Bug 23034 – importC: head-const struct confused with multiple files on command line

// file1.c struct S1 { int field1; }; struct S1 *const unused; // file2.c struct S2 { int field2; }; void fn() { struct S2 *const s; int x = s->field2; // here } compile: dmd file1.c file2.c file2.c(7): Error: `field2` is not a member of `const(S1)` similar to issue 23030 but not caused by the same PR (this exists on stable v2.099.1 too)

Ah, took me hours to track this one. The trouble is addSTC() to add in a `const`. In D, this works because type names are identifiers, and mangling is skipped for TypeIdentifier. In C, these come through as a TypeTag, which does get mangled, but semantic() hasn't been run, so S1 and S2 both mangle as "x@" and are therefore treated as the same type.

@WalterBright created dlang/dmd pull request #14016 "fix Issue 23034 - importC: head-const struct confused with multiple f…" fixing this issue: - fix Issue 23034 - importC: head-const struct confused with multiple files on command line https://github.com/dlang/dmd/pull/14016

dlang/dmd pull request #14016 "fix Issue 23034 - importC: head-const struct confused with multiple f…" was merged into master: - 62c0846dd48cef8cf032a552c3e43c18565c42ea by Walter Bright: fix Issue 23034 - importC: head-const struct confused with multiple files on command line https://github.com/dlang/dmd/pull/14016