gccrs: Fix parsing of block expressions followed by `.`

`{ ... }.f;` is parsed as a single statement in rust. This means that we can't
determine whether an expression statement will need a semicolon terminator
until we finish parsing it. To handle this we change expression parsing to
check for this case by inspecting the expression returned from null_denotation
and looking ahead for a `.` or `?` token.

gcc/rust/ChangeLog:

	* ast/rust-ast.h (Expr::as_expr_without_block): Remove.
	(Expr::set_outer_attrs): Make public in base class.
	* expand/rust-macro-expand.cc:
	Add fixme comment for pre-existing bug.
	* hir/tree/rust-hir.h: Remove Expr::as_expr_without_block.
	* parse/rust-parse-impl.h (Parser::parse_lifetime): Use lifetime_from_token.
	(Parser::lifetime_from_token): New method.
	(Parser::null_denotation): Handle labelled loop expressions and for loop expressions.
	(Parser::parse_loop_label): Make initial token a parameter.
	(Parser::parse_labelled_loop_expr): Likewise.
	(Parser::parse_for_loop_expr): Allow FOR token to already be skipped.
	(Parser::parse_expr): Handle expr_can_be_stmt.
	(Parser::parse_expr_with_block): Remove.
	(Parser::parse_expr_stmt_with_block): Remove.
	(Parser::parse_expr_stmt_without_block): Remove.
	(Parser::parse_expr_without_block): Remove.
	(Parser::parse_stmt_or_expr_with_block): Remove.
	(Parser::parse_expr_stmt): Use parse_expr directly.
	(Parser::parse_match_expr): Likewise.
	(Parser::parse_stmt): Use parse_expr_stmt in more cases.
	(Parser::parse_stmt_or_expr):
	Rename from parse_stmt_or_expr_without_block, use parse_expr directly.
	(Parser::parse_block_expr): Update error message.
	* parse/rust-parse.h: Update declarations.

gcc/testsuite/ChangeLog:

	* rust/compile/for_expr.rs: New test.
	* rust/compile/issue-407-2.rs: Update compiler output.
	* rust/compile/issue-407.rs: Update compiler output.
	* rust/compile/issue-867.rs: Update compiler output.
	* rust/compile/issue-2189.rs: New test.
	* rust/compile/macro_call_statement.rs: New test.
	* rust/compile/stmt_with_block_dot.rs: New test.
	* rust/compile/torture/loop8.rs: New test.

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

1 files changed, 5 insertions, 17 deletions

diff --git a/gcc/rust/parse/rust-parse.h b/gcc/rust/parse/rust-parse.h
index a092290..1e7e526 100644
--- a/gcc/rust/parse/rust-parse.h
+++ b/gcc/rust/parse/rust-parse.h
@@ -276,6 +276,7 @@ private:
   template <typename EndTokenPred>
   std::vector<AST::Lifetime> parse_lifetime_bounds (EndTokenPred is_end_token);
   AST::Lifetime parse_lifetime ();
+  AST::Lifetime lifetime_from_token (const_TokenPtr tok);
   std::unique_ptr<AST::ExternalTypeItem>
   parse_external_type_item (AST::Visibility vis, AST::AttrVec outer_attrs);
   std::unique_ptr<AST::TypeAlias> parse_type_alias (AST::Visibility vis,
@@ -531,13 +532,6 @@ private:
     AST::AttrVec outer_attrs,
     ParseRestrictions restrictions = ParseRestrictions ());
 
-  // Expression-related (non-Pratt parsed)
-  std::unique_ptr<AST::ExprWithBlock>
-  parse_expr_with_block (AST::AttrVec outer_attrs);
-  std::unique_ptr<AST::ExprWithoutBlock>
-  parse_expr_without_block (AST::AttrVec outer_attrs = AST::AttrVec (),
-			    ParseRestrictions restrictions
-			    = ParseRestrictions ());
   // When given a pratt_parsed_loc, use it as the location of the
   // first token parsed in the expression (the parsing of that first
   // token should be skipped).
@@ -569,8 +563,9 @@ private:
   std::vector<std::unique_ptr<AST::Pattern> >
   parse_match_arm_patterns (TokenId end_token_id);
   std::unique_ptr<AST::BaseLoopExpr>
-  parse_labelled_loop_expr (AST::AttrVec outer_attrs = AST::AttrVec ());
-  AST::LoopLabel parse_loop_label ();
+  parse_labelled_loop_expr (const_TokenPtr tok,
+			    AST::AttrVec outer_attrs = AST::AttrVec ());
+  AST::LoopLabel parse_loop_label (const_TokenPtr tok);
   std::unique_ptr<AST::AsyncBlockExpr>
   parse_async_block_expr (AST::AttrVec outer_attrs = AST::AttrVec ());
   std::unique_ptr<AST::GroupedExpr> parse_grouped_expr (AST::AttrVec outer_attrs
@@ -637,14 +632,7 @@ private:
   std::unique_ptr<AST::ExprStmt> parse_expr_stmt (AST::AttrVec outer_attrs,
 						  ParseRestrictions restrictions
 						  = ParseRestrictions ());
-  std::unique_ptr<AST::ExprStmt>
-  parse_expr_stmt_with_block (AST::AttrVec outer_attrs);
-  std::unique_ptr<AST::ExprStmt>
-  parse_expr_stmt_without_block (AST::AttrVec outer_attrs,
-				 ParseRestrictions restrictions
-				 = ParseRestrictions ());
-  ExprOrStmt parse_stmt_or_expr_without_block ();
-  ExprOrStmt parse_stmt_or_expr_with_block (AST::AttrVec outer_attrs);
+  ExprOrStmt parse_stmt_or_expr ();
   ExprOrStmt parse_macro_invocation_maybe_semi (AST::AttrVec outer_attrs);
   ExprOrStmt parse_path_based_stmt_or_expr (AST::AttrVec outer_attrs);