Merge #817

817: Remove bad mutability check pass r=philberty a=philberty

This was an initial pass to try and ensure all assignments were valid
with respect to the binding mutability. This pass cannot be done at the
name resolution level and in rustc is achieved on mir as part of the borrow
checker. This patch removes this pass and associated test cases.

This set of patches also adds support for indirection around array index
expressions.

Fixes #815 

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

1 files changed, 24 insertions, 2 deletions

diff --git a/gcc/rust/backend/rust-compile-expr.h b/gcc/rust/backend/rust-compile-expr.h
index 2bf969b..46d501a 100644
--- a/gcc/rust/backend/rust-compile-expr.h
+++ b/gcc/rust/backend/rust-compile-expr.h
@@ -390,10 +390,32 @@ public:
 
   void visit (HIR::ArrayIndexExpr &expr) override
   {
-    tree array = CompileExpr::Compile (expr.get_array_expr (), ctx);
+    tree array_reference = CompileExpr::Compile (expr.get_array_expr (), ctx);
     tree index = CompileExpr::Compile (expr.get_index_expr (), ctx);
+
+    // lets check if the array is a reference type then we can add an
+    // indirection if required
+    TyTy::BaseType *array_expr_ty = nullptr;
+    bool ok = ctx->get_tyctx ()->lookup_type (
+      expr.get_array_expr ()->get_mappings ().get_hirid (), &array_expr_ty);
+    rust_assert (ok);
+
+    // do we need to add an indirect reference
+    if (array_expr_ty->get_kind () == TyTy::TypeKind::REF)
+      {
+	TyTy::ReferenceType *r
+	  = static_cast<TyTy::ReferenceType *> (array_expr_ty);
+	TyTy::BaseType *tuple_type = r->get_base ();
+	tree array_tyty = TyTyResolveCompile::compile (ctx, tuple_type);
+
+	array_reference
+	  = ctx->get_backend ()->indirect_expression (array_tyty,
+						      array_reference, true,
+						      expr.get_locus ());
+      }
+
     translated
-      = ctx->get_backend ()->array_index_expression (array, index,
+      = ctx->get_backend ()->array_index_expression (array_reference, index,
 						     expr.get_locus ());
   }