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Since these different forms of documentation have a similar purpose, and there's already some infrastructure for educational notes, unify all of the diagnostics-related documentation in a single place. We might consider unifying these ideas in the compiler as well, but that's for another day.
36 lines
1.2 KiB
Markdown
36 lines
1.2 KiB
Markdown
# Unsafe code wanings (`Unsafe`)
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This diagnostic group includes warnings that identify the use of unsafe language constructs and library APIs. Example warnings include:
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- Use of an unsafe language feature:
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```swift
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// warning: unowned(unsafe) involves unsafe code
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unowned(unsafe) var parentNode: TreeNode<T>
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```
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- Use of a function or type annotated with `@unsafe`:
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```swift
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// warning: reference to unsafe generic struct 'UnsafeMutablePointer'
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func getPointee<T>(_ pointer: UnsafeMutablePointer<Int>, as type: T.Type) -> T {
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// warning: call to unsafe global function 'unsafeBitCast'
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return unsafeBitCast(pointer.pointee, to: type)
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}
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```
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- Use of a function involving an `@unsafe` type:
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```swift
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func evilMalloc(size: Int) -> Int {
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// warning: call to global function 'malloc' involves unsafe type 'UnsafeMutableRawPointer'
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return Int(bitPattern: malloc(size))
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}
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```
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These warnings can be suppressed using an `unsafe` expression, which acknowledges the presence of memory-unsafe code. For example:
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```swift
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func evilMalloc(size: Int) -> Int {
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return unsafe Int(bitPattern: malloc(size))
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}
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```
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The warnings produced by this diagnostic group can be enabled with the compiler
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flag `-strict-memory-safety`. |