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, 46 insertions, 3 deletions

diff --git a/gcc/rust/backend/rust-compile-var-decl.h b/gcc/rust/backend/rust-compile-var-decl.h
index c431edd..2dab39e 100644
--- a/gcc/rust/backend/rust-compile-var-decl.h
+++ b/gcc/rust/backend/rust-compile-var-decl.h
@@ -20,13 +20,17 @@
 #define RUST_COMPILE_VAR_DECL
 
 #include "rust-compile-base.h"
+#include "rust-hir-visitor.h"
 
 namespace Rust {
 namespace Compile {
 
-class CompileVarDecl : public HIRCompileBase
+class CompileVarDecl : public HIRCompileBase,
+		       public HIR::HIRPatternVisitor,
+		       public HIR::HIRStmtVisitor
 {
-  using Rust::Compile::HIRCompileBase::visit;
+  using HIR::HIRPatternVisitor::visit;
+  using HIR::HIRStmtVisitor::visit;
 
 public:
   static ::Bvariable *compile (tree fndecl, HIR::Stmt *stmt, Context *ctx)
@@ -47,7 +51,8 @@ public:
     rust_assert (ok);
 
     translated_type = TyTyResolveCompile::compile (ctx, resolved_type);
-    stmt.get_pattern ()->accept_vis (*this);
+    stmt.get_pattern ()->accept_vis (
+      static_cast<HIR::HIRPatternVisitor &> (*this));
   }
 
   void visit (HIR::IdentifierPattern &pattern) override
@@ -70,6 +75,44 @@ public:
 					     NULL /*decl_var*/, locus);
   }
 
+  // Empty visit for unused Pattern HIR nodes.
+  void visit (HIR::GroupedPattern &) override {}
+  void visit (HIR::LiteralPattern &) override {}
+  void visit (HIR::PathInExpression &) override {}
+  void visit (HIR::QualifiedPathInExpression &) 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 {}
+
+  // Empty visit for unused Stmt HIR nodes.
+  void visit (HIR::EnumItemTuple &) override {}
+  void visit (HIR::EnumItemStruct &) override {}
+  void visit (HIR::EnumItem &item) override {}
+  void visit (HIR::TupleStruct &tuple_struct) override {}
+  void visit (HIR::EnumItemDiscriminant &) override {}
+  void visit (HIR::TypePathSegmentFunction &segment) override {}
+  void visit (HIR::TypePath &path) override {}
+  void visit (HIR::QualifiedPathInType &path) override {}
+  void visit (HIR::Module &module) override {}
+  void visit (HIR::ExternCrate &crate) override {}
+  void visit (HIR::UseDeclaration &use_decl) override {}
+  void visit (HIR::Function &function) override {}
+  void visit (HIR::TypeAlias &type_alias) override {}
+  void visit (HIR::StructStruct &struct_item) override {}
+  void visit (HIR::Enum &enum_item) override {}
+  void visit (HIR::Union &union_item) override {}
+  void visit (HIR::ConstantItem &const_item) override {}
+  void visit (HIR::StaticItem &static_item) override {}
+  void visit (HIR::Trait &trait) override {}
+  void visit (HIR::ImplBlock &impl) override {}
+  void visit (HIR::ExternBlock &block) override {}
+  void visit (HIR::EmptyStmt &stmt) override {}
+  void visit (HIR::ExprStmtWithoutBlock &stmt) override {}
+  void visit (HIR::ExprStmtWithBlock &stmt) override {}
+
 private:
   CompileVarDecl (Context *ctx, tree fndecl)
     : HIRCompileBase (ctx), fndecl (fndecl), translated_type (error_mark_node),