gccrs: Parse semicolons in more cases for statement macros

gcc/rust/ChangeLog:

	* ast/rust-ast.h (MacroInvocation::add_semicolon): New method.
	* ast/rust-macro.h (MacroInvocation::add_semicolon): Add override.
	* ast/rust-stmt.h (ExprStmt::add_semicolon): Add override.
	* expand/rust-macro-expand.cc (parse_many): Pass enum by value.
	(transcribe_many_stmts): Parse statements with semicolons.
	* parse/rust-parse-impl.h (Parser::parse_let_stmt):
	Work around lack of NT tokens.
	(Parser::parse_expr_stmt): Handle statements at end of macro expansions.
	* parse/rust-parse.h (struct ParseRestrictions): Additional flag.

gcc/testsuite/ChangeLog:

	* rust/compile/macro53.rs: New test.

Signed-off-by: Matthew Jasper <mjjasper1@gmail.com>

2 files changed, 34 insertions, 6 deletions

diff --git a/gcc/rust/parse/rust-parse-impl.h b/gcc/rust/parse/rust-parse-impl.h
index d6b045b..c9dbee2 100644
--- a/gcc/rust/parse/rust-parse-impl.h
+++ b/gcc/rust/parse/rust-parse-impl.h
@@ -6348,8 +6348,16 @@ Parser<ManagedTokenSource>::parse_let_stmt (AST::AttrVec outer_attrs,
     }
 
   if (restrictions.consume_semi)
-    if (!skip_token (SEMICOLON))
-      return nullptr;
+    {
+      // `stmt` macro variables are parsed without a semicolon, but should be
+      // parsed as a full statement when interpolated. This should be handled
+      // by having the interpolated statement be distinguishable from normal
+      // tokens, e.g. by NT tokens.
+      if (restrictions.allow_close_after_expr_stmt)
+	maybe_skip_token (SEMICOLON);
+      else if (!skip_token (SEMICOLON))
+	return nullptr;
+    }
 
   return std::unique_ptr<AST::LetStmt> (
     new AST::LetStmt (std::move (pattern), std::move (expr), std::move (type),
@@ -7289,10 +7297,27 @@ Parser<ManagedTokenSource>::parse_expr_stmt (AST::AttrVec outer_attrs,
 
   if (restrictions.consume_semi)
     {
-      if (skip_token (SEMICOLON))
-	has_semi = true;
-      else if (expr->is_expr_without_block ())
-	return nullptr;
+      if (maybe_skip_token (SEMICOLON))
+	{
+	  has_semi = true;
+	}
+      else if (!expr->is_expr_without_block ())
+	{
+	  if (restrictions.allow_close_after_expr_stmt)
+	    {
+	      TokenId id = lexer.peek_token ()->get_id ();
+	      if (id != RIGHT_PAREN && id != RIGHT_CURLY && id != RIGHT_SQUARE)
+		{
+		  expect_token (SEMICOLON);
+		  return nullptr;
+		}
+	    }
+	  else
+	    {
+	      expect_token (SEMICOLON);
+	      return nullptr;
+	    }
+	}
     }
 
   return std::unique_ptr<AST::ExprStmt> (
diff --git a/gcc/rust/parse/rust-parse.h b/gcc/rust/parse/rust-parse.h
index 315d3fc..74313df 100644
--- a/gcc/rust/parse/rust-parse.h
+++ b/gcc/rust/parse/rust-parse.h
@@ -87,6 +87,9 @@ struct ParseRestrictions
   bool expr_can_be_null = false;
   bool expr_can_be_stmt = false;
   bool consume_semi = true;
+  /* Macro invocations that are statements can expand without a semicolon after
+   * the final statement, if it's an expression statement. */
+  bool allow_close_after_expr_stmt = false;
 };
 
 // Parser implementation for gccrs.