From: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>
Date: Thu, 3 Aug 2023 13:28:40 +0000 (+0200)
Subject: gccrs: fix lexer exponent output on tuple indices
X-Git-Tag: basepoints/gcc-15~2211
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a7eacd8879e422485a0044be37d03a05d3ed262e;p=thirdparty%2Fgcc.git

gccrs: fix lexer exponent output on tuple indices

The lexer did output a literal for values such as 42.e wich are invalid
in rust.

gcc/rust/ChangeLog:

	* lex/rust-lex.cc (Lexer::parse_decimal_int_or_float): Only
	accept digits after a dot instead of accepting any float
	member.

Signed-off-by: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>
---

diff --git a/gcc/rust/lex/rust-lex.cc b/gcc/rust/lex/rust-lex.cc
index 53895c141992..8142aa0cf782 100644
--- a/gcc/rust/lex/rust-lex.cc
+++ b/gcc/rust/lex/rust-lex.cc
@@ -2295,7 +2295,17 @@ Lexer::parse_decimal_int_or_float (location_t loc)
   length += std::get<1> (initial_decimal);
 
   // detect float literal
-  if (current_char == '.' && is_float_digit (peek_input (1).value))
+  //
+  // Note:
+  //
+  // We should not use is_float_digit () for this verification but instead
+  // directly ISDIGIT because rust does not support non digit values right after
+  // a dot.
+  // The following value is not legal in rust:
+  // let a = 3.e1;
+  // A `0` should be put between the dot and the exponent to be valid
+  // (eg. 3.0e1).
+  if (current_char == '.' && ISDIGIT (peek_input (1).value))
     {
       // float with a '.', parse another decimal into it