Desugar HIR::IdentifierExpr into HIR::PathInExpression

This completly removes the HIR::IdentifierExpr and unifies how we handle
generics in general. There was a hack from last year that did not infer
generic arguments on IdentifierExpr's which leads to a type inferencing
behvaiour mismatch which was becoming difficult to debug. This simplifies
everything.

The changes to the test case reflect making our code more compliant to
real rustc apart from compile/traits3.rs which will be fixed as part of the
refactoring effort going on in the type system.

Fixes #1456

1 files changed, 15 insertions, 0 deletions

diff --git a/gcc/rust/backend/rust-compile-resolve-path.cc b/gcc/rust/backend/rust-compile-resolve-path.cc
index 8c1b7ef..f799445 100644
--- a/gcc/rust/backend/rust-compile-resolve-path.cc
+++ b/gcc/rust/backend/rust-compile-resolve-path.cc
@@ -64,6 +64,13 @@ ResolvePathRef::resolve (const HIR::PathIdentSegment &final_segment,
 	return error_mark_node;
 
       TyTy::ADTType *adt = static_cast<TyTy::ADTType *> (lookup);
+
+      // it might be a unit-struct
+      if (adt->is_unit ())
+	{
+	  return ctx->get_backend ()->unit_expression ();
+	}
+
       if (!adt->is_enum ())
 	return error_mark_node;
 
@@ -121,6 +128,14 @@ ResolvePathRef::resolve (const HIR::PathIdentSegment &final_segment,
       return ctx->get_backend ()->var_expression (var, expr_locus);
     }
 
+  // might be a match pattern binding
+  tree binding = error_mark_node;
+  if (ctx->lookup_pattern_binding (ref, &binding))
+    {
+      TREE_USED (binding) = 1;
+      return binding;
+    }
+
   // it might be a function call
   if (lookup->get_kind () == TyTy::TypeKind::FNDEF)
     {