All associative array properties now work as they should.
Fixed problems with some cases of array.length and array.ptr.
Fixed some problems with array properties.
Fixed 'in' contracts.
Fixed some problems with the string runtime support functions.
Fixed initialization of array of structs.
Fixed slice assignment where LHS is slice but RHS is dynamic array.
Fixed problems with result of assignment expressions.
Fixed foreach problems with key type mismatches.
Fixed a bunch of bugs with return/break/continue in loops.
Fixed support for the DMDFE hidden implicit return value variable. This can be needed for some foreach statements where the loop body is converted to a nested delegate, but also possibly returns from the function.
Added std.math to phobos.
Added AA runtime support code, done ground work for implementing AAs.
Several other bugfixes.
