[CFE] Expression compilation: Use static type for extension types

This - combiend with sending the scriptUri and offset - allows us to
expression evaluate stuff on extension types.

Change-Id: I0db6c1f52ad3db4ce1a1a2a721e8f3e70033f9ec
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/339900
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Commit-Queue: Jens Johansen <jensj@google.com>

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

@@ -25,6 +25,8 @@ import 'package:kernel/canonical_name.dart'
     show CanonicalNameError, CanonicalNameSdkError;
 import 'package:kernel/class_hierarchy.dart'
     show ClassHierarchy, ClosedWorldClassHierarchy;
+import 'package:kernel/dart_scope_calculator.dart'
+    show DartScope, DartScopeBuilder2;
 import 'package:kernel/kernel.dart'
     show
         Class,
@@ -32,12 +34,14 @@ import 'package:kernel/kernel.dart'
         DartType,
         Expression,
         Extension,
+        ExtensionType,
         FunctionNode,
         Library,
         LibraryDependency,
         LibraryPart,
         Name,
         NamedNode,
+        Node,
         NonNullableByDefaultCompiledMode,
         Procedure,
         ProcedureKind,
@@ -47,7 +51,9 @@ import 'package:kernel/kernel.dart'
         Supertype,
         TreeNode,
         TypeParameter,
-        VariableDeclaration;
+        VariableDeclaration,
+        VisitorDefault,
+        VisitorVoidMixin;
 import 'package:kernel/kernel.dart' as kernel show Combinator;
 import 'package:kernel/target/changed_structure_notifier.dart'
     show ChangedStructureNotifier;
@@ -1789,22 +1795,52 @@ class IncrementalCompiler implements IncrementalKernelGenerator {
   @override
   Future<Procedure?> compileExpression(
     String expression,
-    Map<String, DartType> definitions,
+    Map<String, DartType> inputDefinitions,
     List<TypeParameter> typeDefinitions,
     String syntheticProcedureName,
     Uri libraryUri, {
     String? className,
     String? methodName,
-    int offset = -1,
+    int offset = TreeNode.noOffset,
     String? scriptUri,
     bool isStatic = false,
   }) async {
     IncrementalKernelTarget? lastGoodKernelTarget = this._lastGoodKernelTarget;
     assert(_dillLoadedData != null && lastGoodKernelTarget != null);
+    Map<String, DartType> usedDefinitions =
+        new Map<String, DartType>.of(inputDefinitions);
 
     return await context.runInContext((_) async {
       LibraryBuilder libraryBuilder =
           lastGoodKernelTarget!.loader.readAsEntryPoint(libraryUri);
+
+      if (scriptUri != null && offset != TreeNode.noOffset) {
+        Uri? scriptUriAsUri = Uri.tryParse(scriptUri);
+        if (scriptUriAsUri != null) {
+          Library library = libraryBuilder.library;
+          Class? cls;
+          if (className != null) {
+            for (Class c in library.classes) {
+              if (c.name == className) {
+                cls = c;
+                break;
+              }
+            }
+          }
+          DartScope foundScope = DartScopeBuilder2.findScopeFromOffsetAndClass(
+              library, scriptUriAsUri, cls, offset);
+          // For now, if any definition is (or contains) an Extension Type,
+          // we'll overwrite the given (runtime?) definitions so we know about
+          // the extension type.
+          for (MapEntry<String, DartType> def
+              in foundScope.definitions.entries) {
+            if (_ExtensionTypeFinder.isOrContainsExtensionType(def.value)) {
+              usedDefinitions[def.key] = def.value;
+            }
+          }
+        }
+      }
+
       _ticker.logMs("Loaded library $libraryUri");
 
       Class? cls;
@@ -1854,7 +1890,7 @@ class IncrementalCompiler implements IncrementalKernelGenerator {
         }
       }
       int index = 0;
-      for (String name in definitions.keys) {
+      for (String name in usedDefinitions.keys) {
         index++;
         if (!(isLegalIdentifier(name) ||
             (extension != null &&
@@ -1961,9 +1997,9 @@ class IncrementalCompiler implements IncrementalKernelGenerator {
       // https://github.com/dart-lang/sdk/issues/44158
       FunctionNode parameters = new FunctionNode(null,
           typeParameters: typeDefinitions,
-          positionalParameters: definitions.keys
-              .map<VariableDeclaration>((name) =>
-                  new VariableDeclarationImpl(name, type: definitions[name])
+          positionalParameters: usedDefinitions.entries
+              .map<VariableDeclaration>((MapEntry<String, DartType> def) =>
+                  new VariableDeclarationImpl(def.key, type: def.value)
                     ..fileOffset = cls?.fileOffset ??
                         extension?.fileOffset ??
                         libraryBuilder.library.fileOffset)
@@ -2219,6 +2255,28 @@ class IncrementalCompiler implements IncrementalKernelGenerator {
   }
 }
 
