https://issues.dlang.org/show_bug.cgi?id=24078

          Issue ID: 24078
           Summary: [REG] crash related to concatenation
           Product: D
           Version: D2
          Hardware: x86_64
                OS: Linux
            Status: NEW
          Keywords: wrong-code
          Severity: regression
          Priority: P1
         Component: dmd
          Assignee: nobody@puremagic.com
          Reporter: b2.temp@gmx.com

The following code

```
void main()
{
    import std.stdio;
    auto a = ["c"];
    writeln( a ~ "a"); // OK
    writeln( a ~ "a" ~ "b"); //  CRASH
}
```

used to work and output the right result but it crashes at runtime since recently.

Same problem verified with latest LDC (DMD 2.104.+), showing that the problem might be a caused by a buggy lowering.

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