[cfe] Top level function wildcard parameters are non-binding.

This CL prevents function wildcard parameter collisions and avoids adding function wildcard parameters to scope.

Bug: #55655
Change-Id: I5a8b85ceef15b355f6a36a1d1d19df038980331d
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/371941
Reviewed-by: Johnni Winther <[email protected]>
Reviewed-by: Chloe Stefantsova <[email protected]>
Commit-Queue: Kallen Tu <[email protected]>

Author: kallentu

pkg/front_end/lib/src/fasta/source/outline_builder.dart

@@ -2827,7 +2827,8 @@ class OutlineBuilder extends StackListenerImpl {
       if (formals.length == 2) {
         // The name may be null for generalized function types.
         if (formals[0].name != FormalParameterBuilder.noNameSentinel &&
-            formals[0].name == formals[1].name) {
+            formals[0].name == formals[1].name &&
+            !formals[0].isWildcard) {
           addProblem(
               templateDuplicatedParameterName.withArguments(formals[1].name),
               formals[1].charOffset,
@@ -2843,6 +2844,9 @@ class OutlineBuilder extends StackListenerImpl {
         Map<String, FormalParameterBuilder> seenNames =
             <String, FormalParameterBuilder>{};
         for (FormalParameterBuilder formal in formals) {
+          if (formal.isWildcard) {
+            continue;
+          }
           if (formal.name == FormalParameterBuilder.noNameSentinel) continue;
           if (seenNames.containsKey(formal.name)) {
             addProblem(

pkg/front_end/lib/src/fasta/source/source_function_builder.dart

@@ -208,6 +208,9 @@ abstract class SourceFunctionBuilderImpl extends SourceMemberBuilderImpl
     if (formals == null) return parent;
     Map<String, Builder> local = <String, Builder>{};
     for (FormalParameterBuilder formal in formals!) {
+      if (formal.isWildcard) {
+        continue;
+      }
       if (!isConstructor ||
           !formal.isInitializingFormal && !formal.isSuperInitializingFormal) {
         local[formal.name] = formal;

pkg/front_end/testcases/wildcard_variables/top_level_function_no_collision.dart

@@ -0,0 +1,16 @@
+// Copyright (c) 2024, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+void fn(_, _) {
+  print(_);
+}
+
+void fn2(_, _, _) {
+  print(_);
+}
+
+test() {
+  fn(1, 2);
+  fn2(1, 2, 3);
+}

pkg/front_end/testcases/wildcard_variables/top_level_function_no_collision.dart.strong.expect

@@ -0,0 +1,29 @@
+library;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/wildcard_variables/top_level_function_no_collision.dart:6:9: Error: Undefined name '_'.
+//   print(_);
+//         ^
+//
+// pkg/front_end/testcases/wildcard_variables/top_level_function_no_collision.dart:10:9: Error: Undefined name '_'.
+//   print(_);
+//         ^
+//
+import self as self;
+import "dart:core" as core;
+
+static method fn(wildcard dynamic _, wildcard dynamic _) → void {
+  core::print(invalid-expression "pkg/front_end/testcases/wildcard_variables/top_level_function_no_collision.dart:6:9: Error: Undefined name '_'.
+  print(_);
+        ^");
+}
+static method fn2(wildcard dynamic _, wildcard dynamic _, wildcard dynamic _) → void {
+  core::print(invalid-expression "pkg/front_end/testcases/wildcard_variables/top_level_function_no_collision.dart:10:9: Error: Undefined name '_'.
+  print(_);
+        ^");
+}
+static method test() → dynamic {
+  self::fn(1, 2);
+  self::fn2(1, 2, 3);
+}

pkg/front_end/testcases/wildcard_variables/top_level_function_no_collision.dart.strong.modular.expect

