Bug 23763 – ICE on operations involving zero-initialized structs

``` struct BigInt { int[64] data; } immutable BigInt a = BigInt.init; void main () { immutable BigInt b; static assert(a == b); } ``` This crashes the compiler: ``` Up to 2.063 : Failure with output: ----- onlineapp.d(8): Error: variable b cannot be read at compile time onlineapp.d(8): while evaluating: static assert(a == b) ----- 2.064 : Status -6 with output: ----- onlineapp.d(8): Error: CTFE internal error: bad compare dmd: ctfeexpr.c:1490: int ctfeRawCmp(Loc, Expression*, Expression*): Assertion `0' failed. ----- 2.065.0: Status -6 with output: ----- onlineapp.d(8): Error: CTFE internal error: bad compare dmd: ctfeexpr.c:1507: int ctfeRawCmp(Loc, Expression*, Expression*): Assertion `0' failed. ----- 2.066.1: Status -6 with output: ----- onlineapp.d(8): Error: CTFE internal error: bad compare dmd: ctfeexpr.c:1424: int ctfeRawCmp(Loc, Expression*, Expression*): Assertion `0' failed. ----- 2.067.1: Status -6 with output: ----- onlineapp.d(8): Error: CTFE internal error: bad compare dmd: ctfeexpr.c:1582: int ctfeRawCmp(Loc, Expression*, Expression*): Assertion `0' failed. ----- 2.068.2: Status -6 with output: ----- onlineapp.d(8): Error: CTFE internal error: bad compare dmd: ctfeexpr.c:1601: int ctfeRawCmp(Loc, Expression*, Expression*): Assertion `0' failed. ----- 2.069.2 to 2.073.2: Segfault with output: onlineapp.d(8): Error: CTFE internal error: bad compare 2.074.1 to 2.078.3: Segfault with output: onlineapp.d(8): Error: CTFE internal error: bad compare of `BigInt([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0])` and `0` Since 2.079.1: Status -4 with output: onlineapp.d(8): Error: CTFE internal error: bad compare of `BigInt([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0])` and `0` ```

@Geod24 created dlang/dmd pull request #14966 "Fix 23763: Correctly handle struct constants with 0 initializer" fixing this issue: - Fix 23763: Correctly handle struct constants with 0 initializer At the moment, in dsymbolsem.d:1026, there is the following comment: ``` /* If a struct is all zeros, as a special case * set its initializer to the integer 0. * In AssignExp::toElem(), we check for this and issue * a memset() to initialize the struct. * Must do same check in interpreter. */ ``` Turns out, the 'Must do same check in interpreter.' part was missing. https://github.com/dlang/dmd/pull/14966

dlang/dmd pull request #14966 "Fix 23763: Correctly handle struct constants with 0 initializer" was merged into stable: - 21baff377725b8cdd702abf0ea148fa095a0a014 by Geod24: Fix 23763: Correctly handle struct constants with 0 initializer At the moment, in dsymbolsem.d:1026, there is the following comment: ``` /* If a struct is all zeros, as a special case * set its initializer to the integer 0. * In AssignExp::toElem(), we check for this and issue * a memset() to initialize the struct. * Must do same check in interpreter. */ ``` Turns out, the 'Must do same check in interpreter.' part was missing. https://github.com/dlang/dmd/pull/14966

dlang/dmd pull request #14992 "merge stable" was merged into master: - 5f15d561410277a0bff1a178f44486e055b3646e by Geod24: Fix 23763: Correctly handle struct constants with 0 initializer At the moment, in dsymbolsem.d:1026, there is the following comment: ``` /* If a struct is all zeros, as a special case * set its initializer to the integer 0. * In AssignExp::toElem(), we check for this and issue * a memset() to initialize the struct. * Must do same check in interpreter. */ ``` Turns out, the 'Must do same check in interpreter.' part was missing. https://github.com/dlang/dmd/pull/14992