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Merged
CyrusNajmabadi merged 2 commits into from
Dec 10, 2025
Merged

Add some lambda parsing tests. #81621

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93bab96
Simplifying lambda parsing to see what might break
CyrusNajmabadi Dec 10, 2025
e110c00
Add tests
CyrusNajmabadi Dec 10, 2025
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116 changes: 116 additions & 0 deletions src/Compilers/CSharp/Test/Syntax/Parsing/LambdaParameterParsingTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -6777,5 +6777,121 @@ public void TestAttributedImplicitParameterWithInitializer()
}
EOF();
}

[Fact]
public void TestParenthesizedLambdaRecovery1()
{
UsingExpression("(int a,) => { }",
// (1,8): error CS1001: Identifier expected
// (int a,) => { }
Diagnostic(ErrorCode.ERR_IdentifierExpected, ")").WithLocation(1, 8));

N(SyntaxKind.ParenthesizedLambdaExpression);
{
N(SyntaxKind.ParameterList);
{
N(SyntaxKind.OpenParenToken);
N(SyntaxKind.Parameter);
{
N(SyntaxKind.PredefinedType);
{
N(SyntaxKind.IntKeyword);
}
N(SyntaxKind.IdentifierToken, "a");
}
N(SyntaxKind.CommaToken);
M(SyntaxKind.Parameter);
{
M(SyntaxKind.IdentifierToken);
}
N(SyntaxKind.CloseParenToken);
}
N(SyntaxKind.EqualsGreaterThanToken);
N(SyntaxKind.Block);
{
N(SyntaxKind.OpenBraceToken);
N(SyntaxKind.CloseBraceToken);
}
}
EOF();
}

[Fact]
public void TestParenthesizedLambdaRecovery2()
{
UsingExpression("(int a, b) => { }");

N(SyntaxKind.ParenthesizedLambdaExpression);
{
N(SyntaxKind.ParameterList);
{
N(SyntaxKind.OpenParenToken);
N(SyntaxKind.Parameter);
{
N(SyntaxKind.PredefinedType);
{
N(SyntaxKind.IntKeyword);
}
N(SyntaxKind.IdentifierToken, "a");
}
N(SyntaxKind.CommaToken);
N(SyntaxKind.Parameter);
{
N(SyntaxKind.IdentifierToken, "b");
}
N(SyntaxKind.CloseParenToken);
}
N(SyntaxKind.EqualsGreaterThanToken);
N(SyntaxKind.Block);
{
N(SyntaxKind.OpenBraceToken);
N(SyntaxKind.CloseBraceToken);
}
}
EOF();
}

[Fact]
public void TestParenthesizedLambdaRecovery3()
{
UsingExpression("(int a, b, ) => { }",
// (1,12): error CS1001: Identifier expected
// (int a, b, ) => { }
Diagnostic(ErrorCode.ERR_IdentifierExpected, ")").WithLocation(1, 12));

N(SyntaxKind.ParenthesizedLambdaExpression);
{
N(SyntaxKind.ParameterList);
{
N(SyntaxKind.OpenParenToken);
N(SyntaxKind.Parameter);
{
N(SyntaxKind.PredefinedType);
{
N(SyntaxKind.IntKeyword);
}
N(SyntaxKind.IdentifierToken, "a");
}
N(SyntaxKind.CommaToken);
N(SyntaxKind.Parameter);
{
N(SyntaxKind.IdentifierToken, "b");
}
N(SyntaxKind.CommaToken);
M(SyntaxKind.Parameter);
{
M(SyntaxKind.IdentifierToken);
}
N(SyntaxKind.CloseParenToken);
}
N(SyntaxKind.EqualsGreaterThanToken);
N(SyntaxKind.Block);
{
N(SyntaxKind.OpenBraceToken);
N(SyntaxKind.CloseBraceToken);
}
}
EOF();
}
}
}