4 files changed, 19 insertions, 60 deletions

diff --git a/gcc/rust/backend/rust-compile-expr.cc b/gcc/rust/backend/rust-compile-expr.cc
index 1048027..ae4a841 100644
--- a/gcc/rust/backend/rust-compile-expr.cc
+++ b/gcc/rust/backend/rust-compile-expr.cc
@@ -397,13 +397,11 @@ CompileExpr::visit (HIR::CallExpr &expr)
       std::vector<tree> ctor_arguments;
       if (adt->is_enum ())
 	{
-	  HirId variant_id = variant->get_id ();
-	  mpz_t val;
-	  mpz_init_set_ui (val, variant_id);
+	  HIR::Expr *discrim_expr = variant->get_discriminant ();
+	  tree discrim_expr_node = CompileExpr::Compile (discrim_expr, ctx);
+	  tree folded_discrim_expr = ConstCtx::fold (discrim_expr_node);
+	  tree qualifier = folded_discrim_expr;
 
-	  tree t = TyTyResolveCompile::get_implicit_enumeral_node_type (ctx);
-	  tree qualifier
-	    = double_int_to_tree (t, mpz_get_double_int (t, val, true));
 	  ctor_arguments.push_back (qualifier);
 	}
       for (auto &arg : arguments)
diff --git a/gcc/rust/backend/rust-compile-expr.h b/gcc/rust/backend/rust-compile-expr.h
index 4cc4dfc..43eff72 100644
--- a/gcc/rust/backend/rust-compile-expr.h
+++ b/gcc/rust/backend/rust-compile-expr.h
@@ -24,6 +24,7 @@
 #include "rust-compile-resolve-path.h"
 #include "rust-compile-block.h"
 #include "rust-compile-struct-field-expr.h"
+#include "rust-constexpr.h"
 
 namespace Rust {
 namespace Compile {
@@ -488,13 +489,10 @@ public:
     std::vector<tree> ctor_arguments;
     if (adt->is_enum ())
       {
-	HirId variant_id = variant->get_id ();
-	mpz_t val;
-	mpz_init_set_ui (val, variant_id);
-
-	tree t = TyTyResolveCompile::get_implicit_enumeral_node_type (ctx);
-	tree qualifier
-	  = double_int_to_tree (t, mpz_get_double_int (t, val, true));
+	HIR::Expr *discrim_expr = variant->get_discriminant ();
+	tree discrim_expr_node = CompileExpr::Compile (discrim_expr, ctx);
+	tree folded_discrim_expr = ConstCtx::fold (discrim_expr_node);
+	tree qualifier = folded_discrim_expr;
 
 	ctor_arguments.push_back (qualifier);
       }
diff --git a/gcc/rust/backend/rust-compile-pattern.cc b/gcc/rust/backend/rust-compile-pattern.cc
index b255dc6..d715c7c 100644
--- a/gcc/rust/backend/rust-compile-pattern.cc
+++ b/gcc/rust/backend/rust-compile-pattern.cc
@@ -48,33 +48,10 @@ CompilePatternCaseLabelExpr::visit (HIR::PathInExpression &pattern)
   ok = adt->lookup_variant_by_id (variant_id, &variant);
   rust_assert (ok);
 
-  tree case_low = error_mark_node;
-  if (variant->is_specified_discriminant_node ())
-    {
-      auto discrim_node = variant->get_discriminant_node ();
-      auto &discrim_expr = discrim_node->get_discriminant_expression ();
-
-      tree discrim_expr_node = CompileExpr::Compile (discrim_expr.get (), ctx);
-      tree folded_discrim_expr = ConstCtx::fold (discrim_expr_node);
-      case_low = folded_discrim_expr;
-    }
-  else
-    {
-      mpz_t disciminantl;
-      if (variant->get_variant_type () == TyTy::VariantDef::VariantType::NUM)
-	{
-	  mpz_init_set_ui (disciminantl, variant->get_discriminant ());
-	}
-      else
-	{
-	  HirId variant_id = variant->get_id ();
-	  mpz_init_set_ui (disciminantl, variant_id);
-	}
-
-      tree t = TyTyResolveCompile::get_implicit_enumeral_node_type (ctx);
-      case_low
-	= double_int_to_tree (t, mpz_get_double_int (t, disciminantl, true));
-    }
+  HIR::Expr *discrim_expr = variant->get_discriminant ();
+  tree discrim_expr_node = CompileExpr::Compile (discrim_expr, ctx);
+  tree folded_discrim_expr = ConstCtx::fold (discrim_expr_node);
+  tree case_low = folded_discrim_expr;
 
   case_label_expr
     = build_case_label (case_low, NULL_TREE, associated_case_label);
diff --git a/gcc/rust/backend/rust-compile-resolve-path.cc b/gcc/rust/backend/rust-compile-resolve-path.cc
index ddb6c91..c624046 100644
--- a/gcc/rust/backend/rust-compile-resolve-path.cc
+++ b/gcc/rust/backend/rust-compile-resolve-path.cc
@@ -86,8 +86,8 @@ ResolvePathRef::resolve (const HIR::PathIdentSegment &final_segment,
 				      &union_disriminator))
 	return ctx->get_backend ()->error_expression ();
 
-      // FIXME should really return error_mark_node and or rust_internal_error
-      // error_mark_node
+      // this can only be for discriminant variants the others are built up
+      // using call-expr or struct-init
       rust_assert (variant->get_variant_type ()
 		   == TyTy::VariantDef::VariantType::NUM);
 
@@ -95,24 +95,10 @@ ResolvePathRef::resolve (const HIR::PathIdentSegment &final_segment,
       tree compiled_adt_type = TyTyResolveCompile::compile (ctx, adt);
 
       // make the ctor for the union
-      tree qualifier = error_mark_node;
-      if (variant->is_specified_discriminant_node ())
-	{
-	  auto discrim_node = variant->get_discriminant_node ();
-	  auto &discrim_expr = discrim_node->get_discriminant_expression ();
-
-	  tree discrim_expr_node
-	    = CompileExpr::Compile (discrim_expr.get (), ctx);
-	  tree folded_discrim_expr = ConstCtx::fold (discrim_expr_node);
-	  qualifier = folded_discrim_expr;
-	}
-      else
-	{
-	  mpz_t val;
-	  mpz_init_set_ui (val, variant->get_discriminant ());
-	  tree t = TyTyResolveCompile::get_implicit_enumeral_node_type (ctx);
-	  qualifier = double_int_to_tree (t, mpz_get_double_int (t, val, true));
-	}
+      HIR::Expr *discrim_expr = variant->get_discriminant ();
+      tree discrim_expr_node = CompileExpr::Compile (discrim_expr, ctx);
+      tree folded_discrim_expr = ConstCtx::fold (discrim_expr_node);
+      tree qualifier = folded_discrim_expr;
 
       return ctx->get_backend ()->constructor_expression (compiled_adt_type,
 							  true, {qualifier},