From cddb1f2d9f965aa6386a71369109edd61506118e Mon Sep 17 00:00:00 2001
From: Arthur Cohen <arthur.cohen@embecosm.com>
Date: Wed, 1 Feb 2023 11:40:13 +0100
Subject: parser: Allow parsing multiple reference types

The parser now recursively tries to parse a reference type after seeing
a `&` or `&&` token.

gcc/rust/ChangeLog:

	* parse/rust-parse-impl.h (Parser::parse_type): Handle double ampersan
	properly
	(Parser::parse_reference_type): Call into `parse_reference_type_inner`
	and wrap double reference types in another `AST::ReferenceType` node
	(Parser::parse_reference_type_inner): Add parsing implementation
	which does not care about the leading token (& or  &&)
	(Parser::parse_type_no_bounds): Handle double ampersand properly
	* parse/rust-parse.h: Declare `parse_reference_type_inner`

gcc/testsuite/ChangeLog:

	* rust/compile/multi_reference_type.rs: New test.
---
 gcc/rust/parse/rust-parse-impl.h | 33 +++++++++++++++++++++++++++------
 1 file changed, 27 insertions(+), 6 deletions(-)

(limited to 'gcc/rust/parse/rust-parse-impl.h')

diff --git a/gcc/rust/parse/rust-parse-impl.h b/gcc/rust/parse/rust-parse-impl.h
index c19fe9b..19743c6 100644
--- a/gcc/rust/parse/rust-parse-impl.h
+++ b/gcc/rust/parse/rust-parse-impl.h
@@ -9239,6 +9239,7 @@ Parser<ManagedTokenSource>::parse_type (bool save_errors)
       // raw pointer type
       return parse_raw_pointer_type ();
     case AMP: // does this also include AMP_AMP?
+    case LOGICAL_AND:
       // reference type
       return parse_reference_type ();
       case LIFETIME: {
@@ -9889,14 +9890,10 @@ Parser<ManagedTokenSource>::parse_bare_function_type (
 			       std::move (return_type), best_try_locus));
 }
 
-// Parses a reference type (mutable or immutable, with given lifetime).
 template <typename ManagedTokenSource>
 std::unique_ptr<AST::ReferenceType>
-Parser<ManagedTokenSource>::parse_reference_type ()
+Parser<ManagedTokenSource>::parse_reference_type_inner (Location locus)
 {
-  Location locus = lexer.peek_token ()->get_locus ();
-  skip_token (AMP);
-
   // parse optional lifetime
   AST::Lifetime lifetime = AST::Lifetime::error ();
   if (lexer.peek_token ()->get_id () == LIFETIME)
@@ -9935,6 +9932,29 @@ Parser<ManagedTokenSource>::parse_reference_type ()
 			    std::move (lifetime)));
 }
 
+// Parses a reference type (mutable or immutable, with given lifetime).
+template <typename ManagedTokenSource>
+std::unique_ptr<AST::ReferenceType>
+Parser<ManagedTokenSource>::parse_reference_type ()
+{
+  auto t = lexer.peek_token ();
+  auto locus = t->get_locus ();
+
+  switch (t->get_id ())
+    {
+    case AMP:
+      skip_token (AMP);
+      return parse_reference_type_inner (locus);
+    case LOGICAL_AND:
+      skip_token (LOGICAL_AND);
+      return std::unique_ptr<AST::ReferenceType> (
+	new AST::ReferenceType (false, parse_reference_type_inner (locus),
+				locus));
+    default:
+      gcc_unreachable ();
+    }
+}
+
 // Parses a raw (unsafe) pointer type.
 template <typename ManagedTokenSource>
 std::unique_ptr<AST::RawPointerType>
@@ -10082,7 +10102,8 @@ Parser<ManagedTokenSource>::parse_type_no_bounds ()
     case ASTERISK:
       // raw pointer type
       return parse_raw_pointer_type ();
-    case AMP: // does this also include AMP_AMP?
+    case AMP: // does this also include AMP_AMP? Yes! Which is... LOGICAL_AND?
+    case LOGICAL_AND:
       // reference type
       return parse_reference_type ();
     case LIFETIME:
-- 
cgit v1.1