insertInPlace differences between compilers

[John McFarlane via Digitalmars-d-learn]

I'm trying to write a struct template that uses `insertInPlace`. 
However, it doesn't work with certain template type / compiler 
combinations. Consider the following:

     import std.range;
     struct S { const int c; }
     S[] a;
     insertInPlace(a, 0, S());

With DMD64 D Compiler v2.066.1, I get the following error:
/usr/include/dmd/phobos/std/array.d(1013): Error: cannot modify 
struct dest[i] S with immutable members
/usr/include/dmd/phobos/std/array.d(1079): Error: template 
instance std.array.copyBackwards!(S) error instantiating
./d/my_source_file.d(12345):        instantiated from here: 
insertInPlace!(S, S)

But with gcc version 4.8.2 (Ubuntu 4.8.2-19ubuntu1), the same 
code compiles.

While I'm still trying to get to grips with mutability in D, I 
wonder which compiler/library's got it right or whether this is a 
difference in language versions. The error still occurs when I 
change the type of `c` to a const class which is the case I'd 
really like this to work for.

I can avoid `insertInPlace` on DMD with the following, much 
slower alternative:

     a = a[0..insertionPoint] ~ element ~ a[insertionPoint..$];

In the short term, could anybody suggest a `static if` expression 
to determine whether I can copy the type to the satisfaction of 
`copyBackwards`? I tried isMutable but that didn't seem to work.

Thanks, John