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, 0 insertions, 11 deletions

diff --git a/gcc/rust/hir/tree/rust-hir.h b/gcc/rust/hir/tree/rust-hir.h
index 31f1494..0258f5f 100644
--- a/gcc/rust/hir/tree/rust-hir.h
+++ b/gcc/rust/hir/tree/rust-hir.h
@@ -288,10 +288,6 @@ public:
     return std::unique_ptr<Expr> (clone_expr_impl ());
   }
 
-  /* HACK: downcasting without dynamic_cast (if possible) via polymorphism -
-   * overrided in subclasses of ExprWithoutBlock */
-  virtual ExprWithoutBlock *as_expr_without_block () const { return nullptr; }
-
   // TODO: make pure virtual if move out outer attributes to derived classes
   virtual std::string as_string () const;
 
@@ -354,13 +350,6 @@ public:
     return std::unique_ptr<ExprWithoutBlock> (clone_expr_without_block_impl ());
   }
 
-  /* downcasting hack from expr to use pratt parsing with
-   * parse_expr_without_block */
-  ExprWithoutBlock *as_expr_without_block () const override
-  {
-    return clone_expr_without_block_impl ();
-  }
-
   BlockType get_block_expr_type () const final override
   {
     return BlockType::WITHOUT_BLOCK;