Decouple the HIR::OperatorExpr from resolving operator overloads

This means we can reuse the same code for operations that are not
HIR::OperatorExpr's such as ArrayIndexExpr which can resolve to
core::ops::index lang items.

Author: philberty

gcc/rust/backend/rust-compile-expr.cc

@@ -790,7 +790,7 @@ CompileExpr::resolve_method_address (TyTy::FnType *fntype, HirId ref,
 
 tree
 CompileExpr::resolve_operator_overload (
-  Analysis::RustLangItem::ItemType lang_item_type, HIR::OperatorExpr &expr,
+  Analysis::RustLangItem::ItemType lang_item_type, HIR::OperatorExprMeta expr,
   tree lhs, tree rhs, HIR::Expr *lhs_expr, HIR::Expr *rhs_expr)
 {
   TyTy::FnType *fntype;

gcc/rust/backend/rust-compile-expr.h

@@ -799,7 +799,7 @@ class CompileExpr : public HIRCompileBase
 
   tree
   resolve_operator_overload (Analysis::RustLangItem::ItemType lang_item_type,
-			     HIR::OperatorExpr &expr, tree lhs, tree rhs,
+			     HIR::OperatorExprMeta expr, tree lhs, tree rhs,
 			     HIR::Expr *lhs_expr, HIR::Expr *rhs_expr);
 
   tree compile_bool_literal (const HIR::LiteralExpr &expr,

gcc/rust/hir/tree/rust-hir-expr.h

@@ -4029,6 +4029,36 @@ class AsyncBlockExpr : public ExprWithBlock
     return new AsyncBlockExpr (*this);
   }
 };
+
+// this is a utility helper class for type-checking and code-generation
+class OperatorExprMeta
+{
+public:
+  OperatorExprMeta (HIR::CompoundAssignmentExpr &expr)
+    : node_mappings (expr.get_mappings ()), locus (expr.get_locus ())
+  {}
+
+  OperatorExprMeta (HIR::ArithmeticOrLogicalExpr &expr)
+    : node_mappings (expr.get_mappings ()), locus (expr.get_locus ())
+  {}
+
+  OperatorExprMeta (HIR::NegationExpr &expr)
+    : node_mappings (expr.get_mappings ()), locus (expr.get_locus ())
+  {}
+
+  OperatorExprMeta (HIR::DereferenceExpr &expr)
+    : node_mappings (expr.get_mappings ()), locus (expr.get_locus ())
+  {}
+
+  const Analysis::NodeMapping &get_mappings () const { return node_mappings; }
+
+  Location get_locus () const { return locus; }
+
+private:
+  const Analysis::NodeMapping node_mappings;
+  Location locus;
+};
+
 } // namespace HIR
 } // namespace Rust
 

gcc/rust/typecheck/rust-hir-type-check-expr.cc

@@ -288,7 +288,7 @@ TypeCheckExpr::visit (HIR::ArrayIndexExpr &expr)
 
 bool
 TypeCheckExpr::resolve_operator_overload (
-  Analysis::RustLangItem::ItemType lang_item_type, HIR::OperatorExpr &expr,
+  Analysis::RustLangItem::ItemType lang_item_type, HIR::OperatorExprMeta expr,
   TyTy::BaseType *lhs, TyTy::BaseType *rhs)
 {
   // look up lang item for arithmetic type

gcc/rust/typecheck/rust-hir-type-check-expr.h

@@ -1239,7 +1239,7 @@ class TypeCheckExpr : public TypeCheckBase
 protected:
   bool
   resolve_operator_overload (Analysis::RustLangItem::ItemType lang_item_type,
-			     HIR::OperatorExpr &expr, TyTy::BaseType *lhs,
+			     HIR::OperatorExprMeta expr, TyTy::BaseType *lhs,
 			     TyTy::BaseType *rhs);
 
 private: