Add support for expression statements beginning with a map pattern.

Bug: #50035, dart-lang/language#2662 Change-Id: Ifb141cf563848fc0035423a625e27585cce2ea57 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/272523 Commit-Queue: Paul Berry <[email protected]> Reviewed-by: Jens Johansen <[email protected]>
dart-lang · Nov 30, 2022 · 701a0d2 · 701a0d2
1 parent 3e00e6a
commit 701a0d2
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Showing 12 changed files with 343 additions and 1 deletion.
diff --git a/pkg/_fe_analyzer_shared/lib/src/parser/parser_impl.dart b/pkg/_fe_analyzer_shared/lib/src/parser/parser_impl.dart
@@ -5240,7 +5240,12 @@ class Parser {
     final String? value = token.next!.stringValue;
     if (identical(value, '{')) {
       // The scanner ensures that `{` always has a closing `}`.
-      return parseBlock(token, BlockKind.statement);
+      if (allowPatterns && optional('=', token.next!.endGroup!.next!)) {
+        // Expression statement beginning with a pattern assignment
+        return parseExpressionStatement(token);
+      } else {
+        return parseBlock(token, BlockKind.statement);
+      }
     } else if (identical(value, 'return')) {
       return parseReturnStatement(token);
     } else if (identical(value, 'var') || identical(value, 'final')) {

diff --git a/pkg/analyzer/test/generated/patterns_parser_test.dart b/pkg/analyzer/test/generated/patterns_parser_test.dart
@@ -3944,6 +3944,20 @@ MapPattern
 ''');
   }
 
+  test_map_insideAssignment_untyped_empty_beginningOfStatement() {
+    _parse('''
+void f(x) {
+  {} = x;
+}
+''');
+    var node = findNode.patternAssignment('= x').pattern;
+    assertParsedNodeText(node, r'''
+MapPattern
+  leftBracket: {
+  rightBracket: }
+''');
+  }
+
   test_map_insideAssignment_untyped_nonEmpty() {
     // Note: statements aren't allowed to start with `{` so we need parens
     // around the assignment.  See
@@ -3974,6 +3988,33 @@ MapPattern
 ''');
   }
 
+  test_map_insideAssignment_untyped_nonEmpty_beginningOfStatement() {
+    _parse('''
+void f(x) {
+  {'a': a, 'b': b} = x;
+}
+''');
+    var node = findNode.patternAssignment('= x').pattern;
+    assertParsedNodeText(node, r'''
+MapPattern
+  leftBracket: {
+  elements
+    MapPatternEntry
+      key: SimpleStringLiteral
+        literal: 'a'
+      separator: :
+      value: VariablePattern
+        name: a
+    MapPatternEntry
+      key: SimpleStringLiteral
+        literal: 'b'
+      separator: :
+      value: VariablePattern
+        name: b
+  rightBracket: }
+''');
+  }
+
   test_map_insideCase_typed_nonEmpty() {
     _parse('''
 void f(x) {

diff --git a/...nd/parser_testcases/patterns/map_insideAssignment_untyped_empty_beginningOfStatement.dart b/...nd/parser_testcases/patterns/map_insideAssignment_untyped_empty_beginningOfStatement.dart
@@ -0,0 +1,3 @@
+void f(x) {
+  {} = x;
+}
diff --git a/...er_testcases/patterns/map_insideAssignment_untyped_empty_beginningOfStatement.dart.expect b/...er_testcases/patterns/map_insideAssignment_untyped_empty_beginningOfStatement.dart.expect
@@ -0,0 +1,31 @@
+beginCompilationUnit(void)
+  beginMetadataStar(void)
+  endMetadataStar(0)
+  beginTopLevelMember(void)
+    beginTopLevelMethod(, null, null)
+      handleVoidKeyword(void)
+      handleIdentifier(f, topLevelFunctionDeclaration)
+      handleNoTypeVariables(()
+      beginFormalParameters((, MemberKind.TopLevelMethod)
+        beginMetadataStar(x)
+        endMetadataStar(0)
+        beginFormalParameter(x, MemberKind.TopLevelMethod, null, null, null)
+          handleNoType(()
+          handleIdentifier(x, formalParameterDeclaration)
+          handleFormalParameterWithoutValue())
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+      endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
+      handleAsyncModifier(null, null)
+      beginBlockFunctionBody({)
+        handleNoTypeArguments({)
+        handleMapPattern(0, {, })
+        handleIdentifier(x, expression)
+        handleNoTypeArguments(;)
+        handleNoArguments(;)
+        handleSend(x, ;)
+        handlePatternAssignment(=)
+        handleExpressionStatement(;)
+      endBlockFunctionBody(1, {, })
+    endTopLevelMethod(void, null, })
+  endTopLevelDeclaration()
+endCompilationUnit(1, )
diff --git a/.../patterns/map_insideAssignment_untyped_empty_beginningOfStatement.dart.intertwined.expect b/.../patterns/map_insideAssignment_untyped_empty_beginningOfStatement.dart.intertwined.expect
@@ -0,0 +1,75 @@
+parseUnit(void)
+  skipErrorTokens(void)
+  listener: beginCompilationUnit(void)
+  syntheticPreviousToken(void)
