Bug 12478 – Current element in foreach statement is implicitly casted to const

When iterating over aggregate with foreach statement current element is imlicitly casted to const although source aggregate is not surely const. The following code illustrates it. struct S { string str; int num; } class C { private: S[] _items; public: inout(S)* getItemPtr(string str) inout { foreach( ref s; _items ) { if( s.str == str ) { auto itemPtr = &s; pragma(msg, typeof(itemPtr)); //Expected to be inout(s)*. Not inout(const(S))* (in DMD 2.065) or const(S)* (in DMD 2.064) static assert( is( typeof(itemPtr) == inout(S)* ) ); return itemPtr; //Error: not implicitly convertible to inout(S)* } } return null; } } When using inout method in this case result item pointer can address const or mutable data because result is inout(S)*. But operation &s returns pointer of type inout(const(S))* (in 2.064, or const(S)* in previous versions of DMD). So it points to not mutable data in any case. But it expected to be inout(S)*, because method is inout and *this* reference is inout (and all of it's fields without modifiers). So foreach statement iterating over *inout* array should give us inout reference to data, but not const or inout(const).

Fixed from 2.066. *** This issue has been marked as a duplicate of issue 12523 ***