Bug 10516 – Array length is not checked when array is a manifest constant

----- void main() { enum HexSize = 5; // note: smaller initializer count enum char[HexSize] srcHex = "1234"; char[HexSize] tgtHex = "12345"; // should error with: lengths don't match for array copy assert(tgtHex[0 .. 4] == srcHex); } ----- $ dmd test.d > core.exception.AssertError@test(11): Assertion failure The problem here is that the runtime allowed the left-hand side and right-hand side arrays to be compared even though their lengths do not match. If you convert the source array from a manifest constant into a regular array (by removing enum) then the error is proper: ----- void main() { enum HexSize = 5; // note: smaller initializer count /* enum */ char[HexSize] srcHex = "1234"; char[HexSize] tgtHex = "12345"; assert(tgtHex[0 .. 4] == srcHex); } ----- $ dmd test.d > object.Error: lengths don't match for array copy, 5 = 4

> ----- > void main() > { > enum HexSize = 5; > > // note: smaller initializer count > /* enum */ char[HexSize] srcHex = "1234"; > > char[HexSize] tgtHex = "12345"; > > assert(tgtHex[0 .. 4] == srcHex); > } > ----- > > $ dmd test.d > > object.Error: lengths don't match for array copy, 5 = 4 Actually this test-case is invalid because the error is thrown in the initializer line, not the comparison line. And another thing I just realized is that it's perfectly ok to compare static arrays of non-matching sizes, which makes the whole report invalid.. but I don't understand why this is allowed: void main() { char[5] srcHex = "12345"; char[3] tgtHex = "123"; assert(srcHex == tgtHex); } $ dmd test.d > core.exception.AssertError@test(5): Assertion failure I would have hoped to get a length mismatch error, or even a compile-time error. Oh well..