[cfe] Build PatternVariableDeclaration in BodyBuilder

Change-Id: Ic55dbc03bf2cf4865275b186266c0f420263d406
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/273744
Commit-Queue: Johnni Winther <[email protected]>
Reviewed-by: Jens Johansen <[email protected]>

Author: johnniwinther

pkg/front_end/lib/src/fasta/kernel/body_builder.dart

@@ -8490,6 +8490,27 @@ class BodyBuilder extends StackListenerImpl
       push(pattern);
     }
   }
+
+  @override
+  void handlePatternVariableDeclarationStatement(
+      Token keyword, Token equals, Token semicolon) {
+    debugEvent('PatternVariableDeclarationStatement');
+    assert(checkState(keyword, [
+      unionOfKinds([
+        ValueKinds.Expression,
+        ValueKinds.Generator,
+        ValueKinds.ProblemBuilder,
+      ]),
+      ValueKinds.Pattern,
+      ValueKinds.AnnotationListOrNull,
+    ]));
+    Expression initializer = popForValue();
+    Pattern pattern = toPattern(pop());
+    // TODO(johnniwinther,cstefantsova): Handle metadata.
+    pop(NullValue.Metadata) as List<Expression>?;
+    push(new PatternVariableDeclaration(pattern, initializer,
+        offset: keyword.charOffset, isFinal: keyword.lexeme == 'final'));
+  }
 }
 
 abstract class EnsureLoaded {

pkg/front_end/lib/src/fasta/kernel/internal_ast.dart

@@ -4742,38 +4742,29 @@ class WildcardPattern extends Pattern {
 class PatternVariableDeclaration extends InternalStatement {
   final Pattern pattern;
   final Expression initializer;
+  final bool isFinal;
 
   PatternVariableDeclaration(this.pattern, this.initializer,
-      {required int offset}) {
+      {required int offset, required this.isFinal}) {
     fileOffset = offset;
   }
 
   @override
   StatementInferenceResult acceptInference(InferenceVisitorImpl visitor) {
-    throw new UnimplementedError("PatternVariableDeclaration.acceptInference");
-  }
-
-  @override
-  R accept<R>(StatementVisitor<R> visitor) {
-    if (visitor is Printer || visitor is Precedence || visitor is Transformer) {
-      // Allow visitors needed for toString and replaceWith.
-      return visitor.defaultStatement(this);
-    }
-    return unsupported(
-        "${runtimeType}.accept on ${visitor.runtimeType}", -1, null);
-  }
-
-  @override
-  R accept1<R, A>(StatementVisitor1<R, A> visitor, A arg) {
-    return unsupported(
-        "${runtimeType}.accept1 on ${visitor.runtimeType}", -1, null);
+    return visitor.visitPatternVariableDeclaration(this);
   }
 
   @override
   void toTextInternal(AstPrinter printer) {
+    if (isFinal) {
+      printer.write('final ');
+    } else {
+      printer.write('var ');
+    }
     pattern.toTextInternal(printer);
     printer.write(" = ");
     printer.writeExpression(initializer);
+    printer.write(';');
   }
 
   @override

pkg/front_end/lib/src/fasta/type_inference/inference_visitor.dart

@@ -8103,6 +8103,12 @@ class InferenceVisitorImpl extends InferenceVisitorBase
     return const StatementInferenceResult();
   }
 
+  StatementInferenceResult visitPatternVariableDeclaration(
+      PatternVariableDeclaration node) {
+    return new StatementInferenceResult.single(
+        new ExpressionStatement(new InvalidExpression('$node')));
+  }
+
   @override
   ExpressionInferenceResult visitVariableGet(
       covariant VariableGetImpl node, DartType typeContext) {

pkg/front_end/test/text_representation/internal_ast_text_representation_test.dart

@@ -129,6 +129,7 @@ void main() {
     _testIfCaseStatement();
     _testPatternSwitchStatement();
     _testSwitchExpression();
+    _testPatternVariableDeclaration();
   });
 }
 
