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bf71ec8599
We silently miscompiled previously the following code:
protocol Gesture {}
struct Foo {}
struct Bar {}
enum FooOrBar {
case foo(Foo)
case bar(Bar)
}
func main(_ f : FooOrBar) {
switch f {
case .foo(let data as Gesture),
.bar(let data as Gesture):
...
}
...
}
This was because the multiple pattern per case code never implemented support
for address only types.
Now instead of miscompiling such programs, we do the following:
1. We emit an error.
2. When we construct the arguments for the named bindings, we just skip the
address only types. Everything else is normal.
3. In the case block, we use a SILUndef for the address only value.
This ensures that we preserve as many other diagnostics as possible.
rdar://32525952
P.S. As an additional benefit, this eliminates a source of address phi nodes
from SILGen.
47 lines
1.7 KiB
Swift
47 lines
1.7 KiB
Swift
// RUN: %target-swift-frontend %s -o /dev/null -emit-silgen -verify
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protocol GestureData {}
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struct PanData : GestureData {}
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struct PinchData : GestureData {}
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enum Gesture {
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case pan(PanData)
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case pinch(PinchData)
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}
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func testProtocolType(_ a : Gesture) {
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switch a {
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case .pan(let data as GestureData), // expected-error {{matching a protocol value in multiple patterns is not yet supported; use separate cases instead}}
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.pinch(let data as GestureData):
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print(data)
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}
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// This switch makes sure that we preserve the CFG so that dead code warnings do not show up. It also ensures that in at least two cases, we get one error per switch.
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switch a {
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case .pan(let data as GestureData), // expected-error {{matching a protocol value in multiple patterns is not yet supported; use separate cases instead}}
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.pinch(let data as GestureData):
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print(data)
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}
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}
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func testGenericType<T, T2>(_ t : T, _ t2 : T2, _ a : Any, _ b : Any) -> T? {
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switch (a, b) {
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case (let x as T, _), // expected-error {{matching a generic value in multiple patterns is not yet supported; use separate cases instead}}
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(_, let x as T):
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return x
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// This warning check is to ensure that we allow for warnings to be emitting in case blocks.
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print("found it!") // expected-warning {{code after 'return' will never be executed}}
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case (let x as T, let y as T2):
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print(x)
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print(y)
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break
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default:
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return nil
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// This warning check is to ensure that we allow for warnings to be emitting in case blocks.
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print("we failed = (") // expected-warning {{code after 'return' will never be executed}}
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}
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return nil
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print("we failed = (") // expected-warning {{code after 'return' will never be executed}}
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}
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