[CFE] Expression compilation inside inner function in extension/extension type

The VM sends the name of the inner function which we can't look up so we
need to get it from the offset.
A future CL should probably stop passing the method name at all.

There are still snafus possible here, although seemingly unrelated
(see #61502).

Change-Id: Ife3da622ca5d2f95be5024c8bbcfb700503f256d
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/449540
Reviewed-by: Johnni Winther <[email protected]>
Commit-Queue: Jens Johansen <[email protected]>

Author: jensjoha

pkg/front_end/lib/src/api_prototype/lowering_predicates.dart

@@ -917,12 +917,37 @@ const String unnamedExtensionSentinel = '<unnamed extension>';
 ///   extractQualifiedNameFromExtensionMethodName('_extension#3|set#bar'),
 ///   '<unnamed extension>.bar')
 ///
-String? extractQualifiedNameFromExtensionMethodName(String? methodName) {
+///  DartDocTest(
+///    extractQualifiedNameFromExtensionMethodName(
+///      '_extension#1|bar',
+///      keepUnnamedExtensionNamePrefix: true,
+///    ),
+///    '_extension#1.bar',
+///  )
+///  DartDocTest(
+///    extractQualifiedNameFromExtensionMethodName(
+///      '_extension#2|get#bar',
+///      keepUnnamedExtensionNamePrefix: true,
+///    ),
+///    '_extension#2.bar',
+///  )
+///  DartDocTest(
+///    extractQualifiedNameFromExtensionMethodName(
+///      '_extension#3|set#bar',
+///      keepUnnamedExtensionNamePrefix: true,
+///    ),
+///    '_extension#3.bar',
+///  )
+String? extractQualifiedNameFromExtensionMethodName(
+  String? methodName, {
+  bool keepUnnamedExtensionNamePrefix = false,
+}) {
   if (methodName == null) return null;
   int delimiterIndex = methodName.indexOf(NameScheme.extensionNameDelimiter);
   if (delimiterIndex == -1) return null;
   String extensionName = methodName.substring(0, delimiterIndex);
-  if (extensionName.startsWith(NameScheme.unnamedExtensionNamePrefix)) {
+  if (extensionName.startsWith(NameScheme.unnamedExtensionNamePrefix) &&
+      !keepUnnamedExtensionNamePrefix) {
     extensionName = unnamedExtensionSentinel;
   }
   String memberName = methodName.substring(

pkg/front_end/lib/src/base/incremental_compiler.dart

@@ -73,7 +73,11 @@ import '../api_prototype/incremental_kernel_generator.dart'
         IncrementalKernelGenerator,
         isLegalIdentifier;
 import '../api_prototype/lowering_predicates.dart'
-    show isExtensionThisName, syntheticThisName, hasUnnamedExtensionNamePrefix;
+    show
+        isExtensionThisName,
+        syntheticThisName,
+        hasUnnamedExtensionNamePrefix,
+        extractQualifiedNameFromExtensionMethodName;
 import '../api_prototype/memory_file_system.dart' show MemoryFileSystem;
 import '../builder/builder.dart' show Builder;
 import '../builder/compilation_unit.dart'
@@ -1835,6 +1839,7 @@ class IncrementalCompiler implements IncrementalKernelGenerator {
       }
       LibraryBuilder libraryBuilder = compilationUnit.libraryBuilder;
       List<VariableDeclarationImpl> extraKnownVariables = [];
+      String? usedMethodName = methodName;
       if (scriptUri != null && offset != TreeNode.noOffset) {
         Uri? scriptUriAsUri = Uri.tryParse(scriptUri);
         if (scriptUriAsUri != null) {
@@ -1866,6 +1871,15 @@ class IncrementalCompiler implements IncrementalKernelGenerator {
             offset,
           );
 
