https://issues.dlang.org/show_bug.cgi?id=23091

          Issue ID: 23091
           Summary: importC: string literals no longer convert to D string
                    type
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Keywords: ImportC
          Severity: normal
          Priority: P1
         Component: dmd
          Assignee: nobody@puremagic.com
          Reporter: duser@neet.fi
                CC: duser@neet.fi

// dmodule.d
void d_fn(string s){}
string d_var;
// test.c
__import dmodule;
void fn()
{
        d_fn("a");
        d_var = "b";
}

test.c(4): Error: function `dmodule.d_fn(string s)` is not callable using
argument types `(char*)`
test.c(4):        cannot pass argument `"a"` of type `char*` to parameter
`string s`
test.c(5): Error: cannot implicitly convert expression `"b"` of type `char*` to
`string`

this worked before https://github.com/dlang/dmd/pull/14027

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