+class _ExtensionTypeFinder extends VisitorDefault<void> with VisitorVoidMixin {
+  static bool isOrContainsExtensionType(DartType type) {
+    if (type is ExtensionType) return true;
+    _ExtensionTypeFinder finder = new _ExtensionTypeFinder();
+    type.accept(finder);
+    return finder._foundExtensionType;
+  }
+
+  @override
+  void visitExtensionType(ExtensionType node) {
+    _foundExtensionType = true;
+  }
+
+  @override
+  void defaultNode(Node node) {
+    if (_foundExtensionType) return;
+    node.visitChildren(this);
+  }
+
+  bool _foundExtensionType = false;
+}
+
 /// Translate a parts "partUri" to an actual uri with handling of invalid uris.
 ///
 /// ```

pkg/front_end/test/fasta/expression_suite.dart

@@ -40,6 +40,7 @@ import "package:kernel/ast.dart"
         Library,
         Member,
         Procedure,
+        TreeNode,
         TypeParameter;
 import 'package:kernel/target/targets.dart' show TargetFlags;
 import 'package:kernel/text/ast_to_text.dart' show Printer;
@@ -152,6 +153,10 @@ class TestCase {
 
   final String? methodName;
 
+  final int? offset;
+
+  final String? scriptUri;
+
   String expression;
 
   List<CompilationResult> results = [];
@@ -169,6 +174,8 @@ class TestCase {
       this.library,
       this.className,
       this.methodName,
+      this.offset,
+      this.scriptUri,
       this.expression);
 
   @override
@@ -266,6 +273,8 @@ class ReadTest extends Step<TestDescription, List<TestCase>, Context> {
     Uri? library;
     String? className;
     String? methodName;
+    int? offset;
+    String? scriptUri;
     String? expression;
 
     dynamic maps = loadYamlNode(contents, sourceUrl: uri);
@@ -310,6 +319,11 @@ class ReadTest extends Step<TestDescription, List<TestCase>, Context> {
           isStaticMethod = value;
         } else if (key == "expression") {
           expression = value;
+        } else if (key == "offset") {
+          offset = value;
+        } else if (key == "scriptUri") {
+          Uri uri = entryPoint.resolveUri(Uri.parse(value as String));
+          scriptUri = uri.toString();
         } else {
           throw new UnsupportedError("Unknown key: ${key}");
         }
@@ -332,6 +346,8 @@ class ReadTest extends Step<TestDescription, List<TestCase>, Context> {
           library,
           className,
           methodName,
+          offset,
+          scriptUri,
           expression);
       tests.add(test);
     }
@@ -386,6 +402,8 @@ class CompileExpression extends Step<List<TestCase>, List<TestCase>, Context> {
       className: test.className,
       methodName: test.methodName,
       isStatic: test.isStaticMethod,
+      scriptUri: test.scriptUri,
+      offset: test.offset ?? TreeNode.noOffset,
     );
     List<DiagnosticMessage> errors = context.takeErrors();
     test.results.add(new CompilationResult(compiledProcedure, errors));

pkg/front_end/testcases/expression/extension_type_01.expression.yaml

@@ -0,0 +1,36 @@
+# Copyright (c) 2023, 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.
+
+sources: |
+  //@dart=3.3
+
+  void main() {
+    Foo f = new Foo(42);
+    print(f);
+    print(f.value);
+    f.printValue();
+    f.printThis();
+  }
+
+  extension type Foo(int value) {
+    void printValue() {
+      print("This foos value is '$value'");
+    }
+    void printThis() {
+      print("This foos this value is '$this'");
+    }
+  }
+
+definitions: ["f"]
+# int
+definition_types: ["dart:core", "int", "1", "0"]
+type_definitions: []
+type_bounds: []
+type_defaults: []
+method: "main"
+static: true
+offset: 64 # at the start of the 'print(f.value);' line.
+scriptUri: main.dart
+expression: |
+  f.value

