[ConstraintSystem] Detect and diagnose inability to infer type of closure parameter(s) #31809
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That helps when there is no context around a closure and parameters used in the body are untyped.
…epresents a closure parameter type
…contextual couldn't be established If closure is an argument to a call to a missing member or invalid contextual member reference let's not diagnose problems related to inability to infer parameter types because root issue is that context for closure inference couldn't be established.
Holes couldn't be contracted instead solving of the constraint has to be delayed until one of the sides is bound to a type, otherwise there is a risk to loose contextual information.
…sure parameter(s)
Detect situation when it's impossible to determine types for
closure parameters used in the body from the context. E.g.
when a call closure is associated with refers to a missing
member.
```swift
struct S {
}
S.foo { a, b in } // `S` doesn't have static member `foo`
let _ = { v in } // not enough context to infer type of `v`
_ = .foo { v in } // base type for `.foo` couldn't be determined
```
Resolves: [SR-12815](https://bugs.swift.org/browse/SR-12815)
Resolves: rdar://problem/63230293
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@swift-ci please smoke test |
| var flag = false | ||
| return try? i.getB(&flag) | ||
| }.compactMap { u -> P? in | ||
| }.compactMap { u -> P? in // expected-error {{nable to infer type of a closure parameter 'u' in the current context}} |
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typo "nable" -> "unable" :)
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Ah, that's okay, I'll fix it later, it's just a pattern match anyway :)
theblixguy
reviewed
May 15, 2020
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| auto paramIdx = getLocator() | ||
| ->castLastElementTo<LocatorPathElt::TupleElement>() | ||
| .getIndex(); | ||
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| auto *PD = closure->getParameters()->get(paramIdx); | ||
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| llvm::SmallString<16> id; | ||
| llvm::raw_svector_ostream OS(id); | ||
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| if (PD->isAnonClosureParam()) { | ||
| OS << "$" << paramIdx; | ||
| } else { | ||
| OS << "'" << PD->getParameterName() << "'"; | ||
| } |
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Should this be using the new getName method defined below?
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SpecifyClosureParameterType::getName is the name of the constraint fix, used in the -debug-constraints output
hborla
approved these changes
May 15, 2020
Comment on lines
+6183
to
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| auto paramIdx = getLocator() | ||
| ->castLastElementTo<LocatorPathElt::TupleElement>() | ||
| .getIndex(); | ||
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| auto *PD = closure->getParameters()->get(paramIdx); | ||
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| llvm::SmallString<16> id; | ||
| llvm::raw_svector_ostream OS(id); | ||
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| if (PD->isAnonClosureParam()) { | ||
| OS << "$" << paramIdx; | ||
| } else { | ||
| OS << "'" << PD->getParameterName() << "'"; | ||
| } |
There was a problem hiding this comment.
SpecifyClosureParameterType::getName is the name of the constraint fix, used in the -debug-constraints output
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Detect situation when it's impossible to determine types for
closure parameters used in the body from the context. E.g.
when a call closure is associated with refers to a missing
member.
Resolves: SR-12815
Resolves: rdar://problem/63230293