+  parseTopLevelDeclarationImpl(, Instance of 'DirectiveContext')
+    parseMetadataStar()
+      listener: beginMetadataStar(void)
+      listener: endMetadataStar(0)
+    parseTopLevelMemberImpl()
+      listener: beginTopLevelMember(void)
+      parseTopLevelMethod(, null, null, , Instance of 'VoidType', null, f, false)
+        listener: beginTopLevelMethod(, null, null)
+        listener: handleVoidKeyword(void)
+        ensureIdentifierPotentiallyRecovered(void, topLevelFunctionDeclaration, false)
+          listener: handleIdentifier(f, topLevelFunctionDeclaration)
+        parseMethodTypeVar(f)
+          listener: handleNoTypeVariables(()
+        parseGetterOrFormalParameters(f, f, false, MemberKind.TopLevelMethod)
+          parseFormalParameters(f, MemberKind.TopLevelMethod)
+            parseFormalParametersRest((, MemberKind.TopLevelMethod)
+              listener: beginFormalParameters((, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+                parseMetadataStar(()
+                  listener: beginMetadataStar(x)
+                  listener: endMetadataStar(0)
+                listener: beginFormalParameter(x, MemberKind.TopLevelMethod, null, null, null)
+                listener: handleNoType(()
+                ensureIdentifier((, formalParameterDeclaration)
+                  listener: handleIdentifier(x, formalParameterDeclaration)
+                listener: handleFormalParameterWithoutValue())
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
+        parseAsyncModifierOpt())
+          listener: handleAsyncModifier(null, null)
+          inPlainSync()
+        parseFunctionBody(), false, false)
+          listener: beginBlockFunctionBody({)
+          notEofOrValue(}, {)
+          parseStatement({)
+            parseStatementX({)
+              parseExpressionStatement({)
+                parseExpression({)
+                  looksLikeOuterPatternEquals({)
+                    skipOuterPattern({)
+                  parsePatternAssignment({)
+                    parsePattern({, precedence: 1, isRefutableContext: false)
+                      parsePrimaryPattern({, isRefutableContext: false)
+                        listener: handleNoTypeArguments({)
+                        parseMapPatternSuffix({, isRefutableContext: false)
+                          listener: handleMapPattern(0, {, })
+                    parseExpression(=)
+                      looksLikeOuterPatternEquals(=)
+                        skipOuterPattern(=)
+                          skipObjectPatternRest(x)
+                      parsePrecedenceExpression(=, 1, true)
+                        parseUnaryExpression(=, true)
+                          parsePrimary(=, expression)
+                            parseSendOrFunctionLiteral(=, expression)
+                              parseSend(=, expression)
+                                isNextIdentifier(=)
+                                ensureIdentifier(=, expression)
+                                  listener: handleIdentifier(x, expression)
+                                listener: handleNoTypeArguments(;)
+                                parseArgumentsOpt(x)
+                                  listener: handleNoArguments(;)
+                                listener: handleSend(x, ;)
+                    listener: handlePatternAssignment(=)
+                ensureSemicolon(x)
+                listener: handleExpressionStatement(;)
+          notEofOrValue(}, })
+          listener: endBlockFunctionBody(1, {, })
+        listener: endTopLevelMethod(void, null, })
+  listener: endTopLevelDeclaration()
+  reportAllErrorTokens(void)
+  listener: endCompilationUnit(1, )
diff --git a/...cases/patterns/map_insideAssignment_untyped_empty_beginningOfStatement.dart.parser.expect b/...cases/patterns/map_insideAssignment_untyped_empty_beginningOfStatement.dart.parser.expect
@@ -0,0 +1,9 @@
+void f(x) {
+{} = x;
+}
+
+
+void[KeywordToken] f[StringToken]([BeginToken]x[StringToken])[SimpleToken] {[BeginToken]
+{[BeginToken]}[SimpleToken] =[SimpleToken] x[StringToken];[SimpleToken]
+}[SimpleToken]
+[SimpleToken]
diff --git a/...ases/patterns/map_insideAssignment_untyped_empty_beginningOfStatement.dart.scanner.expect b/...ases/patterns/map_insideAssignment_untyped_empty_beginningOfStatement.dart.scanner.expect
@@ -0,0 +1,9 @@
+void f(x) {
+{} = x;
+}
+
+
+void[KeywordToken] f[StringToken]([BeginToken]x[StringToken])[SimpleToken] {[BeginToken]
+{[BeginToken]}[SimpleToken] =[SimpleToken] x[StringToken];[SimpleToken]
+}[SimpleToken]
+[SimpleToken]
