From e19e30ed0e7853b06d53371ec272b51c79386e2b Mon Sep 17 00:00:00 2001
From: Owen Avery <powerboat9.gamer@gmail.com>
Date: Sat, 9 Aug 2025 19:01:55 -0400
Subject: [PATCH] Improve macro expansion for libcore

This should prevent issues like
https://github.com/Rust-GCC/gccrs/issues/3444 from affecting compilation
of libcore 1.49.

gcc/rust/ChangeLog:

	* ast/rust-expr.h (BorrowExpr::get_borrowed_expr_ptr): New
	member function.
	(ErrorPropagationExpr::get_propagating_expr_ptr): Likewise.
	(MethodCallExpr::get_receiver_expr_ptr): Likewise.
	(MatchExpr::get_scrutinee_expr_ptr): Likewise.
	* expand/rust-expand-visitor.cc (ExpandVisitor::visit): Improve
	handling of expression child nodes.
	* expand/rust-expand-visitor.h (ExpandVisitor::visit): Add
	overloads.

Signed-off-by: Owen Avery <powerboat9.gamer@gmail.com>
---
 gcc/rust/ast/rust-expr.h               | 24 ++++++++++++++++++++++++
 gcc/rust/expand/rust-expand-visitor.cc | 20 +++++++++++++++++---
 gcc/rust/expand/rust-expand-visitor.h  |  2 ++
 3 files changed, 43 insertions(+), 3 deletions(-)

diff --git a/gcc/rust/ast/rust-expr.h b/gcc/rust/ast/rust-expr.h
index 03cad86de3d0..2b8dead541b6 100644
--- a/gcc/rust/ast/rust-expr.h
+++ b/gcc/rust/ast/rust-expr.h
@@ -414,6 +414,12 @@ class BorrowExpr : public OperatorExpr
     return *main_or_left_expr;
   }
 
+  std::unique_ptr<Expr> &get_borrowed_expr_ptr ()
+  {
+    rust_assert (main_or_left_expr != nullptr);
+    return main_or_left_expr;
+  }
+
   bool has_borrow_expr () const { return main_or_left_expr != nullptr; }
 
   bool get_is_mut () const { return mutability == Mutability::Mut; }
@@ -488,6 +494,12 @@ class ErrorPropagationExpr : public OperatorExpr
     return *main_or_left_expr;
   }
 
+  std::unique_ptr<Expr> &get_propagating_expr_ptr ()
+  {
+    rust_assert (main_or_left_expr != nullptr);
+    return main_or_left_expr;
+  }
+
   Expr::Kind get_expr_kind () const override
   {
     return Expr::Kind::ErrorPropagation;
@@ -2293,6 +2305,12 @@ class MethodCallExpr : public ExprWithoutBlock
     return *receiver;
   }
 
+  std::unique_ptr<Expr> &get_receiver_expr_ptr ()
+  {
+    rust_assert (receiver != nullptr);
+    return receiver;
+  }
+
   const PathExprSegment &get_method_name () const { return method_name; }
   PathExprSegment &get_method_name () { return method_name; }
 
@@ -4892,6 +4910,12 @@ class MatchExpr : public ExprWithBlock
     return *branch_value;
   }
 
+  std::unique_ptr<Expr> &get_scrutinee_expr_ptr ()
+  {
+    rust_assert (branch_value != nullptr);
+    return branch_value;
+  }
+
   const std::vector<MatchCase> &get_match_cases () const { return match_arms; }
   std::vector<MatchCase> &get_match_cases () { return match_arms; }
 
diff --git a/gcc/rust/expand/rust-expand-visitor.cc b/gcc/rust/expand/rust-expand-visitor.cc
index 8f6e7faa0c45..cc90223666d4 100644
--- a/gcc/rust/expand/rust-expand-visitor.cc
+++ b/gcc/rust/expand/rust-expand-visitor.cc
@@ -541,10 +541,16 @@ void
 ExpandVisitor::visit (AST::MetaItemPathExpr &)
 {}
 
+void
+ExpandVisitor::visit (AST::BorrowExpr &expr)
+{
+  maybe_expand_expr (expr.get_borrowed_expr_ptr ());
+}
+
 void
 ExpandVisitor::visit (AST::ErrorPropagationExpr &expr)
 {
-  visit (expr.get_propagating_expr ());
+  maybe_expand_expr (expr.get_propagating_expr_ptr ());
 }
 
 void
@@ -588,6 +594,14 @@ ExpandVisitor::visit (AST::GroupedExpr &expr)
   maybe_expand_expr (expr.get_expr_in_parens_ptr ());
 }
 
+void
+ExpandVisitor::visit (AST::TupleExpr &expr)
+{
+  // TODO: expand as multiple expressions?
+  for (auto &elem : expr.get_tuple_elems ())
+    maybe_expand_expr (elem);
+}
+
 void
 ExpandVisitor::visit (AST::StructExprStruct &expr)
 {}
@@ -604,7 +618,7 @@ ExpandVisitor::visit (AST::CallExpr &expr)
 void
 ExpandVisitor::visit (AST::MethodCallExpr &expr)
 {
-  visit (expr.get_receiver_expr ());
+  maybe_expand_expr (expr.get_receiver_expr_ptr ());
 
   for (auto &param : expr.get_params ())
     maybe_expand_expr (param);
@@ -679,7 +693,7 @@ ExpandVisitor::visit (AST::IfLetExprConseqElse &expr)
 void
 ExpandVisitor::visit (AST::MatchExpr &expr)
 {
-  visit (expr.get_scrutinee_expr ());
+  maybe_expand_expr (expr.get_scrutinee_expr_ptr ());
 
   for (auto &match_case : expr.get_match_cases ())
     {
diff --git a/gcc/rust/expand/rust-expand-visitor.h b/gcc/rust/expand/rust-expand-visitor.h
index 845e10cfec78..b3e971f69009 100644
--- a/gcc/rust/expand/rust-expand-visitor.h
+++ b/gcc/rust/expand/rust-expand-visitor.h
@@ -210,6 +210,7 @@ class ExpandVisitor : public AST::DefaultASTVisitor
   void visit (AST::AttrInputMacro &) override;
   void visit (AST::MetaItemLitExpr &) override;
   void visit (AST::MetaItemPathExpr &) override;
+  void visit (AST::BorrowExpr &) override;
   void visit (AST::ErrorPropagationExpr &expr) override;
   void visit (AST::ArithmeticOrLogicalExpr &expr) override;
   void visit (AST::ComparisonExpr &expr) override;
@@ -217,6 +218,7 @@ class ExpandVisitor : public AST::DefaultASTVisitor
   void visit (AST::AssignmentExpr &expr) override;
   void visit (AST::CompoundAssignmentExpr &expr) override;
   void visit (AST::GroupedExpr &expr) override;
+  void visit (AST::TupleExpr &expr) override;
   void visit (AST::StructExprStruct &expr) override;
 
   void visit (AST::CallExpr &expr) override;