🍒[cxx-interop] Mangle numeric template arguments #67126
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This fixes linker errors when there are multiple instantiations of a templated struct with numeric template parameters. When mangling the name of a C++ template specialization, we currently ignore non-type templated parameters. This causes two different instantiations of the same templated type to have the same mangled name, triggering linker errors. rdar://107757051 (cherry picked from commit d4e8551)
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@swift-ci please test |
DougGregor
approved these changes
Jul 5, 2023
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Explanation: When mangling the name of a C++ template specialization, we ignored non-type templated parameters. This causes two different instantiations of the same templated type to have the same mangled name, triggering linker errors. This change makes sure the compiler adds the numeric arguments into the Swift type name, so they become a part of the mangled type name as well.
Scope: This alters the way templated C++ types with numeric template parameter are imported into Swift, specifically, it changes their type name as seen from Swift code.
Risk: Low, this only has an effect when C++ interop is enabled.
Original PR: #67101
rdar://107757051
(cherry picked from commit d4e8551)