Don't define parameters when visiting a function-typed formal parameter.

pkg/analyzer/lib/src/generated/resolver.dart

Index: pkg/analyzer/lib/src/generated/resolver.dart
diff --git a/pkg/analyzer/lib/src/generated/resolver.dart b/pkg/analyzer/lib/src/generated/resolver.dart
index 475c5b09df4550e1dedfc45f3b02fbcf5b5f5a07..fb22d618878d10acde34b4840ee13a9bdbc106dc 100644
--- a/pkg/analyzer/lib/src/generated/resolver.dart
+++ b/pkg/analyzer/lib/src/generated/resolver.dart
@@ -12189,8 +12189,11 @@ abstract class ScopedVisitor extends UnifyingAstVisitor<Object> {
   Object visitFormalParameterList(FormalParameterList node) {
     super.visitFormalParameterList(node);
     // We finished resolving function signature, now include formal parameters
-    // scope.
-    if (_nameScope is FunctionScope) {
+    // scope.  Note: we must not do this if the parent is a
+    // FunctionTypedFormalParameter, because in that case we aren't finished
+    // resolving the full function signature, just a part of it.
+    if (_nameScope is FunctionScope &&
+        node.parent is! FunctionTypedFormalParameter) {
       (_nameScope as FunctionScope).defineParameters();
     }
     if (_nameScope is FunctionTypeScope) {