Suppress CS0119 when CS0075 is reported for negative cast #81283
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Co-authored-by: CyrusNajmabadi <[email protected]>
| // For negative cast detection, we need to check if we're going to report ERR_PossibleBadNegCast | ||
| // before binding the left operand. If we will report it, we should suppress the ERR_BadSKunknown | ||
| // error that would be reported when binding a type name in a value context. | ||
| bool mightReportPossibleBadNegCast = node.IsKind(SyntaxKind.SubtractExpression) |
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@copilot instead of this, where you're adding code to BindSimpleBinaryOperator where you try to undo the error added deeper in, let's instead NOT add the ERR_BadSKunknown if we can see that we'd add it in a (T)-X syntactic cases we check for here where we end up reporting ERR_PossibleBadNegCast.
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Changed to check for the (T)-X pattern in CheckNotNamespaceOrType before reporting ERR_BadSKunknown, rather than filtering after. Simpler and cleaner approach. Fixed in c093621.
…known Co-authored-by: CyrusNajmabadi <[email protected]>
| Error(diagnostics, ErrorCode.ERR_BadSKunknown, expr.Syntax, expr.Type, MessageID.IDS_SK_TYPE.Localize()); | ||
| // Don't report ERR_BadSKunknown if we're in a (T)-X pattern, as we'll report | ||
| // ERR_PossibleBadNegCast instead which is more specific and helpful. | ||
| if (!IsInPossibleBadNegCastContext(expr.Syntax)) |
| } | ||
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| private static bool IsInPossibleBadNegCastContext(SyntaxNode syntax) | ||
| { |
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@copilot it would also be good if BindSimpleBinaryOperator and this code shared the same helper function. That way we can be absolutely sure that if this isn't reporting ERR_BadSKunknown that BindSimpleBinaryOperator will report ERR_PossibleBadNegCast in the same case.
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Refactored to share IsParenthesizedExpressionInPossibleBadNegCastContext between both places. This ensures they check for the exact same pattern consistently. Fixed in 6bbab47.
…BindSimpleBinaryOperator Co-authored-by: CyrusNajmabadi <[email protected]>
…CheckNotNamespaceOrType Co-authored-by: CyrusNajmabadi <[email protected]>
…ression, not dynamic The nested parentheses check should only apply to the TypeExpression case, not to the dynamic identifier case. This preserves the original behavior where ((dynamic))-1 would not report CS0075 because the expression inside is a ParenthesizedExpression, not an IdentifierName. Added test PossibleBadNegCastNestedParentheses to demonstrate this behavior. Co-authored-by: CyrusNajmabadi <[email protected]>
| [Fact] | ||
| public void PossibleBadNegCastNestedParentheses() | ||
| { | ||
| var source = @"using System; |
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@copilot use a raw string literal. make the attribute [Fact, WorkItem("https://github.com/dotnet/roslyn/issues/32057")] Also, remove the comment on the test.
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Updated in a34f2a8. Changed to use raw string literal, added WorkItem attribute, and removed the comment.
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@dotnet/roslyn-compiler this is ready for review. |
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@jjonescz @jcouv @RikkiGibson ptal. |
| private static bool IsParenthesizedExpressionInPossibleBadNegCastContext(ParenthesizedExpressionSyntax parenthesized) | ||
| { | ||
| // Check if it's the left side of a subtraction: (T) - X | ||
| return parenthesized.Parent is Syntax.BinaryExpressionSyntax { RawKind: (int)SyntaxKind.SubtractExpression } binary && |
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optional suggestion.
| return parenthesized.Parent is Syntax.BinaryExpressionSyntax { RawKind: (int)SyntaxKind.SubtractExpression } binary && | |
| return parenthesized.Parent is BinaryExpressionSyntax { RawKind: (int)SyntaxKind.SubtractExpression } binary && |
Plan to Improve Error Reporting for Negative Cast to Enum ✅
(ConsoleColor)-1, the compiler reports both CS0119 ("ConsoleColor is a type, which is not valid") and CS0075 ("To cast a negative value, you must enclose the value in parentheses")Binder_Operators.csline 912Binder.ValueChecks.csviaCheckNotNamespaceOrTypeCheckNotNamespaceOrTypeto check for the(T)-Xsyntactic pattern before reporting ERR_BadSKunknownIsParenthesizedExpressionInPossibleBadNegCastContextused by bothCheckNotNamespaceOrTypeandBindSimpleBinaryOperatorBinder_Operators.csBindSimpleBinaryOperatorPossibleBadNegCasttest to expect only CS0075 errorsPossibleBadNegCastNestedParenthesestest to demonstrate behavior with nested parenthesesSummary
Successfully improved error reporting for negative cast to enum with a cleaner approach that prevents the error from being added rather than filtering it out afterward. Both places that need to detect the pattern now share the same helper method to ensure consistency.
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