@@ -1312,3 +1313,19 @@ if (0 case 1 when 2) return;''');
       '''
 if (0 case 1 when 2) return 3; else return 4;''');
 }
+
+void _testPatternVariableDeclaration() {
+  testStatement(
+      new PatternVariableDeclaration(
+          new ExpressionPattern(new IntLiteral(0)), new IntLiteral(1),
+          isFinal: false, offset: TreeNode.noOffset),
+      '''
+var 0 = 1;''');
+
+  testStatement(
+      new PatternVariableDeclaration(
+          new ExpressionPattern(new IntLiteral(0)), new IntLiteral(1),
+          isFinal: true, offset: TreeNode.noOffset),
+      '''
+final 0 = 1;''');
+}

pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart

@@ -0,0 +1,7 @@
+// Copyright (c) 2022, 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.
+
+f(x) {
+  late var (_) = x;
+}

pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart.strong.expect

@@ -0,0 +1,38 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:12: Error: Expected an identifier, but got '('.
+// Try inserting an identifier before '('.
+//   late var (_) = x;
+//            ^
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:12: Error: Expected ';' after this.
+//   late var (_) = x;
+//            ^
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:13: Error: Expected ';' after this.
+//   late var (_) = x;
+//             ^
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:13: Error: Undefined name '_'.
+//   late var (_) = x;
+//             ^
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:14: Error: Expected an identifier, but got ')'.
+// Try inserting an identifier before ')'.
+//   late var (_) = x;
+//              ^
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:14: Error: Unexpected token ';'.
+//   late var (_) = x;
+//              ^
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:16: Error: Expected an identifier, but got '='.
+// Try inserting an identifier before '='.
+//   late var (_) = x;
+//                ^
+//
+import self as self;
+
+static method f(dynamic x) → dynamic {}

pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart.strong.transformed.expect

@@ -0,0 +1,38 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:12: Error: Expected an identifier, but got '('.
+// Try inserting an identifier before '('.
+//   late var (_) = x;
+//            ^
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:12: Error: Expected ';' after this.
+//   late var (_) = x;
+//            ^
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:13: Error: Expected ';' after this.
+//   late var (_) = x;
+//             ^
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:13: Error: Undefined name '_'.
+//   late var (_) = x;
+//             ^
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:14: Error: Expected an identifier, but got ')'.
+// Try inserting an identifier before ')'.
+//   late var (_) = x;
+//              ^
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:14: Error: Unexpected token ';'.
+//   late var (_) = x;
+//              ^
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:16: Error: Expected an identifier, but got '='.
+// Try inserting an identifier before '='.
+//   late var (_) = x;
+//                ^
+//
+import self as self;
+
+static method f(dynamic x) → dynamic {}

pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart.textual_outline.expect

@@ -0,0 +1 @@
+f(x) {}

pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart.textual_outline_modelled.expect

@@ -0,0 +1 @@
+f(x) {}

pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart.weak.expect

@@ -0,0 +1,38 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:12: Error: Expected an identifier, but got '('.
+// Try inserting an identifier before '('.
+//   late var (_) = x;
+//            ^
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:12: Error: Expected ';' after this.
+//   late var (_) = x;
+//            ^
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:13: Error: Expected ';' after this.
+//   late var (_) = x;
+//             ^
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:13: Error: Undefined name '_'.
+//   late var (_) = x;
+//             ^
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:14: Error: Expected an identifier, but got ')'.
+// Try inserting an identifier before ')'.
+//   late var (_) = x;
+//              ^
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:14: Error: Unexpected token ';'.
+//   late var (_) = x;
+//              ^
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:16: Error: Expected an identifier, but got '='.
+// Try inserting an identifier before '='.
+//   late var (_) = x;
+//                ^
+//
+import self as self;
+
+static method f(dynamic x) → dynamic {}

pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart.weak.modular.expect

@@ -0,0 +1,38 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:12: Error: Expected an identifier, but got '('.
+// Try inserting an identifier before '('.
+//   late var (_) = x;
+//            ^
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:12: Error: Expected ';' after this.
+//   late var (_) = x;
+//            ^
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:13: Error: Expected ';' after this.
+//   late var (_) = x;
+//             ^
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:13: Error: Undefined name '_'.
+//   late var (_) = x;
+//             ^
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:14: Error: Expected an identifier, but got ')'.
+// Try inserting an identifier before ')'.
+//   late var (_) = x;
+//              ^
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:14: Error: Unexpected token ';'.
+//   late var (_) = x;
+//              ^
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:16: Error: Expected an identifier, but got '='.
+// Try inserting an identifier before '='.
+//   late var (_) = x;
+//                ^
+//
+import self as self;
+
+static method f(dynamic x) → dynamic {}

pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart.weak.outline.expect

@@ -0,0 +1,5 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+
+static method f(dynamic x) → dynamic
+  ;

pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart.weak.transformed.expect

@@ -0,0 +1,38 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:12: Error: Expected an identifier, but got '('.
+// Try inserting an identifier before '('.
+//   late var (_) = x;
+//            ^
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:12: Error: Expected ';' after this.
+//   late var (_) = x;
+//            ^
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:13: Error: Expected ';' after this.
+//   late var (_) = x;
+//             ^
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:13: Error: Undefined name '_'.
+//   late var (_) = x;
+//             ^
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:14: Error: Expected an identifier, but got ')'.
+// Try inserting an identifier before ')'.
+//   late var (_) = x;
+//              ^
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:14: Error: Unexpected token ';'.
+//   late var (_) = x;
+//              ^
+//
+// pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_disallowsLate.dart:6:16: Error: Expected an identifier, but got '='.
+// Try inserting an identifier before '='.
+//   late var (_) = x;
+//                ^
+//
+import self as self;
+
+static method f(dynamic x) → dynamic {}

pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_noMetadata_final_extractor.dart

@@ -0,0 +1,7 @@
+// Copyright (c) 2022, 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.
+
+f(x) {
+  final C(f: a) = x;
+}

pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_noMetadata_final_extractor.dart.strong.expect

@@ -0,0 +1,6 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+
+static method f(dynamic x) → dynamic {
+  invalid-expression "PatternVariableDeclaration(final <dummy-pattern> = x;)";
+}

pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_noMetadata_final_extractor.dart.strong.transformed.expect

@@ -0,0 +1,6 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+
+static method f(dynamic x) → dynamic {
+  invalid-expression "PatternVariableDeclaration(final <dummy-pattern> = x;)";
+}

pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_noMetadata_final_extractor.dart.textual_outline.expect

@@ -0,0 +1 @@
+f(x) {}

pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_noMetadata_final_extractor.dart.textual_outline_modelled.expect

@@ -0,0 +1 @@
+f(x) {}

pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_noMetadata_final_extractor.dart.weak.expect

@@ -0,0 +1,6 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+
+static method f(dynamic x) → dynamic {
+  invalid-expression "PatternVariableDeclaration(final <dummy-pattern> = x;)";
+}

pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_noMetadata_final_extractor.dart.weak.modular.expect

@@ -0,0 +1,6 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+
+static method f(dynamic x) → dynamic {
+  invalid-expression "PatternVariableDeclaration(final <dummy-pattern> = x;)";
+}

pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_noMetadata_final_extractor.dart.weak.outline.expect

@@ -0,0 +1,5 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+
+static method f(dynamic x) → dynamic
+  ;

pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_noMetadata_final_extractor.dart.weak.transformed.expect

@@ -0,0 +1,6 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+
+static method f(dynamic x) → dynamic {
+  invalid-expression "PatternVariableDeclaration(final <dummy-pattern> = x;)";
+}

pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_noMetadata_var_extractor.dart

@@ -0,0 +1,7 @@
+// Copyright (c) 2022, 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.
+
+f(x) {
+  var C(f: a) = x;
+}

pkg/front_end/testcases/patterns/patternVariableDeclarationStatement_noMetadata_var_extractor.dart.strong.expect

@@ -0,0 +1,6 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+
+static method f(dynamic x) → dynamic {
+  invalid-expression "PatternVariableDeclaration(var <dummy-pattern> = x;)";
+}