diff --git a/...parser_testcases/patterns/map_insideAssignment_untyped_nonEmpty_beginningOfStatement.dart b/...parser_testcases/patterns/map_insideAssignment_untyped_nonEmpty_beginningOfStatement.dart
@@ -0,0 +1,3 @@
+void f(x) {
+  {'a': a, 'b': b} = x;
+}
diff --git a/...testcases/patterns/map_insideAssignment_untyped_nonEmpty_beginningOfStatement.dart.expect b/...testcases/patterns/map_insideAssignment_untyped_nonEmpty_beginningOfStatement.dart.expect
@@ -0,0 +1,41 @@
+beginCompilationUnit(void)
+  beginMetadataStar(void)
+  endMetadataStar(0)
+  beginTopLevelMember(void)
+    beginTopLevelMethod(, null, null)
+      handleVoidKeyword(void)
+      handleIdentifier(f, topLevelFunctionDeclaration)
+      handleNoTypeVariables(()
+      beginFormalParameters((, MemberKind.TopLevelMethod)
+        beginMetadataStar(x)
+        endMetadataStar(0)
+        beginFormalParameter(x, MemberKind.TopLevelMethod, null, null, null)
+          handleNoType(()
+          handleIdentifier(x, formalParameterDeclaration)
+          handleFormalParameterWithoutValue())
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+      endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
+      handleAsyncModifier(null, null)
+      beginBlockFunctionBody({)
+        handleNoTypeArguments({)
+        beginLiteralString('a')
+        endLiteralString(0, :)
+        handleNoType(:)
+        handleVariablePattern(null, a)
+        handleMapPatternEntry(:, ,)
+        beginLiteralString('b')
+        endLiteralString(0, :)
+        handleNoType(:)
+        handleVariablePattern(null, b)
+        handleMapPatternEntry(:, })
+        handleMapPattern(2, {, })
+        handleIdentifier(x, expression)
+        handleNoTypeArguments(;)
+        handleNoArguments(;)
+        handleSend(x, ;)
+        handlePatternAssignment(=)
+        handleExpressionStatement(;)
+      endBlockFunctionBody(1, {, })
+    endTopLevelMethod(void, null, })
+  endTopLevelDeclaration()
+endCompilationUnit(1, )
diff --git a/...tterns/map_insideAssignment_untyped_nonEmpty_beginningOfStatement.dart.intertwined.expect b/...tterns/map_insideAssignment_untyped_nonEmpty_beginningOfStatement.dart.intertwined.expect
@@ -0,0 +1,107 @@
+parseUnit(void)
+  skipErrorTokens(void)
+  listener: beginCompilationUnit(void)
+  syntheticPreviousToken(void)
+  parseTopLevelDeclarationImpl(, Instance of 'DirectiveContext')
+    parseMetadataStar()
+      listener: beginMetadataStar(void)
+      listener: endMetadataStar(0)
+    parseTopLevelMemberImpl()
+      listener: beginTopLevelMember(void)
+      parseTopLevelMethod(, null, null, , Instance of 'VoidType', null, f, false)
+        listener: beginTopLevelMethod(, null, null)
+        listener: handleVoidKeyword(void)
+        ensureIdentifierPotentiallyRecovered(void, topLevelFunctionDeclaration, false)
+          listener: handleIdentifier(f, topLevelFunctionDeclaration)
+        parseMethodTypeVar(f)
+          listener: handleNoTypeVariables(()
+        parseGetterOrFormalParameters(f, f, false, MemberKind.TopLevelMethod)
+          parseFormalParameters(f, MemberKind.TopLevelMethod)
+            parseFormalParametersRest((, MemberKind.TopLevelMethod)
+              listener: beginFormalParameters((, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+                parseMetadataStar(()
+                  listener: beginMetadataStar(x)
+                  listener: endMetadataStar(0)
+                listener: beginFormalParameter(x, MemberKind.TopLevelMethod, null, null, null)
+                listener: handleNoType(()
+                ensureIdentifier((, formalParameterDeclaration)
+                  listener: handleIdentifier(x, formalParameterDeclaration)
+                listener: handleFormalParameterWithoutValue())
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
+        parseAsyncModifierOpt())
+          listener: handleAsyncModifier(null, null)
+          inPlainSync()
+        parseFunctionBody(), false, false)
+          listener: beginBlockFunctionBody({)
+          notEofOrValue(}, {)
+          parseStatement({)
+            parseStatementX({)
+              parseExpressionStatement({)
+                parseExpression({)
+                  looksLikeOuterPatternEquals({)
+                    skipOuterPattern({)
+                  parsePatternAssignment({)
+                    parsePattern({, precedence: 1, isRefutableContext: false)
+                      parsePrimaryPattern({, isRefutableContext: false)
+                        listener: handleNoTypeArguments({)
+                        parseMapPatternSuffix({, isRefutableContext: false)