+          if (foundScope.member != null &&
+              (foundScope.member!.isExtensionMember ||
+                  foundScope.member!.isExtensionTypeMember)) {
+            usedMethodName = extractQualifiedNameFromExtensionMethodName(
+              foundScope.member!.name.text,
+              keepUnnamedExtensionNamePrefix: true,
+            );
+          }
+
           Map<TypeParameter, TypeParameterType> substitutionMap = {};
           Map<String, TypeParameter> typeDefinitionNamesMap = {};
           for (TypeParameter typeDefinition in typeDefinitions) {
@@ -1959,11 +1973,11 @@ class IncrementalCompiler implements IncrementalKernelGenerator {
       Extension? extension;
       ExtensionTypeDeclaration? extensionType;
       String? extensionName;
-      if (methodName != null) {
-        int indexOfDot = methodName.indexOf(".");
+      if (usedMethodName != null) {
+        int indexOfDot = usedMethodName.indexOf(".");
         if (indexOfDot >= 0) {
-          String beforeDot = methodName.substring(0, indexOfDot);
-          String afterDot = methodName.substring(indexOfDot + 1);
+          String beforeDot = usedMethodName.substring(0, indexOfDot);
+          String afterDot = usedMethodName.substring(indexOfDot + 1);
           Builder? builder = libraryBuilder.libraryNameSpace
               .lookup(beforeDot)
               ?.getable;

pkg/front_end/test/dartdoc_test_test.dart

@@ -380,7 +380,7 @@ void testTestExtraction() {
     ],
   );
 
-  // Two valid tests. Four invalid ones.
+  // Two valid tests. Five invalid ones.
   expect(
     extractTests("""
 // DartDocTest(1+1, 2)
@@ -389,6 +389,7 @@ void testTestExtraction() {
 // DartDocTest(2+40, 42]
 // DartDocTest(2+40, 42)
 // DartDocTest(2+40, 42+)
+// DartDocTest(2+40, 42, 42)
 """),
     <impl.Test>[
       new impl.ExpectTest("1+1", "2", "darttest:/foo.dart:1:16"),
@@ -425,6 +426,13 @@ darttest:/foo.dart:6:25: Expected an identifier, but got ')'.
         148,
         "darttest:/foo.dart:6:25",
       ),
+      new impl.TestParseError(
+        """darttest:/foo.dart:7:24: Expected ')' before this.
+// DartDocTest(2+40, 42, 42)
+                       ^""",
+        173,
+        "darttest:/foo.dart:7:24",
+      ),
     ],
   );
 
@@ -519,6 +527,25 @@ darttest:/foo.dart:6:25: Expected an identifier, but got ')'.
       new impl.ThrowsTest("2~/0", "darttest:/foo.dart:7:26"),
     ],
   );
+
+  // Expect with trailing comma.
+  expect(
+    extractTests("""
+    // not a test comment
+    void foo_bar_long_name() {}
+
+    // DartDocTestThrows(1~/0,)
+    // DartDocTest(1+1, 2,)
+    // DartDocTest(2+2, 4, )
+    // DartDocTestThrows(2~/0, )"""),
+    <impl.Test>[
+      // For now the order is expect tests first.
+      new impl.ExpectTest("1+1", "2", "darttest:/foo.dart:5:20"),
+      new impl.ExpectTest("2+2", "4", "darttest:/foo.dart:6:20"),
+      new impl.ThrowsTest("1~/0", "darttest:/foo.dart:4:26"),
+      new impl.ThrowsTest("2~/0", "darttest:/foo.dart:7:26"),
+    ],
+  );
 }
 
 void testCommentExtraction() {

pkg/front_end/testcases/expression/extension_type_with_inner_function_declaration.expression.yaml

@@ -0,0 +1,44 @@
+# Copyright (c) 2025, 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.
+
+# Definition, offset, method etc extracted by starting the VM with
+# `-DDFE_VERBOSE=true`, e.g.
+# ```
+# out/ReleaseX64/dart -DDFE_VERBOSE=true --enable-vm-service \
+# --disable-service-auth-codes --pause_isolates_on_start inputFile.dart
+# ```
+# and then issuing the expression compilation.
+#
+# Paused inside a function declaration inside an extension type.
+
+sources: |
+  import 'dart:developer';
+
+  extension type Foo(int value) {
+    void foo() {
+      void bar() {
+        debugger();
+        if (value == 42) {
+          print("It's 42!");
+        }
+      }
+      bar();
+    }
+  }
+
+  void main(List<String> args) {
+    Foo foo = new Foo(args.length);
+    foo.foo();
+  }
+
+definitions: ["#this"]
+definition_types: ["dart:core", "_Smi", "1", "0"]
+type_definitions: []
+type_bounds: []
+type_defaults: []
+method: "bar"
+static: true
+offset: 96
+scriptUri: main.dart
+expression: "value"

pkg/front_end/testcases/expression/extension_type_with_inner_function_declaration.expression.yaml.expect

