Bug 10141 – wrong error message with Tuple!(int) : Error: static assert "Cannot put a char[] into a Appender!(string)"

---- main.d: import std.typecons; import std.typecons:unexisting_symbol; Tuple!(int) fun(){return Tuple!(int).init;} ---- dmd 2.062: dmd main.d: main.d:Error: module std.typecons import 'unexisting_symbol' not found (which is correct) dmd 2.063(beta5): dmd main.d: main.d: Error: module std.typecons import 'unexisting_symbol' not found dmd2_063_beta5/osx/bin/../../src/phobos/std/range.d(611): Error: static assert "Cannot put a char[] into a Appender!(string)" dmd2_063_beta5/osx/bin/../../src/phobos/std/format.d(1433): instantiated from here: put!(Appender!(string), char[]) dmd2_063_beta5osx/bin/../../src/phobos/std/format.d(1335): instantiated from here: formatUnsigned!(Appender!(string), char) dmd2_063_beta5/osx/bin/../../src/phobos/std/format.d(1309): instantiated from here: formatIntegral!(Appender!(string), ulong, char) dmd2_063_beta5/osx/bin/../../src/phobos/std/format.d(2950): ... (3 instantiations, -v to show) ... dmd2_063_beta5/osx/bin/../../src/phobos/std/typecons.d(326): instantiated from here: format!(char, ulong, ulong) main.d(3): instantiated from here: Tuple!(int) (which is incorrect : the stuff after the 1st line doesnt' make sense) I'm on osx if that matters.

Looks like another case of http://d.puremagic.com/issues/show_bug.cgi?id=9549. That one was closed after it was fixed by accident: https://github.com/D-Programming-Language/dmd/pull/1676#issuecomment-14059594 Apparently it's resurfaced again in this new test-case.

(In reply to comment #1) > Looks like another case of http://d.puremagic.com/issues/show_bug.cgi?id=9549. > That one was closed after it was fixed by accident: > https://github.com/D-Programming-Language/dmd/pull/1676#issuecomment-14059594 > > Apparently it's resurfaced again in this new test-case. This 'regression' is not caused by the compiler change. It is introduced by a Phobo change: https://github.com/D-Programming-Language/phobos/commit/895550649f07dabfb0d8fc7693027e86065b3e57 I think that essentially incomplete compiler's template error report mechanism would be the root cause of such redundant errors.

I think this is not a blocker regression against 2.063 release. Change the importance.

A bit more reduced: --- import std.typecons; lets cause_an_error; Tuple!int tf; --- I have seen this bug hiding other erros, so only the "static assert "Cannot put a char[] into a Appender!(string)"" error and the instantiation trace shows up. This becomes really really bad in big code bases. I've experienced this multiple times.

(In reply to comment #4) > This becomes really really bad in big code bases. I've > experienced this multiple times. Yeah me too, lately quite often.

Commits pushed to master at https://github.com/D-Programming-Language/dmd https://github.com/D-Programming-Language/dmd/commit/8c5cce3e6ffd63ad3af23caf2e15ea7a3eabeea5 fix Issue 10141 - wrong error message with Tuple!(int) : Error: static assert "Cannot put a char[] into a Appender!(string)" Essentially it's bad code if it branches based on the condition `global.errors != 0`. https://github.com/D-Programming-Language/dmd/commit/390a9340cad6f9c44757cd4782792b08d95a56ba Merge pull request #2346 from 9rnsr/fix10141 Issue 10141 - wrong error message with Tuple!(int) : Error: static assert "Cannot put a char[] into a Appender!(string)"