+                          parseExpression({)
+                            looksLikeOuterPatternEquals({)
+                              skipOuterPattern({)
+                            parsePrecedenceExpression({, 1, true)
+                              parseUnaryExpression({, true)
+                                parsePrimary({, expression)
+                                  parseLiteralString({)
+                                    parseSingleLiteralString({)
+                                      listener: beginLiteralString('a')
+                                      listener: endLiteralString(0, :)
+                          parsePattern(:, precedence: 1, isRefutableContext: false)
+                            parsePrimaryPattern(:, isRefutableContext: false)
+                              parseVariablePattern(:, typeInfo: Instance of 'NoType')
+                                listener: handleNoType(:)
+                                listener: handleVariablePattern(null, a)
+                          listener: handleMapPatternEntry(:, ,)
+                          parseExpression(,)
+                            looksLikeOuterPatternEquals(,)
+                              skipOuterPattern(,)
+                            parsePrecedenceExpression(,, 1, true)
+                              parseUnaryExpression(,, true)
+                                parsePrimary(,, expression)
+                                  parseLiteralString(,)
+                                    parseSingleLiteralString(,)
+                                      listener: beginLiteralString('b')
+                                      listener: endLiteralString(0, :)
+                          parsePattern(:, precedence: 1, isRefutableContext: false)
+                            parsePrimaryPattern(:, isRefutableContext: false)
+                              parseVariablePattern(:, typeInfo: Instance of 'NoType')
+                                listener: handleNoType(:)
+                                listener: handleVariablePattern(null, b)
+                          listener: handleMapPatternEntry(:, })
+                          listener: handleMapPattern(2, {, })
+                    parseExpression(=)
+                      looksLikeOuterPatternEquals(=)
+                        skipOuterPattern(=)
+                          skipObjectPatternRest(x)
+                      parsePrecedenceExpression(=, 1, true)
+                        parseUnaryExpression(=, true)
+                          parsePrimary(=, expression)
+                            parseSendOrFunctionLiteral(=, expression)
+                              parseSend(=, expression)
+                                isNextIdentifier(=)
+                                ensureIdentifier(=, expression)
+                                  listener: handleIdentifier(x, expression)
+                                listener: handleNoTypeArguments(;)
+                                parseArgumentsOpt(x)
+                                  listener: handleNoArguments(;)
+                                listener: handleSend(x, ;)
+                    listener: handlePatternAssignment(=)
+                ensureSemicolon(x)
+                listener: handleExpressionStatement(;)
+          notEofOrValue(}, })
+          listener: endBlockFunctionBody(1, {, })
+        listener: endTopLevelMethod(void, null, })
+  listener: endTopLevelDeclaration()
+  reportAllErrorTokens(void)
+  listener: endCompilationUnit(1, )
diff --git a/...es/patterns/map_insideAssignment_untyped_nonEmpty_beginningOfStatement.dart.parser.expect b/...es/patterns/map_insideAssignment_untyped_nonEmpty_beginningOfStatement.dart.parser.expect
@@ -0,0 +1,9 @@
+void f(x) {
+{'a': a, 'b': b} = x;
+}
+
+
+void[KeywordToken] f[StringToken]([BeginToken]x[StringToken])[SimpleToken] {[BeginToken]
+{[BeginToken]'a'[StringToken]:[SimpleToken] a[StringToken],[SimpleToken] 'b'[StringToken]:[SimpleToken] b[StringToken]}[SimpleToken] =[SimpleToken] x[StringToken];[SimpleToken]
+}[SimpleToken]
+[SimpleToken]
diff --git a/...s/patterns/map_insideAssignment_untyped_nonEmpty_beginningOfStatement.dart.scanner.expect b/...s/patterns/map_insideAssignment_untyped_nonEmpty_beginningOfStatement.dart.scanner.expect
@@ -0,0 +1,9 @@
+void f(x) {
+{'a': a, 'b': b} = x;
+}
+
+
+void[KeywordToken] f[StringToken]([BeginToken]x[StringToken])[SimpleToken] {[BeginToken]
+{[BeginToken]'a'[StringToken]:[SimpleToken] a[StringToken],[SimpleToken] 'b'[StringToken]:[SimpleToken] b[StringToken]}[SimpleToken] =[SimpleToken] x[StringToken];[SimpleToken]
+}[SimpleToken]
+[SimpleToken]