Paul Berry
104ac30cf4
The listener API for variable patterns is split into three separate functions, to handle the three separate behaviors: - `handleAssignedVariablePattern` for variable names appearing in an assignment context (these assign to an existing variable upon a successful match). - `handleDeclaredVariablePattern` for variable declarations appearing in a declaration or matching context (these cause a new variable name to come into scope). - `handleWildcardPattern` for wildcards in any context (these don't capture the matched value). Also, responsibility is shifted to the parser for reporting the following error conditions: - VariablePatternKeywordInDeclarationContext (e.g. `var (var x) = ...;`) - PatternAssignmentDeclaresVariable (e.g. `[x, var y] = ...;`) Previously these errors were detected by the implementations, and weren't fully covering all possible error scenarios. In the case of VariablePatternKeywordInDeclarationContext, the listener method `handleDeclaredVariablePattern` is called instead of `handleAssignedVariablePattern`. This ensures that no tokens are dropped from the analyzer AST. The CFE uses the `inAssignmentPattern` argument of `handleDeclaredVariablePattern` to distinguish this error recovery case from a legitimate declared variable pattern. Fixes #51868. Bug: https://github.com/dart-lang/sdk/issues/51868 Change-Id: I28ec679b73d64033166721c6460be35f15e23171 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/291583 Reviewed-by: Jens Johansen <jensj@google.com> Commit-Queue: Paul Berry <paulberry@google.com>
35 lines
1.4 KiB
Plaintext
35 lines
1.4 KiB
Plaintext
Problems reported:
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parser/patterns/declaredVariable_inPatternAssignment_usingFinal:2:13: Variable 'd' can't be declared in a pattern assignment.
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[a, final d] = y;
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^
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beginCompilationUnit(void)
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beginMetadataStar(void)
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endMetadataStar(0)
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beginTopLevelMember(void)
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beginTopLevelMethod(, null, null)
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handleVoidKeyword(void)
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handleIdentifier(f, topLevelFunctionDeclaration)
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handleNoTypeVariables(()
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beginFormalParameters((, MemberKind.TopLevelMethod)
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endFormalParameters(0, (, ), MemberKind.TopLevelMethod)
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handleAsyncModifier(null, null)
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beginBlockFunctionBody({)
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handleNoTypeArguments([)
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handleAssignedVariablePattern(a)
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handleNoType(final)
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handleRecoverableError(Message[PatternAssignmentDeclaresVariable, Variable 'd' can't be declared in a pattern assignment., Try using a preexisting variable or changing the assignment to a pattern variable declaration., {name: d}], d, d)
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handleDeclaredVariablePattern(final, d, true)
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handleListPattern(2, [, ])
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handleIdentifier(y, expression)
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handleNoTypeArguments(;)
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handleNoArguments(;)
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handleSend(y, ;)
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handlePatternAssignment(=)
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handleExpressionStatement(;)
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endBlockFunctionBody(1, {, })
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endTopLevelMethod(void, null, })
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endTopLevelDeclaration()
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endCompilationUnit(1, )
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