Bug 11427 – anonymous unions break structs in @safe code

As far s I can see, the problem is that there is a check for pointers in unions in VarDeclaration::semantic, but that relies on AggregateDeclaration::hasUnions, which is set in StructLiteralExp::fill whenever there are overlapping fields. So in addition to the reported problem, a pointer in an anonymous union gets through unnoticed in @safe code: struct S { union { ubyte a; int x; void[] arr; } } int foo() @safe { S s2; return s2.x; }

Hmmm, something wrong with bugzilla? My comment replaced the description, and the initial description is now moved into the first comment.

Compile this code /////////////////// struct S { union { ubyte a; int x; } void[] arr; } int foo() @safe { S s1 = S(); S s2; return 0; } //////////////////// with "dmd -c test.d" fails with test.d(14): Error: variable test.foo.s2 unions containing pointers are not allowed in @safe functions Please note that the first variable s1 is ok! This is also triggered in std.format with this code: import std.format; import std.array; void foo() { FormatSpec!char spec = FormatSpec!char(); auto s = appender!string; formattedWrite(s, "%s", "hello"); }

Commit pushed to master at https://github.com/D-Programming-Language/dmd https://github.com/D-Programming-Language/dmd/commit/090abe1096b94e091e5541cd8ae772624f718a5c fix Issue 11427 - anonymous unions break structs in @safe code