Bug 22665 – ImportC: qualified enum values should be of enum type on the D side, not int

Consider the following: // an_enum.c enum AnEnum { A = 0, B = 1, }; // use_an_enum.d import an_enum; int foo(AnEnum e){ AnEnum ae = AnEnum.A; // Error: cannot implicitly convert expression `0` of type `int` to `AnEnum` switch(e){ case AnEnum.A: // Error: cannot implicitly convert expression `0` of type `int` to `AnEnum` return 1; case AnEnum.B: // Error: cannot implicitly convert expression `1` of type `int` to `AnEnum` return 2; } } As one of the major benefits of ImportC is getting access to enums defined in C, this is a major problem.

The trouble here is that in C11, 6.7.2.2-3 says "The identifiers in an enumerator list are declared as constants that have type int". I'll see what I can do.

(In reply to Walter Bright from comment #1) > The trouble here is that in C11, 6.7.2.2-3 says "The identifiers in an > enumerator list are declared as constants that have type int". I'll see what > I can do. 6.7.2.4 specifies that "Each enumerated type shall be compatible with char, a signed integer type, or an unsigned integer type. The choice of type is implementation-defined) but shall be capable of representing the values of all the members of the enumeration.”, so the value will always fit.

(In reply to dave287091 from comment #2) > (In reply to Walter Bright from comment #1) > ... > 6.7.2.4 > ... Sorry, 6.7.2.2-4

"shall be capable of representing the values of" is not the same as being the same type.

@WalterBright created dlang/dmd pull request #13520 "fix Issue 22665 - ImportC: qualified enum values should be of enum ty…" fixing this issue: - fix Issue 22665 - ImportC: qualified enum values should be of enum type on the D side, not int https://github.com/dlang/dmd/pull/13520

(In reply to Walter Bright from comment #4) > "shall be capable of representing the values of" is not the same as being > the same type. Yes, but it means that the implicit conversion is safe, in the same way that converting a short to an int is safe, or that (int & 0x7f) is allowed to implicitly convert to byte.

dlang/dmd pull request #13520 "fix Issue 22665 - ImportC: qualified enum values should be of enum ty…" was merged into master: - 0cff8651a892fa3fbfb8564e83c75ac214f7c585 by Walter Bright: fix Issue 22665 - ImportC: qualified enum values should be of enum type on the D side, not int https://github.com/dlang/dmd/pull/13520