Merge #1147

1147: Add missing coercion rule from array to slice r=philberty a=philberty

Arrays are coercible into slices, this adds the missing type-resolution
the rule which works for now. The other part of this fix is described in #1146 
for coercion_site to be recursive and reuse the adjustment classes so that
we reuse as much code as possible and handle complex coercion sites.

Fixes #1129


Co-authored-by: Philip Herron <philip.herron@embecosm.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/gcc/rust/typecheck/rust-tyty-coercion.h b/gcc/rust/typecheck/rust-tyty-coercion.h
index c24f17e..e13c7f8 100644
--- a/gcc/rust/typecheck/rust-tyty-coercion.h
+++ b/gcc/rust/typecheck/rust-tyty-coercion.h
@@ -886,6 +886,22 @@ public:
 			      TyVar (base_resolved->get_ref ()));
   }
 
+  void visit (ArrayType &type) override
+  {
+    // check base type
+    auto base_resolved
+      = base->get_element_type ()->unify (type.get_element_type ());
+    if (base_resolved == nullptr)
+      {
+	BaseCoercionRules::visit (type);
+	return;
+      }
+
+    resolved = new SliceType (type.get_ref (), type.get_ty_ref (),
+			      type.get_ident ().locus,
+			      TyVar (base_resolved->get_ref ()));
+  }
+
 private:
   BaseType *get_base () override { return base; }