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f0eef0f583
Using an unwrap operator with 'as' or the wrong keyword (i.e. `is`) when already checking a cast via ~= results in error: 'pattern variable binding cannot appear in an expression'. Add a diagnostic that provides more guidance and a fix-it for the removal of ?/! or replacement of 'is' with 'as'.
25 lines
1.0 KiB
Swift
25 lines
1.0 KiB
Swift
// RUN: %target-typecheck-verify-swift
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enum E: Error { case e }
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// rdar://106598067 – Make sure we don't crash.
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let fn = {
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do {} catch let x as? E {}
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// expected-error@-1 {{cannot conditionally downcast in a type-casting pattern}}{{23-24=}}
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// expected-error@-2 {{expression pattern of type 'E?' cannot match values of type 'any Error'}}
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// expected-warning@-3 {{'catch' block is unreachable because no errors are thrown in 'do' block}}
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}
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// https://github.com/swiftlang/swift/issues/44631
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let maybeInt: Any = 1
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switch maybeInt {
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case let intValue as? Int: _ = intValue
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// expected-error@-1 {{cannot conditionally downcast in a type-casting pattern}}{{21-22=}}
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// expected-error@-2 {{expression pattern of type 'Int?' cannot match values of type 'Any'}}
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case let intValue as! Int: _ = intValue
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// expected-error@-1 {{cannot force downcast in a type-casting pattern}}{{21-22=}}
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case let intValue is Int: _ = intValue
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// expected-error@-1 {{use 'as' keyword to bind a matched value}}{{19-21=as}}
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default: break
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}
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