[cxx-interop] Allow using std::map subscript
#61385
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| if (!typeDecl || !parameterType) | ||
| return nullptr; | ||
| if (parameter->isInOut()) | ||
| // Subscripts with inout parameters are not allowed in Swift. | ||
| return nullptr; |
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We should transform this to a non-inout parameter.
If you're not going to fix this in the next week or two please add a diagnostic here as well.
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Oh I missed what this is actually doing, this makes the other overload becomes usable. This is lower priority, then.
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It's quite challenging to add a useful diagnostic here, since this method only gets invoked from generated Swift code. I think it's not worth the trouble, but let's discuss if you disagree 😉
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This fixes an error that occurred when trying to use the subscript on an instance `std::map`: ``` error: cannot assign through subscript: 'map' is immutable ``` This was happening even with a mutable `std::map` instance. `std::map::operator[]` has two overloads: * `T& operator[]( const Key& key )` * `T& operator[]( Key&& key )` The second one is imported with an `inout` parameter, and we picked it as an implementation of the subscript getter because it was the last of the two overloads to get imported. Swift does not allow subscripts with `inout` parameters. This is checked at the AST level, and those checks do not run for synthesized Swift code. This caused Swift to produce a surprising error which actually indicated that the argument of the subscript, not the instance itself, must be mutable. rdar://100529571
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The test failure on Linux is quite unfortunate but it is a different issue, I'll address it separately (#61412). |
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This fixes an error that occurred when trying to use the subscript on an instance
std::map:This was happening even with a mutable
std::mapinstance.std::map::operator[]has two overloads:T& operator[]( const Key& key )T& operator[]( Key&& key )The second one is imported with an
inoutparameter, and we picked it as an implementation of the subscript getter because it was the last of the two overloads to get imported.Swift does not allow subscripts with
inoutparameters. This is checked at the AST level, and those checks do not run for synthesized Swift code. This caused Swift to produce a surprising error which actually indicated that the argument of the subscript, not the instance itself, must be mutable.rdar://100529571