@@ -0,0 +1,29 @@
+library;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/wildcard_variables/top_level_function_no_collision.dart:6:9: Error: Undefined name '_'.
+//   print(_);
+//         ^
+//
+// pkg/front_end/testcases/wildcard_variables/top_level_function_no_collision.dart:10:9: Error: Undefined name '_'.
+//   print(_);
+//         ^
+//
+import self as self;
+import "dart:core" as core;
+
+static method fn(wildcard dynamic _, wildcard dynamic _) → void {
+  core::print(invalid-expression "pkg/front_end/testcases/wildcard_variables/top_level_function_no_collision.dart:6:9: Error: Undefined name '_'.
+  print(_);
+        ^");
+}
+static method fn2(wildcard dynamic _, wildcard dynamic _, wildcard dynamic _) → void {
+  core::print(invalid-expression "pkg/front_end/testcases/wildcard_variables/top_level_function_no_collision.dart:10:9: Error: Undefined name '_'.
+  print(_);
+        ^");
+}
+static method test() → dynamic {
+  self::fn(1, 2);
+  self::fn2(1, 2, 3);
+}

pkg/front_end/testcases/wildcard_variables/top_level_function_no_collision.dart.strong.outline.expect

@@ -0,0 +1,9 @@
+library;
+import self as self;
+
+static method fn(wildcard dynamic _, wildcard dynamic _) → void
+  ;
+static method fn2(wildcard dynamic _, wildcard dynamic _, wildcard dynamic _) → void
+  ;
+static method test() → dynamic
+  ;

pkg/front_end/testcases/wildcard_variables/top_level_function_no_collision.dart.strong.transformed.expect

@@ -0,0 +1,29 @@
+library;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/wildcard_variables/top_level_function_no_collision.dart:6:9: Error: Undefined name '_'.
+//   print(_);
+//         ^
+//
+// pkg/front_end/testcases/wildcard_variables/top_level_function_no_collision.dart:10:9: Error: Undefined name '_'.
+//   print(_);
+//         ^
+//
+import self as self;
+import "dart:core" as core;
+
+static method fn(wildcard dynamic _, wildcard dynamic _) → void {
+  core::print(invalid-expression "pkg/front_end/testcases/wildcard_variables/top_level_function_no_collision.dart:6:9: Error: Undefined name '_'.
+  print(_);
+        ^");
+}
+static method fn2(wildcard dynamic _, wildcard dynamic _, wildcard dynamic _) → void {
+  core::print(invalid-expression "pkg/front_end/testcases/wildcard_variables/top_level_function_no_collision.dart:10:9: Error: Undefined name '_'.
+  print(_);
+        ^");
+}
+static method test() → dynamic {
+  self::fn(1, 2);
+  self::fn2(1, 2, 3);
+}

pkg/front_end/testcases/wildcard_variables/top_level_function_no_collision.dart.textual_outline.expect

@@ -0,0 +1,5 @@
+void fn(_, _) {}
+
+void fn2(_, _, _) {}
+
+test() {}

pkg/front_end/testcases/wildcard_variables/top_level_function_no_collision.dart.textual_outline_modelled.expect

@@ -0,0 +1,5 @@
+test() {}
+
+void fn(_, _) {}
+
+void fn2(_, _, _) {}

tests/language/wildcard_variables/unnamed_optional/unnamed_optional_error_test.dart

@@ -24,7 +24,6 @@ class SubClass extends SuperClass {
   //      ^
   // [analyzer] COMPILE_TIME_ERROR.DUPLICATE_DEFINITION
   // [analyzer] COMPILE_TIME_ERROR.MISSING_DEFAULT_VALUE_FOR_PARAMETER
-  // [cfe] Duplicated parameter name '_'.
   // [cfe] The parameter '_' can't have a value of 'null' because of its type 'int', but the implicit default value is 'null'.
   // [cfe] Type 'int' of the optional super-initializer parameter '_' doesn't allow 'null', but the parameter doesn't have a default value, and the default value can't be copied from the corresponding parameter of the super constructor.
   ]);
@@ -41,7 +40,6 @@ class TypedSubClass extends SuperClass {
     //        ^
     // [analyzer] COMPILE_TIME_ERROR.DUPLICATE_DEFINITION
     // [analyzer] COMPILE_TIME_ERROR.MISSING_DEFAULT_VALUE_FOR_PARAMETER
-    // [cfe] Duplicated parameter name '_'.
     // [cfe] The parameter '_' can't have a value of 'null' because of its type 'int', but the implicit default value is 'null'.
     // [cfe] Type 'int' of the optional super-initializer parameter '_' doesn't allow 'null', but the parameter doesn't have a default value, and the default value can't be copied from the corresponding parameter of the super constructor.
   ]) : super.nullable();