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Allan Shortlidge
8a0f76861d
Allow developers to control the behavior of warnings like this:
```
let x = 0
if case _ = x { // warning: 'if' condition is always true
// ...
}
```
Resolves rdar://178154296.
37 lines
1.3 KiB
Markdown
37 lines
1.3 KiB
Markdown
# Useless conditional statement (UselessConditionalStatement)
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Warnings that identify conditional statements (`if`, `while`, and `guard`) whose conditions can never be false.
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## Overview
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When the condition of an `if`, `while`, or `guard` statement is statically known to always be true, the conditional structure is unnecessary. For `if` and `while`, the body always executes (and a `while` loop with no `break` would never terminate); for `guard`, the `else` branch is unreachable.
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## Examples
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```
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let x = 0
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if case _ = x { // warning: 'if' condition is always true
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// ...
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}
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while case _ = x { // warning: 'while' condition is always true
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break
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}
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guard case _ = x else { // warning: 'guard' condition is always true, body is unreachable
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fatalError()
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}
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```
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In the examples above, the pattern matching conditions (`case _ = ...`) can never fail.
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## See Also
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- [If Statement][if-statement]
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- [Guard Statement][guard-statement]
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- [While Statement][while-statement]
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[if-statement]: https://docs.swift.org/swift-book/documentation/the-swift-programming-language/statements/#If-Statement
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[guard-statement]: https://docs.swift.org/swift-book/documentation/the-swift-programming-language/statements/#Guard-Statement
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[while-statement]: https://docs.swift.org/swift-book/documentation/the-swift-programming-language/statements/#While-Statement
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