33 lines
1.3 KiB
Markdown
33 lines
1.3 KiB
Markdown
# Static lambdas
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## Summary
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Support lambdas that disallow capturing state from the enclosing scope.
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## Motivation
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Avoid unintentionally capturing state from the enclosing context.
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## Detailed design
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A lambdas with `static` cannot capture state from the enclosing scope.
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As a result, locals, parameters, and `this` from the enclosing scope are not available within a `static` lambda.
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A `static` lambda cannot reference instance members from an implicit or explicit `this` or `base` reference.
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A `static` lambda may reference `static` members from the enclosing scope.
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A `static` lambda may reference `constant` definitions from the enclosing scope.
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`nameof()` in a `static` lambda may reference locals, parameters, or `this` or `base` from the enclosing scope.
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Accessibility rules for `private` members in the enclosing scope are the same for `static` and non-`static` lambdas.
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No guarantee is made as to whether a `static` lambda definition is emitted as a `static` method in metadata. This is left up to the compiler implementation to optimize.
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A non-`static` local function or lambda can capture state from an enclosing `static` lambda but cannot capture state outside the enclosing `static` lambda.
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A `static` lambda can be used in an expression tree.
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Removing the `static` modifier from a lambda in a valid program does not change the meaning of the program.
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