mirror of
https://github.com/nim-lang/Nim.git
synced 2026-09-02 03:43:41 +00:00
33ee586913
Fixes #11797. Imported scalar and pointer aliases inherit their external C spelling, but receive a different Nim symbol. Signature hashing previously used that symbol identity, so aliases that emit exactly the same C type could produce different backend names for tuples, sequences, and other generic types. For example, `cint` and `type CIntAlias = cint` both emit `int`, but `seq[cint]` and `seq[CIntAlias]` could be emitted as incompatible C structs. The Nim type checker nevertheless permits assignments and calls between them, causing the generated C or C++ compilation to fail. This changes the backend hash to use the external type spelling when available. A symbol-based fallback remains for imported types without a resolved spelling. The change deliberately does not collapse imported types into their underlying Nim builtin. Types such as `pid_t`, imported pointers with qualifiers, and platform typedefs may require distinct backend representations. ## NIF and incremental compilation This does not change NIF serialization, NIF type keys, or the IC cache format. The bug is in backend type-name generation. An IC regression test is included to ensure that the corrected backend identity is preserved when compilation passes through the NIF pipeline. ## Tests The regressions cover: - tuple and sequence assignments between an imported type and its alias - cross-module sequence parameters and mutation - C and C++ backends - NIF-backed incremental compilation Existing C-type tests were also run under C/C++, refc, and ARC. ## Remaining scope This does not solve the broader question of compatibility between imported and builtin types that have different backend identities, such as `seq[cdouble]` and `seq[float]`. That remains tracked by #19374.