diff --git a/src/read.c b/src/read.c
index 337c898e83..9718a3791a 100644
--- a/src/read.c
+++ b/src/read.c
@@ -501,17 +501,18 @@ void ReadCallVarAss (
     if (WarnOnUnboundGlobalsRNam == 0)
       WarnOnUnboundGlobalsRNam = RNamName("WarnOnUnboundGlobals");
 
-    if ( type == 'g'
-      && mode != 'i'
-      && STATE(CountNams) != 0
-      && var != STATE(CurrLHSGVar)
-      && VAL_GVAR(var) == 0
-      && ExprGVar(var) == 0
-      && ! STATE(IntrIgnoring)
-      && ! GlobalComesFromEnclosingForLoop(var)
-      && (GAPInfo == 0 || !IS_REC(GAPInfo) || !ISB_REC(GAPInfo,WarnOnUnboundGlobalsRNam) ||
-             ELM_REC(GAPInfo,WarnOnUnboundGlobalsRNam) != False )
-      && ! SyCompilePlease )
+    if ( type == 'g'                /* Reading a global variable          */
+      && mode != 'i'                /* Not inside 'IsBound'               */
+      && STATE(CountNams) != 0      /* Inside a function                  */
+      && var != STATE(CurrLHSGVar)  /* Not LHS of assignment              */
+      && VAL_GVAR(var) == 0         /* Not an existing global var         */
+      && ExprGVar(var) == 0         /* Or an auto var                     */
+      && ! STATE(IntrIgnoring)      /* Not currently ignoring parsed code */
+      && ! GlobalComesFromEnclosingForLoop(var) /* ? */
+      && (GAPInfo == 0 || !IS_REC(GAPInfo)
+          || !ISB_REC(GAPInfo,WarnOnUnboundGlobalsRNam) /* Warning enabled*/
+          ||  ELM_REC(GAPInfo,WarnOnUnboundGlobalsRNam) != False )
+      && ! SyCompilePlease )        /* Not compiling                      */
     {
         SyntaxWarning("Unbound global variable");
     }