 +1168,7 @@ func (r *renamer) updateCommentDocLinks() (map[protocol.DocumentURI][]diff.Edit,
 			if !isFunc {
 				continue
 			}
-			recv := obj.Type().(*types.Signature).Recv()
+			recv := obj.Signature().Recv()
 			if recv == nil {
 				continue
 			}

gopls/internal/golang/rename_check.go

@@ -883,7 +883,7 @@ func (r *renamer) satisfy() map[satisfy.Constraint]bool {
 
 // recv returns the method's receiver.
 func recv(meth *types.Func) *types.Var {
-	return meth.Type().(*types.Signature).Recv()
+	return meth.Signature().Recv()
 }
 
 // someUse returns an arbitrary use of obj within info.

gopls/internal/golang/stub.go

@@ -208,7 +208,7 @@ func stubMethodsFixer(ctx context.Context, snapshot *cache.Snapshot, pkg *cache.
 	// Otherwise, use lowercase for the first letter of the object.
 	rn := strings.ToLower(si.Concrete.Obj().Name()[0:1])
 	for i := 0; i < si.Concrete.NumMethods(); i++ {
-		if recv := si.Concrete.Method(i).Type().(*types.Signature).Recv(); recv.Name() != "" {
+		if recv := si.Concrete.Method(i).Signature().Recv(); recv.Name() != "" {
 			rn = recv.Name()
 			break
 		}
@@ -229,7 +229,7 @@ func stubMethodsFixer(ctx context.Context, snapshot *cache.Snapshot, pkg *cache.
 
 	for index := range missing {
 		mrn := rn + " "
-		sig := missing[index].fn.Type().(*types.Signature)
+		sig := missing[index].fn.Signature()
 		if checkRecvName(sig.Params()) || checkRecvName(sig.Results()) {
 			mrn = ""
 		}