2 files changed, 30 insertions, 13 deletions
diff --git a/src/cmd/compile/internal/noder/reader.go b/src/cmd/compile/internal/noder/reader.go
index 9280232fc9..1acc8c7fb6 100644
--- a/src/cmd/compile/internal/noder/reader.go
+++ b/src/cmd/compile/internal/noder/reader.go
@@ -1490,7 +1490,7 @@ func (r *reader) addLocal(name *ir.Name, ctxt ir.Class) {
 	if name.Sym().Name == dictParamName {
 		r.dictParam = name
 	} else {
-		if ctxt == ir.PAUTO {
+		if r.synthetic == nil {
 			r.Sync(pkgbits.SyncAddLocal)
 			if r.p.SyncMarkers() {
 				want := r.Int()
@@ -1498,12 +1498,10 @@ func (r *reader) addLocal(name *ir.Name, ctxt ir.Class) {
 					base.FatalfAt(name.Pos(), "locals table has desynced")
 				}
 			}
+			r.varDictIndex(name)
 		}
 
 		r.locals = append(r.locals, name)
-
-		// TODO(go.dev/issue/54514): Set name.DictIndex for variables of
-		// derived type and enable cmd/link/internal/ld.TestDictIndex.
 	}
 
 	name.SetUsed(true)
@@ -3062,6 +3060,17 @@ func (r *reader) rtype0(pos src.XPos) (typ *types.Type, rtype ir.Node) {
 	return
 }
 
+// varDictIndex populates name.DictIndex if name is a derived type.
+func (r *reader) varDictIndex(name *ir.Name) {
+	if r.Bool() {
+		idx := 1 + r.dict.rtypesOffset() + r.Len()
+		if int(uint16(idx)) != idx {
+			base.FatalfAt(name.Pos(), "DictIndex overflow for %v: %v", name, idx)
+		}
+		name.DictIndex = uint16(idx)
+	}
+}
+
 func (r *reader) itab(pos src.XPos) (typ *types.Type, typRType ir.Node, iface *types.Type, ifaceRType ir.Node, itab ir.Node) {
 	if r.Bool() { // derived types
 		idx := r.Len()
diff --git a/src/cmd/compile/internal/noder/writer.go b/src/cmd/compile/internal/noder/writer.go
index a90aec9fc8..6c2ef033f6 100644
--- a/src/cmd/compile/internal/noder/writer.go
+++ b/src/cmd/compile/internal/noder/writer.go
@@ -1090,20 +1090,19 @@ func (w *writer) funcargs(sig *types2.Signature) {
 
 func (w *writer) funcarg(param *types2.Var, result bool) {
 	if param.Name() != "" || result {
-		w.addLocal(param, true)
+		w.addLocal(param)
 	}
 }
 
 // addLocal records the declaration of a new local variable.
-func (w *writer) addLocal(obj *types2.Var, isParam bool) {
+func (w *writer) addLocal(obj *types2.Var) {
 	idx := len(w.localsIdx)
 
-	if !isParam {
-		w.Sync(pkgbits.SyncAddLocal)
-		if w.p.SyncMarkers() {
-			w.Int(idx)
-		}
+	w.Sync(pkgbits.SyncAddLocal)
+	if w.p.SyncMarkers() {
+		w.Int(idx)
 	}
+	w.varDictIndex(obj)
 
 	if w.localsIdx == nil {
 		w.localsIdx = make(map[*types2.Var]int)
@@ -1295,7 +1294,7 @@ func (w *writer) assign(expr syntax.Expr) {
 
 			// TODO(mdempsky): Minimize locals index size by deferring
 			// this until the variables actually come into scope.
-			w.addLocal(obj, false)
+			w.addLocal(obj)
 			return
 		}
 	}
@@ -1558,7 +1557,7 @@ func (w *writer) switchStmt(stmt *syntax.SwitchStmt) {
 
 			obj := obj.(*types2.Var)
 			w.typ(obj.Type())
-			w.addLocal(obj, false)
+			w.addLocal(obj)
 		}
 
 		w.stmts(clause.Body)
@@ -2177,6 +2176,15 @@ func (w *writer) rtype(typ types2.Type) {
 	}
 }
 
+// varDictIndex writes out information for populating DictIndex for
+// the ir.Name that will represent obj.
+func (w *writer) varDictIndex(obj *types2.Var) {
+	info := w.p.typIdx(obj.Type(), w.dict)
+	if w.Bool(info.derived) {
+		w.Len(w.dict.rtypeIdx(info))
+	}
+}
+
 func isUntyped(typ types2.Type) bool {
 	basic, ok := typ.(*types2.Basic)
 	return ok && basic.Info()&types2.IsUntyped != 0