Include type parameter's index in its label

Author: owen-mc

go/extractor/extractor.go

@@ -1776,7 +1776,8 @@ func getTypeLabel(tw *trap.Writer, tp types.Type) (trap.Label, bool) {
 			lbl = tw.Labeler.GlobalID(fmt.Sprintf("{%s};namedtype", entitylbl))
 		case *types.TypeParam:
 			parentlbl := getTypeParamParentLabel(tw, tp)
-			lbl = tw.Labeler.GlobalID(fmt.Sprintf("{%v},%s;typeparamtype", parentlbl, tp.Obj().Name()))
+			idx := tp.Index()
+			lbl = tw.Labeler.GlobalID(fmt.Sprintf("{%v},%d,%s;typeparamtype", parentlbl, idx, tp.Obj().Name()))
 		case *types.Union:
 			var b strings.Builder
 			for i := 0; i < tp.Len(); i++ {

go/ql/test/library-tests/semmle/go/Function/TypeParamType.expected

@@ -16,9 +16,9 @@ numberOfTypeParameters
 | genericFunctions.go:132:6:132:10 | Graph | 2 |
 | genericFunctions.go:134:6:134:8 | New | 2 |
 | genericFunctions.go:138:29:138:40 | ShortestPath | 2 |
-| genericFunctions.go:150:6:150:36 | multipleAnonymousTypeParamsFunc | 1 |
-| genericFunctions.go:152:6:152:36 | multipleAnonymousTypeParamsType | 1 |
-| genericFunctions.go:154:51:154:51 | f | 1 |
+| genericFunctions.go:150:6:150:36 | multipleAnonymousTypeParamsFunc | 3 |
+| genericFunctions.go:152:6:152:36 | multipleAnonymousTypeParamsType | 3 |
+| genericFunctions.go:154:51:154:51 | f | 3 |
 #select
 | cmp.Compare | 0 | T | Ordered |
 | cmp.Less | 0 | T | Ordered |