Clang produces a warning about incompatible linkage for templated type
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Description
This warning will soon be filtered out but we need to fix it at some point.
/gcc/rust/ast/rust-fmt.h:403:15: warning: 'collect_pieces' has C-linkage specified, but returns incomplete type 'FFIVec<Piece>' which could be incompatible with C [-Wreturn-type-c-linkage]
/gcc/rust/ast/rust-fmt.h:406:15: warning: 'clone_pieces' has C-linkage specified, but returns incomplete type 'FFIVec<Piece>' which could be incompatible with C [-Wreturn-type-c-linkage]
I expected this code to be rejected by both clang and gcc.
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Research direction
Start in gcc/rust/ast/rust-fmt.h around lines 403 and 406, where collect_pieces and clone_pieces return FFIVec with C linkage. Reproduce the diagnostics with Clang and GCC, then trace the declarations and linkage rules to determine the expected rejection behavior. Done means the incompatible-linkage warning is handled consistently by both compilers without relying on filtering.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- cpp
- Domain
- compilers
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 42/100