December 15, 2023
https://issues.dlang.org/show_bug.cgi?id=24282

          Issue ID: 24282
           Summary: Error in the code is not detected by the compiler and
                    only fails at the linking stage
           Product: D
           Version: D2
          Hardware: x86_64
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P1
         Component: dmd
          Assignee: nobody@puremagic.com
          Reporter: siarhei.siamashka@hotmail.com

Testcase:

    import std.stdio, std.algorithm;
    int dummyhash(string s) {
        return 0;
    }
    void main() {
        auto input = ["a", "b"];
        input.map!(s => s.map!dummyhash).writeln;
    }

The code is incorrect (the "map!" part shouldn't be there), but the compiler can't see this and only the linker fails:

$ dmd-2.106.0 testcase.d
/usr/lib/gcc/x86_64-pc-linux-gnu/13/../../../../x86_64-pc-linux-gnu/bin/ld:
testcase.o: in function
`_D3std9algorithm9iteration__T3mapS_D8testcase9dummyhashFAyaZiZ__TQBkTQnZQBrFNaNbNiNfQBcZSQDjQDiQDb__T9MapResultS_DQDaQCuQCnTQCqZQBb':
testcase.d:(.text._D3std9algorithm9iteration__T3mapS_D8testcase9dummyhashFAyaZiZ__TQBkTQnZQBrFNaNbNiNfQBcZSQDjQDiQDb__T9MapResultS_DQDaQCuQCnTQCqZQBb[_D3std9algorithm9iteration__T3mapS_D8testcase9dummyhashFAyaZiZ__TQBkTQnZQBrFNaNbNiNfQBcZSQDjQDiQDb__T9MapResultS_DQDaQCuQCnTQCqZQBb]+0x30):
undefined reference to
`_D3std9algorithm9iteration__T9MapResultS_D8testcase9dummyhashFAyaZiTQgZQBq6__ctorMFNaNbNcNiNfQBfZSQDsQDrQDk__TQDdS_DQCwQCqQCjTQCmZQDx'
collect2: error: ld returned 1 exit status
Error: linker exited with status 1


Also it's interesting that this triggers an ICE for GDC with the old frontend:

$ gdc-11.3.0 testcase.d
d21: internal compiler error: in ErrorStatement, at d/dmd/statement.c:290
Please submit a full bug report,
with preprocessed source if appropriate.
See <https://bugs.gentoo.org/> for instructions.

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