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, 19 insertions, 5 deletions

diff --git a/gcc/rust/backend/rust-compile-expr.h b/gcc/rust/backend/rust-compile-expr.h
index f2b4df8..3cc51d4 100644
--- a/gcc/rust/backend/rust-compile-expr.h
+++ b/gcc/rust/backend/rust-compile-expr.h
@@ -29,10 +29,8 @@
 namespace Rust {
 namespace Compile {
 
-class CompileExpr : public HIRCompileBase
+class CompileExpr : public HIRCompileBase, public HIR::HIRExpressionVisitor
 {
-  using Rust::Compile::HIRCompileBase::visit;
-
 public:
   static tree Compile (HIR::Expr *expr, Context *ctx)
   {
@@ -769,9 +767,7 @@ public:
   }
 
   void visit (HIR::BorrowExpr &expr) override;
-
   void visit (HIR::DereferenceExpr &expr) override;
-
   void visit (HIR::MatchExpr &expr) override;
 
   void visit (HIR::RangeFromToExpr &expr) override;
@@ -784,6 +780,24 @@ public:
 
   void visit (HIR::RangeFromToInclExpr &expr) override;
 
+  // Empty visit for unused Expression HIR nodes.
+  void visit (HIR::ClosureExprInner &) override {}
+  void visit (HIR::ClosureExprInnerTyped &) override {}
+  void visit (HIR::StructExprFieldIdentifier &) override {}
+  void visit (HIR::StructExprFieldIdentifierValue &) override {}
+  void visit (HIR::StructExprFieldIndexValue &) override {}
+  void visit (HIR::ErrorPropagationExpr &) override {}
+  void visit (HIR::RangeToInclExpr &) override {}
+  void visit (HIR::WhileLetLoopExpr &) override {}
+  void visit (HIR::ForLoopExpr &) override {}
+  void visit (HIR::IfExprConseqIfLet &) override {}
+  void visit (HIR::IfLetExpr &) override {}
+  void visit (HIR::IfLetExprConseqElse &) override {}
+  void visit (HIR::IfLetExprConseqIf &) override {}
+  void visit (HIR::IfLetExprConseqIfLet &) override {}
+  void visit (HIR::AwaitExpr &) override {}
+  void visit (HIR::AsyncBlockExpr &) override {}
+
 protected:
   tree compile_dyn_dispatch_call (const TyTy::DynamicObjectType *dyn,
 				  TyTy::BaseType *receiver,