Allow for coercion of structures over to dynamic objects in type system

This is the initial support for allowing a coercion of something like:

```rust
let a = Foo(123);
let b:&dyn Bound = &a;
```

The coercion will need to ensure that 'a' meets the specified bounds of the
dynamic object.

Addresses #197

1 files changed, 11 insertions, 0 deletions

diff --git a/gcc/rust/typecheck/rust-tyty-coercion.h b/gcc/rust/typecheck/rust-tyty-coercion.h
index d46f1d4..976997d 100644
--- a/gcc/rust/typecheck/rust-tyty-coercion.h
+++ b/gcc/rust/typecheck/rust-tyty-coercion.h
@@ -24,6 +24,7 @@
 #include "rust-tyty-visitor.h"
 #include "rust-hir-map.h"
 #include "rust-hir-type-check.h"
+#include "rust-hir-type-bounds.h"
 
 extern ::Backend *
 rust_get_backend ();
@@ -1390,6 +1391,16 @@ public:
     resolved = base->clone ();
   }
 
+  void visit (ADTType &type) override
+  {
+    Location ref_locus = mappings->lookup_location (type.get_ref ());
+    bool ok = base->bounds_compatible (type, ref_locus, true);
+    if (!ok)
+      return;
+
+    resolved = base->clone ();
+  }
+
 private:
   BaseType *get_base () override { return base; }