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Sema: Disallow SE-0361 with variadic generic types for now #81304

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Merged
merged 1 commit into from
May 6, 2025
Merged

Sema: Disallow SE-0361 with variadic generic types for now #81304

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2 changes: 1 addition & 1 deletion lib/AST/RequirementMachine/RequirementMachineRequests.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -870,7 +870,7 @@ InferredGenericSignatureRequest::evaluate(
// inferred same-type requirements when building the generic signature of
// an extension whose extended type is a generic typealias.
for (const auto &req : addedRequirements)
requirements.push_back({req, SourceLoc()});
requirements.push_back({req, loc});

desugarRequirements(requirements, inverses, errors);

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13 changes: 13 additions & 0 deletions test/Generics/variadic_generic_types.swift
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Expand Up @@ -116,3 +116,16 @@ func packExpansionInScalarArgument<each T>(_: repeat each T) {
typealias A<U> = U
typealias One = A<repeat each T> // expected-error {{pack expansion 'repeat each T' can only appear in a function parameter list, tuple element, or generic argument of a variadic type}}
}

// Make sure we diagnose instead of silently dropping the same-type requirement
// https://github.com/apple/swift/issues/70432

struct WithPack<each T> {}

// FIXME: The diagnostics are misleading.

extension WithPack<Int, Int> {}
// expected-error@-1 {{same-element requirements are not yet supported}}

extension WithPack where (repeat each T) == (Int, Int) {}
// expected-error@-1 {{generic signature requires types '(repeat each T)' and '(Int, Int)' to be the same}}