--- a/src/eval.c
+++ b/src/eval.c
@@ -6573,15 +6573,15 @@ list2string(tv, copyID)
 
 /*
  * Join list "l" into a string in "*gap", using separator "sep".
- * When "echo" is TRUE use String as echoed, otherwise as inside a List.
+ * When "echo_style" is TRUE use String as echoed, otherwise as inside a List.
  * Return FAIL or OK.
  */
     static int
-list_join(gap, l, sep, echo, copyID)
+list_join(gap, l, sep, echo_style, copyID)
     garray_T	*gap;
     list_T	*l;
     char_u	*sep;
-    int		echo;
+    int		echo_style;
     int		copyID;
 {
     int		first = TRUE;
@@ -6597,7 +6597,7 @@ list_join(gap, l, sep, echo, copyID)
 	else
 	    ga_concat(gap, sep);
 
-	if (echo)
+	if (echo_style)
 	    s = echo_string(&item->li_tv, &tofree, numbuf, copyID);
 	else
 	    s = tv2string(&item->li_tv, &tofree, numbuf, copyID);
@@ -17893,7 +17893,7 @@ f_tr(argvars, rettv)
     typval_T	*argvars;
     typval_T	*rettv;
 {
-    char_u	*instr;
+    char_u	*in_str;
     char_u	*fromstr;
     char_u	*tostr;
     char_u	*p;
@@ -17910,7 +17910,7 @@ f_tr(argvars, rettv)
     char_u	buf2[NUMBUFLEN];
     garray_T	ga;
 
-    instr = get_tv_string(&argvars[0]);
+    in_str = get_tv_string(&argvars[0]);
     fromstr = get_tv_string_buf_chk(&argvars[1], buf);
     tostr = get_tv_string_buf_chk(&argvars[2], buf2);
 
@@ -17936,19 +17936,19 @@ error:
 	}
 
     /* fromstr and tostr have to contain the same number of chars */
-    while (*instr != NUL)
+    while (*in_str != NUL)
     {
 #ifdef FEAT_MBYTE
 	if (has_mbyte)
 	{
-	    inlen = (*mb_ptr2len)(instr);
-	    cpstr = instr;
+	    inlen = (*mb_ptr2len)(in_str);
+	    cpstr = in_str;
 	    cplen = inlen;
 	    idx = 0;
 	    for (p = fromstr; *p != NUL; p += fromlen)
 	    {
 		fromlen = (*mb_ptr2len)(p);
-		if (fromlen == inlen && STRNCMP(instr, p, inlen) == 0)
+		if (fromlen == inlen && STRNCMP(in_str, p, inlen) == 0)
 		{
 		    for (p = tostr; *p != NUL; p += tolen)
 		    {
@@ -17967,11 +17967,11 @@ error:
 		++idx;
 	    }
 
-	    if (first && cpstr == instr)
+	    if (first && cpstr == in_str)
 	    {
 		/* Check that fromstr and tostr have the same number of
 		 * (multi-byte) characters.  Done only once when a character
-		 * of instr doesn't appear in fromstr. */
+		 * of in_str doesn't appear in fromstr. */
 		first = FALSE;
 		for (p = tostr; *p != NUL; p += tolen)
 		{
@@ -17986,18 +17986,18 @@ error:
 	    mch_memmove((char *)ga.ga_data + ga.ga_len, cpstr, (size_t)cplen);
 	    ga.ga_len += cplen;
 
-	    instr += inlen;
+	    in_str += inlen;
 	}
 	else
 #endif
 	{
 	    /* When not using multi-byte chars we can do it faster. */
-	    p = vim_strchr(fromstr, *instr);
+	    p = vim_strchr(fromstr, *in_str);
 	    if (p != NULL)
 		ga_append(&ga, tostr[p - fromstr]);
 	    else
-		ga_append(&ga, *instr);
-	    ++instr;
+		ga_append(&ga, *in_str);
+	    ++in_str;
 	}
     }