[SR-13639][Diag] Don't diagnose local type declarations as unreachable #34493
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@swift-ci please test |
guitard0g
requested review from
devincoughlin,
rjmccall,
atrick,
eeckstein and
slavapestov
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| func sr13639() -> Int { | ||
| return Foo.bar | ||
| struct Foo { // no-warning | ||
| static var bar = 0 |
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Can you define a method inside Foo and add a CHECK: line to ensure the method is actually emitted, too?
Local types can be used earlier within a scope than they were declared. We currently diagnose these type declarations as unreachable when they appear after a return, even though they may have been used prior to the return statement. This change stops that diagnostic. Resolves SR-13639, rdar://69845495
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@swift-ci please test |
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| } else if (auto D = ESD.dyn_cast<Decl*>()) { | ||
| // Local type declarations are not unreachable because they can appear | ||
| // after the declared type has already been used. | ||
| if (isa<TypeDecl>(D)) |
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One more thing I realized: local functions (FuncDecl) need the same treatment, because they can also be forward-referenced. Do you mind adding that in this PR or a follow-up?
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Sure thing. On a related note, while testing I found out forward references in this scenario seem to crash the compiler. That bug may need to be fixed before we can add proper tests for the forward reference scenario.
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@swift-ci please smoke test and merge |
Local types can be used earlier within a scope than they were declared. We currently diagnose these type declarations as unreachable when they appear after a return, even though they may have been used prior to the return statement. This change stops that diagnostic.
Resolves SR-13639, rdar://69845495
Note on local function declarations:
Currently we emit an unreachable code diagnostic when a function appears after a return statement. Because functions can't be used before they are declared (except inside of another local function), this is fine. However, if the proposal to tweak local function scoping were to be implemented, then we would similarly need to skip emitting a diagnostic here when a local function is defined after a return.