HIR Visitor refactoring

This change split the single HIR visitor in smaller abstract ones:
- Stmt
- VisItem
- Pattern
- ExternalItem
- Impl
- Type
- Expression

Instead of providing a Base class with empty visit() methods, they are kept
abstract to avoid the case where a missing visit() is silently ignored:
implementors must explicitely override all visit.

There is also a FullVisitor that covers all HIR nodes and also provides a Base
class with empty behavior.

fixes #825

Signed-off-by: Marc Poulhiès <dkm@kataplop.net>

1 files changed, 13 insertions, 5 deletions

diff --git a/gcc/rust/backend/rust-compile-resolve-path.h b/gcc/rust/backend/rust-compile-resolve-path.h
index 9c9d7c5..37dec0b 100644
--- a/gcc/rust/backend/rust-compile-resolve-path.h
+++ b/gcc/rust/backend/rust-compile-resolve-path.h
@@ -25,10 +25,8 @@
 namespace Rust {
 namespace Compile {
 
-class ResolvePathRef : public HIRCompileBase
+class ResolvePathRef : public HIRCompileBase, public HIR::HIRPatternVisitor
 {
-  using Rust::Compile::HIRCompileBase::visit;
-
 public:
   static tree Compile (HIR::QualifiedPathInExpression &expr, Context *ctx)
   {
@@ -45,10 +43,20 @@ public:
   }
 
   void visit (HIR::PathInExpression &expr) override;
-
   void visit (HIR::QualifiedPathInExpression &expr) override;
 
-private:
+  // Empty visit for unused Pattern HIR nodes.
+  void visit (HIR::GroupedPattern &) override {}
+  void visit (HIR::IdentifierPattern &) override {}
+  void visit (HIR::LiteralPattern &) override {}
+  void visit (HIR::RangePattern &) override {}
+  void visit (HIR::ReferencePattern &) override {}
+  void visit (HIR::SlicePattern &) override {}
+  void visit (HIR::StructPattern &) override {}
+  void visit (HIR::TuplePattern &) override {}
+  void visit (HIR::TupleStructPattern &) override {}
+  void visit (HIR::WildcardPattern &) override {}
+
   ResolvePathRef (Context *ctx)
     : HIRCompileBase (ctx), resolved (error_mark_node)
   {}