@@ -0,0 +1,4 @@
+Errors: {
+}
+method /* from org-dartlang-debug:synthetic_debug_expression */ debugExpr(lowered #lib1::Foo% /* erasure=dart.core::int, declared=! */ #this) → dynamic
+  return #this as{Unchecked} dart.core::int;

pkg/front_end/testcases/expression/extension_type_with_inner_function_expression.expression.yaml

@@ -0,0 +1,43 @@
+# Copyright (c) 2025, 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.
+
+# Definition, offset, method etc extracted by starting the VM with
+# `-DDFE_VERBOSE=true`, e.g.
+# ```
+# out/ReleaseX64/dart -DDFE_VERBOSE=true --enable-vm-service \
+# --disable-service-auth-codes --pause_isolates_on_start inputFile.dart
+# ```
+# and then issuing the expression compilation.
+#
+# Paused inside a function expression inside an extension type.
+
+sources: |
+  import 'dart:developer';
+
+  extension type Foo(int value) {
+    void foo() {
+      () {
+        debugger();
+        if (value == 42) {
+          print("It's 42!");
+        }
+      }();
+    }
+  }
+
+  void main(List<String> args) {
+    Foo foo = new Foo(args.length);
+    foo.foo();
+  }
+
+definitions: ["#this"]
+definition_types: ["dart:core", "_Smi", "1", "0"]
+type_definitions: []
+type_bounds: []
+type_defaults: []
+method: "<anonymous closure>"
+static: true
+offset: 88
+scriptUri: main.dart
+expression: "value"

pkg/front_end/testcases/expression/extension_type_with_inner_function_expression.expression.yaml.expect

@@ -0,0 +1,4 @@
+Errors: {
+}
+method /* from org-dartlang-debug:synthetic_debug_expression */ debugExpr(lowered #lib1::Foo% /* erasure=dart.core::int, declared=! */ #this) → dynamic
+  return #this as{Unchecked} dart.core::int;

pkg/front_end/testcases/expression/extension_with_inner_function_declaration.expression.yaml

@@ -0,0 +1,43 @@
+# Copyright (c) 2025, 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.
+
+# Definition, offset, method etc extracted by starting the VM with
+# `-DDFE_VERBOSE=true`, e.g.
+# ```
+# out/ReleaseX64/dart -DDFE_VERBOSE=true --enable-vm-service \
+# --disable-service-auth-codes --pause_isolates_on_start inputFile.dart
+# ```
+# and then issuing the expression compilation.
+#
+# Paused inside a function declaration inside an extension.
+
+sources: |
+  import 'dart:developer';
+
+  extension on int {
+    void foo() {
+      void bar() {
+        debugger();
+        if (this == 42) {
+          print("It's 42!");
+        }
+      }
+      bar();
+    }
+  }
+
+  void main(List<String> args) {
+    args.length.foo();
+  }
+
+definitions: ["#this"]
+definition_types: ["dart:core", "_Smi", "1", "0"]
+type_definitions: []
+type_bounds: []
+type_defaults: []
+method: "bar"
+static: true
+offset: 83
+scriptUri: main.dart
+expression: "this"

pkg/front_end/testcases/expression/extension_with_inner_function_declaration.expression.yaml.expect

@@ -0,0 +1,4 @@
+Errors: {
+}
+method /* from org-dartlang-debug:synthetic_debug_expression */ debugExpr(lowered dart.core::_Smi #this) → dynamic
+  return #this;

pkg/front_end/testcases/expression/extension_with_inner_function_expression.expression.yaml

@@ -0,0 +1,42 @@
+# Copyright (c) 2025, 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.
+
+# Definition, offset, method etc extracted by starting the VM with
+# `-DDFE_VERBOSE=true`, e.g.
+# ```
+# out/ReleaseX64/dart -DDFE_VERBOSE=true --enable-vm-service \
+# --disable-service-auth-codes --pause_isolates_on_start inputFile.dart
+# ```
+# and then issuing the expression compilation.
+#
+# Paused inside a function expression inside an extension.
+
+sources: |
+  import 'dart:developer';
+
+  extension on int {
+    void foo() {
+      () {
+        debugger();
+        if (this == 42) {
+          print("It's 42!");
+        }
+      }();
+    }
+  }
+
+  void main(List<String> args) {
+    args.length.foo();
+  }
+
+definitions: ["#this"]
+definition_types: ["dart:core", "_Smi", "1", "0"]
+type_definitions: []
+type_bounds: []
+type_defaults: []
+method: "<anonymous closure>"
+static: true
+offset: 75
+scriptUri: main.dart
+expression: "this"