Merge pull request github#17709 from owen-mc/go/extractor/objecttypes…

…-consistency-generics

Go: extractor/objecttypes consistency generics

go/extractor/extractor.go

@@ -518,6 +518,7 @@ func extractMethod(tw *trap.Writer, meth *types.Func) trap.Label {
 // For more information on objects, see:
 // https://github.com/golang/example/blob/master/gotypes/README.md#objects
 func extractObject(tw *trap.Writer, obj types.Object, lbl trap.Label) {
+	checkObjectNotSpecialized(obj)
 	name := obj.Name()
 	isBuiltin := obj.Parent() == types.Universe
 	var kind int
@@ -1637,7 +1638,7 @@ func extractType(tw *trap.Writer, tp types.Type) trap.Label {
 				// Note that methods coming from embedded interfaces can be
 				// accessed through `Method(i)`, so there is no need to
 				// deal with them separately.
-				meth := tp.Method(i)
+				meth := tp.Method(i).Origin()
 
 				// Note that methods do not have a parent scope, so they are
 				// not dealt with by `extractScopes`
@@ -1707,15 +1708,15 @@ func extractType(tw *trap.Writer, tp types.Type) trap.Label {
 			// ensure all methods have labels - note that methods do not have a
 			// parent scope, so they are not dealt with by `extractScopes`
 			for i := 0; i < origintp.NumMethods(); i++ {
-				meth := origintp.Method(i)
+				meth := origintp.Method(i).Origin()
 
 				extractMethod(tw, meth)
 			}
 
 			// associate all methods of underlying interface with this type
 			if underlyingInterface, ok := underlying.(*types.Interface); ok {
 				for i := 0; i < underlyingInterface.NumMethods(); i++ {
-					methlbl := extractMethod(tw, underlyingInterface.Method(i))
+					methlbl := extractMethod(tw, underlyingInterface.Method(i).Origin())
 					dbscheme.MethodHostsTable.Emit(tw, methlbl, lbl)
 				}
 			}
@@ -1787,7 +1788,7 @@ func getTypeLabel(tw *trap.Writer, tp types.Type) (trap.Label, bool) {
 		case *types.Interface:
 			var b strings.Builder
 			for i := 0; i < tp.NumMethods(); i++ {
-				meth := tp.Method(i)
+				meth := tp.Method(i).Origin()
 				methLbl := extractType(tw, meth.Type())
 				if i > 0 {
 					b.WriteString(",")
@@ -2143,3 +2144,20 @@ func skipExtractingValueForLeftOperand(tw *trap.Writer, be *ast.BinaryExpr) bool
 	}
 	return true
 }
+
+// checkObjectNotSpecialized exits the program if `obj` is specialized. Note
+// that specialization is only possible for function objects and variable
+// objects.
+func checkObjectNotSpecialized(obj types.Object) {
+	if funcObj, ok := obj.(*types.Func); ok && funcObj != funcObj.Origin() {
+		log.Fatalf("Encountered unexpected specialization %s of generic function object %s", funcObj.FullName(), funcObj.Origin().FullName())
+	}
+	if varObj, ok := obj.(*types.Var); ok && varObj != varObj.Origin() {
+		log.Fatalf("Encountered unexpected specialization %s of generic variable object %s", varObj.String(), varObj.Origin().String())
+	}
+	if typeNameObj, ok := obj.(*types.TypeName); ok {
+		if namedType, ok := typeNameObj.Type().(*types.Named); ok && namedType != namedType.Origin() {
+			log.Fatalf("Encountered type object for specialization %s of named type %s", namedType.String(), namedType.Origin().String())
+		}
+	}
+}