ast: Add Kind::MACRO_INVOCATION and cleanup fatal errors in lowering

macro invocations

gcc/rust/ast/rust-ast.h

@@ -41,6 +41,7 @@ enum Kind
 {
   UNKNOWN,
   MACRO_RULES_DEFINITION,
+  MACRO_INVOCATION,
 };
 
 // Abstract base class for all AST elements
@@ -900,7 +901,7 @@ protected:
 class ExprWithoutBlock;
 
 // Base expression AST node - abstract
-class Expr
+class Expr : public Node
 {
 public:
   // Unique pointer custom clone function
@@ -1073,7 +1074,7 @@ protected:
 class TraitBound;
 
 // Base class for types as represented in AST - abstract
-class Type
+class Type : public Node
 {
 public:
   // Unique pointer custom clone function

gcc/rust/ast/rust-macro.h

@@ -507,6 +507,8 @@ public:
     return ExprWithoutBlock::get_node_id ();
   }
 
+  Kind get_ast_kind () const override { return Kind::MACRO_INVOCATION; }
+
   NodeId get_macro_node_id () const { return node_id; }
 
   MacroInvocData &get_invoc_data () { return invoc_data; }

gcc/rust/hir/rust-ast-lower-expr.h

@@ -100,14 +100,6 @@ public:
     return resolver.translated;
   }
 
-  void visit (AST::MacroInvocation &expr) override
-  {
-    rust_fatal_error (
-      expr.get_locus (),
-      "macro expansion failed: No macro invocation should get lowered to HIR "
-      "as they should disappear during expansion");
-  }
-
   void visit (AST::TupleIndexExpr &expr) override
   {
     HIR::Expr *tuple_expr

gcc/rust/hir/rust-ast-lower-implitem.h

@@ -52,14 +52,6 @@ public:
     return resolver.translated;
   }
 
-  void visit (AST::MacroInvocation &invoc) override
-  {
-    rust_fatal_error (
-      invoc.get_locus (),
-      "macro expansion failed: No macro invocation should get lowered to HIR "
-      "as they should disappear during expansion");
-  }
-
   void visit (AST::TypeAlias &alias) override
   {
     std::vector<std::unique_ptr<HIR::WhereClauseItem> > where_clause_items;
@@ -316,14 +308,6 @@ public:
     return resolver.translated;
   }
 
-  void visit (AST::MacroInvocation &invoc) override
-  {
-    rust_fatal_error (
-      invoc.get_locus (),
-      "macro expansion failed: No macro invocation should get lowered to HIR "
-      "as they should disappear during expansion");
-  }
-
   void visit (AST::TraitItemFunc &func) override
   {
     AST::TraitFunctionDecl &ref = func.get_trait_function_decl ();

gcc/rust/hir/rust-ast-lower-item.h

@@ -51,14 +51,6 @@ public:
     return resolver.translated;
   }
 
-  void visit (AST::MacroInvocation &invoc) override
-  {
-    rust_fatal_error (
-      invoc.get_locus (),
-      "macro expansion failed: No macro invocation should get lowered to HIR "
-      "as they should disappear during expansion");
-  }
-
   void visit (AST::Module &module) override
   {
     auto crate_num = mappings->get_current_crate ();

gcc/rust/hir/rust-ast-lower-stmt.h

@@ -45,14 +45,6 @@ public:
     return resolver.translated;
   }
 
-  void visit (AST::MacroInvocation &invoc) override
-  {
-    rust_fatal_error (
-      invoc.get_locus (),
-      "macro expansion failed: No macro invocation should get lowered to HIR "
-      "as they should disappear during expansion");
-  }
-
   void visit (AST::ExprStmtWithBlock &stmt) override
   {
     HIR::ExprWithBlock *expr

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

@@ -70,6 +70,13 @@ ASTLoweringBlock::visit (AST::BlockExpr &expr)
       if (s->get_ast_kind () == AST::Kind::MACRO_RULES_DEFINITION)
 	continue;
 
+      if (s->get_ast_kind () == AST::Kind::MACRO_INVOCATION)
+	rust_fatal_error (
+	  s->get_locus (),
+	  "macro invocations should not get lowered to HIR - At "
+	  "this point in "
+	  "the pipeline, they should all have been expanded");
+
       if (block_did_terminate)
 	rust_warning_at (s->get_locus (), 0, "unreachable statement");