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Sema: Fix crash on circular reference in checkContextualRequirements() #32776

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Merged
merged 2 commits into from
Jul 9, 2020
Merged

Sema: Fix crash on circular reference in checkContextualRequirements() #32776

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94e9263
Sema: Fix crash on circular reference in checkContextualRequirements()
slavapestov Jul 9, 2020
1f5433f
Add regression test for rdar://64759168
slavapestov Jul 9, 2020
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11 changes: 10 additions & 1 deletion lib/Sema/TypeCheckType.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -619,6 +619,8 @@ static Type checkContextualRequirements(Type type,
return type;
}

auto &ctx = dc->getASTContext();

SourceLoc noteLoc;
{
// We are interested in either a contextual where clause or
Expand All @@ -637,6 +639,13 @@ static Type checkContextualRequirements(Type type,

const auto subMap = parentTy->getContextSubstitutions(decl->getDeclContext());
const auto genericSig = decl->getGenericSignature();
if (!genericSig) {
ctx.Diags.diagnose(loc, diag::recursive_decl_reference,
decl->getDescriptiveKind(), decl->getName());
decl->diagnose(diag::kind_declared_here, DescriptiveDeclKind::Type);
return ErrorType::get(ctx);
}

const auto result =
TypeChecker::checkGenericArguments(
dc, loc, noteLoc, type,
Expand All @@ -647,7 +656,7 @@ static Type checkContextualRequirements(Type type,
switch (result) {
case RequirementCheckResult::Failure:
case RequirementCheckResult::SubstitutionFailure:
return ErrorType::get(dc->getASTContext());
return ErrorType::get(ctx);
case RequirementCheckResult::Success:
return type;
}
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15 changes: 15 additions & 0 deletions validation-test/compiler_crashers_2_fixed/rdar64759168.swift
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@@ -0,0 +1,15 @@
// RUN: %target-swift-frontend -emit-ir %s

public class Clazz {}

public protocol SelectableFieldValueProtocol {}

public protocol FieldProtocol {
associatedtype SelectableValue : SelectableFieldValueProtocol
}

public protocol SelectFieldValueCoordinatorDelegate {
associatedtype Field : Clazz, FieldProtocol
}

public class SelectFieldValueCoordinator<Field, Delegate : SelectFieldValueCoordinatorDelegate> where Field == Delegate.Field {}
12 changes: 12 additions & 0 deletions validation-test/compiler_crashers_2_fixed/rdar64992293.swift
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@@ -0,0 +1,12 @@
// RUN: not %target-swift-frontend -typecheck %s

public protocol SomeProtocol {}

public struct Impl<Param>: SomeProtocol where Param: SomeProtocol {}

public struct Wrapper<Content> where Content: SomeProtocol {}

public extension Wrapper where Content == Impl<WrapperParam> {
typealias WrapperParam = SomeProtocol
}

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Collaborator

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Slightly more reduced:

protocol SomeProtocol {}
struct G<T> {}

struct Wrapper<Content: SomeProtocol> {}

extension Wrapper where Content == G<Wrapper.WrapperParam> {
  typealias WrapperParam = Never
}

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The original test case came from a radar. I like to keep those mostly as-is, in case they uncover more bugs in the future.