commit https://github.com/vim/vim/commit/5df1ed2de3fa9dcace996b9a0a4c9b3cea79cf1e Author: Bram Moolenaar <Bram@vim.org> Date: Tue Sep 1 16:25:34 2015 +0200 patch 7.4.845 Problem: Compiler warning for possible loss of data. Solution: Add a type cast. (Erich Ritz)

--- a/src/misc1.c
+++ b/src/misc1.c
@@ -3985,7 +3985,7 @@ expand_env_esc(srcp, dst, dstlen, esc, o
 		len = dstlen;
 	    vim_strncpy(dst, var, len);
 	    dst += len;
-	    dstlen -= len;
+	    dstlen -= (int)len;
 	    continue;
 	}
 #endif