Bug 19969 – Unhelpful error when attempting (incorrectly) to append to a string

void main() { string s; s += "foo"; // Error: slice s is not mutable } Of course, the user meant to use ~=, but many other languages use += so this will be a common occurrence. An error is expected here, but erroring on mutability is unhelpful. It's also incorrect since the slice *is* mutable (even though the elements are not). Note, with a mutable string, you get a more helpful error: void main() { char[] s; s += "foo"; // Error: invalid array operation s += "foo" (possible missing []) } The enhancement request here is for a better error. Preferably something mentioning that the operation is invalid.

@Basile-z created dlang/dmd pull request #10039 "fix issue 19969 - Unhelpful error when attempting (incorrectly) to append to a string" fixing this issue: - fix issue 19969 - Unhelpful error when attempting (incorrectly) to append to a string https://github.com/dlang/dmd/pull/10039

dlang/dmd pull request #10039 "fix issue 19969 - Unhelpful error when attempting (incorrectly) to append to a string" was merged into master: - b9d80468daebb9ba0b6bb8df0e3d78c03965dbb8 by Basile Burg: fix issue 19969 - Unhelpful error when attempting (incorrectly) to append to a string https://github.com/dlang/dmd/pull/10039