[gcc r14-8153] gccrs: Fix float lexing and tuple index disambiguation

[gcc r14-8153] gccrs: Fix float lexing and tuple index disambiguation

[Arthur Cohen]

https://gcc.gnu.org/g:348f028fc2957d13e828030119938b8fccb00fc3

commit r14-8153-g348f028fc2957d13e828030119938b8fccb00fc3
Author: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>
Date:   Tue Oct 31 15:23:45 2023 +0100

    gccrs: Fix float lexing and tuple index disambiguation
    
    When a float has a floating point but no value after it, a zero was added
    this lead to errors when trying to disambiguate a float into a tuple
    index.
    
    gcc/rust/ChangeLog:
    
            * lex/rust-lex.cc (Lexer::parse_decimal_int_or_float): Remove
            additional zero after empty floating point.
            * parse/rust-parse-impl.h (Parser::left_denotation): Handle float with
            empty floating point.
    
    Signed-off-by: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>

Diff:
---
 gcc/rust/lex/rust-lex.cc         |  3 ---
 gcc/rust/parse/rust-parse-impl.h | 18 ++++++++++++------
 2 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/gcc/rust/lex/rust-lex.cc b/gcc/rust/lex/rust-lex.cc
index b78565ec3a5..107dbad2ff9 100644
--- a/gcc/rust/lex/rust-lex.cc
+++ b/gcc/rust/lex/rust-lex.cc
@@ -2351,9 +2351,6 @@ Lexer::parse_decimal_int_or_float (location_t loc)
       current_char = peek_input ();
       length++;
 
-      // add a '0' after the . to prevent ambiguity
-      str += '0';
-
       // type hint not allowed
 
       current_column += length;
diff --git a/gcc/rust/parse/rust-parse-impl.h b/gcc/rust/parse/rust-parse-impl.h
index 0e50c9eb17a..fd648c53e14 100644
--- a/gcc/rust/parse/rust-parse-impl.h
+++ b/gcc/rust/parse/rust-parse-impl.h
@@ -12892,12 +12892,18 @@ Parser<ManagedTokenSource>::left_denotation (const_TokenPtr tok,
 	    auto dot_pos = str.find (".");
 	    auto prefix = str.substr (0, dot_pos);
 	    auto suffix = str.substr (dot_pos + 1);
-	    lexer.split_current_token (
-	      {Token::make_int (current_loc, std::move (prefix),
-				CORETYPE_PURE_DECIMAL),
-	       Token::make (DOT, current_loc + 1),
-	       Token::make_int (current_loc + 2, std::move (suffix),
-				CORETYPE_PURE_DECIMAL)});
+	    if (dot_pos == str.size () - 1)
+	      lexer.split_current_token (
+		{Token::make_int (current_loc, std::move (prefix),
+				  CORETYPE_PURE_DECIMAL),
+		 Token::make (DOT, current_loc + 1)});
+	    else
+	      lexer.split_current_token (
+		{Token::make_int (current_loc, std::move (prefix),
+				  CORETYPE_PURE_DECIMAL),
+		 Token::make (DOT, current_loc + 1),
+		 Token::make_int (current_loc + 2, std::move (suffix),
+				  CORETYPE_PURE_DECIMAL)});
 	    return parse_tuple_index_expr (tok, std::move (left),
 					   std::move (outer_attrs),
 					   restrictions);