[Diagnostics] Improve diagnostics of overloaded mutating methods #5808
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/cc @rudkx |
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@swift-ci Please smoke test |
rudkx
requested changes
Nov 28, 2016
| // let answer: Int = 42 | ||
| // S().f(answer) | ||
| // | ||
| // Constraint system generator is going to peek `f(_ f: Float)` as |
| // Such leads to incorrect contextual conversion failure diagnostic because | ||
| // type of the argument is going to resolved as (Int) no matter what. | ||
| // To workaround that fact and improve diagnostic of such cases we are going | ||
| // to try and collect all unviable canddidates for a given call and check if |
| // already established type of the argument expression. | ||
| unviableCandidates.filterList(argType, argLabels); | ||
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| // If one of the inviable candidates matches arguments exactly, |
Add special logic to FailureDiagnosis::visitApplyExpr to
handle situation like following:
struct S {
mutating func f(_ i: Int) {}
func f(_ f: Float) {}
}
Given struct has an overloaded method "f" with a single argument of
multiple different types, one of the overloads is marked as
"mutating", which means it can only be applied on LValue base type.
So when struct is used like this:
let answer: Int = 42
S().f(answer)
Constraint system generator is going to pick `f(_ f: Float)` as
only possible overload candidate because "base" of the call is immutable
and contextual information about argument type is not available yet.
Such leads to incorrect contextual conversion failure diagnostic because
type of the argument is going to resolved as (Int) no matter what.
To workaround that fact and improve diagnostic of such cases we are going
to try and collect all unviable candidates for a given call and check if
at least one of them matches established argument type before even trying
to re-check argument expression.
Resolves: <rdar://problem/28051973>.
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@rudkx Fixed all of the typos (in commit message as well), sorry that this keeps happening... |
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@swift-ci Please smoke test and merge. |
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@rudkx looks like CI which was building macOS crashed :( |
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@xedin I'll try kicking it off again in a little while. |
rudkx
approved these changes
Nov 28, 2016
|
@swift-ci Please smoke test and merge |
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Add special logic to FailureDiagnosis::visitApplyExpr to
handle situation like following:
Given struct has an overloaded method "f" with a single argument of
multiple different types, one of the overloads is marked as
"mutating", which means it can only be applied on LValue base type.
So when struct is used like this:
Constraint system generator is going to pick
f(_ f: Float)asonly possible overload candidate because "base" of the call is immutable
and contextual information about argument type is not available yet.
Such leads to incorrect contextual conversion failure diagnostic because
type of the argument is going to resolved as (Int) no matter what.
To workaround that fact and improve diagnostic of such cases we are going
to try and collect all unviable candidates for a given call and check if
at least one of them matches established argument type before even trying
to re-check argument expression.
Resolves: rdar://problem/28051973.