diff --git a/cmd/vet/shadow.go b/cmd/vet/shadow.go
index 34e5db90..fa680a03 100644
--- a/cmd/vet/shadow.go
+++ b/cmd/vet/shadow.go
@@ -213,7 +213,7 @@ func checkShadowing(f *File, ident *ast.Ident) {
 	}
 	// obj.Parent.Parent is the surrounding scope. If we can find another declaration
 	// starting from there, we have a shadowed identifier.
-	_, shadowed := obj.Parent().Parent().LookupParent(obj.Name())
+	_, shadowed := obj.Parent().Parent().LookupParent(obj.Name(), obj.Pos())
 	if shadowed == nil {
 		return
 	}
diff --git a/cmd/vet/unused.go b/cmd/vet/unused.go
index db988fe1..b9d7b65f 100644
--- a/cmd/vet/unused.go
+++ b/cmd/vet/unused.go
@@ -32,7 +32,7 @@ func init() {
 }
 
 // func() string
-var sigNoArgsStringResult = types.NewSignature(nil, nil, nil,
+var sigNoArgsStringResult = types.NewSignature(nil, nil,
 	types.NewTuple(types.NewVar(token.NoPos, nil, "", types.Typ[types.String])),
 	false)