From 65d1aa7a779b30bf5b0e7b968b3980b702b08b2c Mon Sep 17 00:00:00 2001
From: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Tue, 9 Apr 2019 18:40:39 -0300
Subject: [PATCH] Syntax should not allow numbers touching identifiers

Code like 'a = 1print()' should not be accepted.
---
 llex.c              | 2 ++
 testes/literals.lua | 9 +++++++++
 2 files changed, 11 insertions(+)

diff --git a/llex.c b/llex.c
index b0bab377..bb81cec4 100644
--- a/llex.c
+++ b/llex.c
@@ -228,6 +228,8 @@ static int read_numeral (LexState *ls, SemInfo *seminfo) {
       save_and_next(ls);
     else break;
   }
+  if (lislalnum(ls->current))  /* is numeral touching an alpha num? */
+    save_and_next(ls);  /* force an error */
   save(ls, '\0');
   if (luaO_str2num(luaZ_buffer(ls->buff), &obj) == 0)  /* format error? */
     lexerror(ls, "malformed number", TK_FLT);
diff --git a/testes/literals.lua b/testes/literals.lua
index fc45d4ad..27f9377d 100644
--- a/testes/literals.lua
+++ b/testes/literals.lua
@@ -306,4 +306,13 @@ assert(not load"a = 'non-ending string\n'")
 assert(not load"a = '\\345'")
 assert(not load"a = [=x]")
 
+local function malformednum (n, exp)
+  local s, msg = load("return " .. n)
+  assert(not s and string.find(msg, exp))
+end
+
+malformednum("0xe-", "near <eof>")
+malformednum("0xep-p", "malformed number")
+malformednum("1print()", "malformed number")
+
 print('OK')