gccrs: Improve GroupedPattern lowering

gcc/rust/ChangeLog:

	* hir/rust-ast-lower-pattern.cc
	(ASTLoweringPattern::visit): Lower AST::GroupedPattern to its inner pattern.

Signed-off-by: Owen Avery <powerboat9.gamer@gmail.com>

Author: powerboat9

gcc/rust/hir/rust-ast-lower-pattern.cc

@@ -246,17 +246,7 @@ ASTLoweringPattern::visit (AST::RangePattern &pattern)
 void
 ASTLoweringPattern::visit (AST::GroupedPattern &pattern)
 {
-  auto crate_num = mappings->get_current_crate ();
-  Analysis::NodeMapping mapping (crate_num, pattern.get_node_id (),
-				 mappings->get_next_hir_id (crate_num),
-				 UNKNOWN_LOCAL_DEFID);
-
-  HIR::Pattern *inner
-    = ASTLoweringPattern::translate (pattern.get_pattern_in_parens ().get ());
-
-  translated
-    = new HIR::GroupedPattern (mapping, std::unique_ptr<HIR::Pattern> (inner),
-			       pattern.get_locus ());
+  pattern.get_pattern_in_parens ()->accept_vis (*this);
 }
 
 } // namespace HIR