From cb9998216d76ccc62b45fcf01b3a0928a026f7ed Mon Sep 17 00:00:00 2001
From: Philip Herron <philip.herron@embecosm.com>
Date: Tue, 9 Feb 2021 15:28:03 +0000
Subject: Fix parse of LoopExpr as part of a normal expression

For example this fixes the form of: let x = loop { ... };

Fixes #219
---
 gcc/rust/parse/rust-parse-impl.h | 29 ++++++++++++++++++++++++-----
 gcc/rust/parse/rust-parse.h      |  7 +++----
 2 files changed, 27 insertions(+), 9 deletions(-)

(limited to 'gcc')

diff --git a/gcc/rust/parse/rust-parse-impl.h b/gcc/rust/parse/rust-parse-impl.h
index 277cd8b..d391304 100644
--- a/gcc/rust/parse/rust-parse-impl.h
+++ b/gcc/rust/parse/rust-parse-impl.h
@@ -7827,14 +7827,30 @@ Parser<ManagedTokenSource>::parse_if_let_expr (
 template <typename ManagedTokenSource>
 std::unique_ptr<AST::LoopExpr>
 Parser<ManagedTokenSource>::parse_loop_expr (
-  std::vector<AST::Attribute> outer_attrs, AST::LoopLabel label)
+  std::vector<AST::Attribute> outer_attrs, AST::LoopLabel label,
+  bool pratt_parse)
 {
   Location locus = Linemap::unknown_location ();
-  if (label.is_error ())
-    locus = lexer.peek_token ()->get_locus ();
+  if (!pratt_parse)
+    {
+      if (label.is_error ())
+	locus = lexer.peek_token ()->get_locus ();
+      else
+	locus = label.get_locus ();
+
+      if (!skip_token (LOOP))
+	{
+	  skip_after_end_block ();
+	  return nullptr;
+	}
+    }
   else
-    locus = label.get_locus ();
-  skip_token (LOOP);
+    {
+      if (label.is_error ())
+	locus = lexer.peek_token ()->get_locus () - 1;
+      else
+	locus = label.get_locus ();
+    }
 
   // parse loop body, which is required
   std::unique_ptr<AST::BlockExpr> loop_body = parse_block_expr ();
@@ -12435,6 +12451,9 @@ Parser<ManagedTokenSource>::null_denotation (
 	  // if expr
 	  return parse_if_expr (std::move (outer_attrs), true);
 	}
+    case LOOP:
+      return parse_loop_expr (std::move (outer_attrs), AST::LoopLabel::error (),
+			      true);
     case MATCH_TOK:
       // also an expression with block
       return parse_match_expr (std::move (outer_attrs), true);
diff --git a/gcc/rust/parse/rust-parse.h b/gcc/rust/parse/rust-parse.h
index b811c77..873b55e9 100644
--- a/gcc/rust/parse/rust-parse.h
+++ b/gcc/rust/parse/rust-parse.h
@@ -500,10 +500,9 @@ private:
   parse_if_let_expr (std::vector<AST::Attribute> outer_attrs
 		     = std::vector<AST::Attribute> (),
 		     bool pratt_parse = false);
-  std::unique_ptr<AST::LoopExpr>
-  parse_loop_expr (std::vector<AST::Attribute> outer_attrs
-		   = std::vector<AST::Attribute> (),
-		   AST::LoopLabel label = AST::LoopLabel::error ());
+  std::unique_ptr<AST::LoopExpr> parse_loop_expr (
+    std::vector<AST::Attribute> outer_attrs = std::vector<AST::Attribute> (),
+    AST::LoopLabel label = AST::LoopLabel::error (), bool pratt_parse = false);
   std::unique_ptr<AST::WhileLoopExpr>
   parse_while_loop_expr (std::vector<AST::Attribute> outer_attrs
 			 = std::vector<AST::Attribute> (),
-- 
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