Add initial support for unsized method resolution

In order to support slices, we end up with an operator overload call of:

```
impl<T, I> Index<I> for [T]
where
    I: SliceIndex<[T]>,
{
    type Output = I::Output;

    fn index(&self, index: I) -> &I::Output {
        index.index(self)
    }
}
```

So this means the self in this case is an array[T,capacity] and the index parameter is of type Range<usize>. In order to actually call this method
which has a self parameter of [T] we need to be able to 'unsize' the array
into a slice.

Addresses #849

1 files changed, 3 insertions, 0 deletions

diff --git a/gcc/rust/backend/rust-compile-base.h b/gcc/rust/backend/rust-compile-base.h
index c30aa4d..c7f7f40 100644
--- a/gcc/rust/backend/rust-compile-base.h
+++ b/gcc/rust/backend/rust-compile-base.h
@@ -72,6 +72,9 @@ protected:
   tree resolve_indirection_adjustment (Resolver::Adjustment &adjustment,
 				       tree expression, Location locus);
 
+  tree resolve_unsized_adjustment (Resolver::Adjustment &adjustment,
+				   tree expression, Location locus);
+
   static void setup_attributes_on_fndecl (
     tree fndecl, bool is_main_entry_point, HIR::Visibility &visibility,
     const HIR::FunctionQualifiers &qualifiers, const AST::AttrVec &attrs);