pkg/front_end/testcases/expression/extension_type_01.expression.yaml.expect

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

pkg/front_end/testcases/expression/extension_type_02.expression.yaml

@@ -0,0 +1,51 @@
+# Copyright (c) 2023, 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.
+
+sources:
+  foo.dart: |
+    //@dart=3.3
+    part    'bar.dart';
+
+    void foo() {
+      Foo x = new Foo(42);
+      print(x);
+      print(x.value);
+      x.printFoo();
+    }
+
+    extension type Foo(int value) {
+      void printFoo() {
+        print("This foos value is '$value'");
+      }
+    }
+  bar.dart: |
+    //@dart=3.3
+    part of 'foo.dart';
+
+    void bar() {
+      Bar x = new Bar('');
+      print(x);
+      print(x.value);
+      x.printBar();
+    }
+
+    extension type Bar(String value) {
+      void printBar() {
+        print("This bars value is '$value'");
+      }
+    }
+
+definitions: ["x"]
+# String
+definition_types: ["dart:core", "String", "1", "0"]
+type_definitions: []
+type_bounds: []
+type_defaults: []
+entry_point: "foo.dart" # the main library
+method: "main"
+static: true
+offset: 83 # at the start of the 'print(x.value);' line. In both files!
+scriptUri: bar.dart
+expression: |
+  x.printBar()

pkg/front_end/testcases/expression/extension_type_02.expression.yaml.expect

@@ -0,0 +1,4 @@
+Errors: {
+}
+static method /* from org-dartlang-debug:synthetic_debug_expression */ debugExpr(#lib1::Bar /* = dart.core::String */ x) → dynamic
+  return #lib1::Bar|printBar(x);

pkg/front_end/testcases/expression/extension_type_02_prime.expression.yaml

@@ -0,0 +1,51 @@
+# Copyright (c) 2023, 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.
+
+sources:
+  foo.dart: |
+    //@dart=3.3
+    part    'bar.dart';
+
+    void foo() {
+      Foo x = new Foo(42);
+      print(x);
+      print(x.value);
+      x.printFoo();
+    }
+
+    extension type Foo(int value) {
+      void printFoo() {
+        print("This foos value is '$value'");
+      }
+    }
+  bar.dart: |
+    //@dart=3.3
+    part of 'foo.dart';
+
+    void bar() {
+      Bar x = new Bar('');
+      print(x);
+      print(x.value);
+      x.printBar();
+    }
+
+    extension type Bar(String value) {
+      void printBar() {
+        print("This bars value is '$value'");
+      }
+    }
+
+definitions: ["x"]
+# int
+definition_types: ["dart:core", "int", "1", "0"]
+type_definitions: []
+type_bounds: []
+type_defaults: []
+entry_point: "foo.dart" # the main library
+method: "main"
+static: true
+offset: 83 # at the start of the 'print(x.value);' line. In both files!
+scriptUri: foo.dart
+expression: |
+  x.printFoo()

pkg/front_end/testcases/expression/extension_type_02_prime.expression.yaml.expect

@@ -0,0 +1,4 @@
+Errors: {
+}
+static method /* from org-dartlang-debug:synthetic_debug_expression */ debugExpr(#lib1::Foo /* = dart.core::int */ x) → dynamic
+  return #lib1::Foo|printFoo(x);

pkg/front_end/testcases/expression/extension_type_03.expression.yaml

@@ -0,0 +1,31 @@
+# Copyright (c) 2023, 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.
+
+sources: |
+  //@dart=3.3
+
+  void main() {
+    Foo f = new Foo(42);
+    List<Foo> foos = [f];
+    foos.first.printValue();
+  }
+
+  extension type Foo(int value) {
+    void printValue() {
+      print("This foos value is '$value'");
+    }
+  }
+
+definitions: ["f", "foos"]
+# int, List<int>
+definition_types: ["dart:core", "int", "1", "0", "dart:core", "List", "1", "1", "dart:core", "int", "1", "0"]
+type_definitions: []
+type_bounds: []
+type_defaults: []
+method: "main"
+static: true
+offset: 76 # at the start of the 'foos.first.printValue();' line.
+scriptUri: main.dart
+expression: |
+  foos.first.value

pkg/front_end/testcases/expression/extension_type_03.expression.yaml.expect

@@ -0,0 +1,4 @@
+Errors: {
+}
+static method /* from org-dartlang-debug:synthetic_debug_expression */ debugExpr(#lib1::Foo /* = dart.core::int */ f, dart.core::List<#lib1::Foo /* = dart.core::int */> foos) → dynamic
+  return foos.{dart.core::Iterable::first}{#lib1::Foo% /* = dart.core::int */} as{Unchecked} dart.core::int;