diff --git a/src/hb-ot-layout-gpos-private.hh b/src/hb-ot-layout-gpos-private.hh
index cfd2411d0..200f353e6 100644
--- a/src/hb-ot-layout-gpos-private.hh
+++ b/src/hb-ot-layout-gpos-private.hh
@@ -1487,11 +1487,10 @@ struct PosLookup : Lookup
   inline bool apply_once (hb_ot_layout_context_t *layout,
 			  hb_buffer_t    *buffer,
 			  unsigned int    context_length,
-			  unsigned int    nesting_level_left,
-			  unsigned int    apply_depth) const
+			  unsigned int    nesting_level_left) const
   {
     unsigned int lookup_type = get_type ();
-    hb_apply_context_t context[1];
+    hb_apply_context_t context[1] = {{}};
 
     context->layout = layout;
     context->buffer = buffer;
@@ -1528,7 +1527,7 @@ struct PosLookup : Lookup
       bool done;
       if (~IN_MASK (buffer->in_pos) & mask)
       {
-	  done = apply_once (layout, buffer, NO_CONTEXT, MAX_NESTING_LEVEL, 0);
+	  done = apply_once (layout, buffer, NO_CONTEXT, MAX_NESTING_LEVEL);
 	  ret |= done;
       }
       else
@@ -1612,7 +1611,7 @@ static inline bool position_lookup (APPLY_ARG_DEF, unsigned int lookup_index)
   if (unlikely (context->context_length < 1))
     return false;
 
-  return l.apply_once (context->layout, context->buffer, context->context_length, context->nesting_level_left - 1, apply_depth + 1);
+  return l.apply_once (context->layout, context->buffer, context->context_length, context->nesting_level_left - 1);
 }
 
 
diff --git a/src/hb-ot-layout-gsub-private.hh b/src/hb-ot-layout-gsub-private.hh
index 87dfcd2e8..19297c483 100644
--- a/src/hb-ot-layout-gsub-private.hh
+++ b/src/hb-ot-layout-gsub-private.hh
@@ -772,11 +772,10 @@ struct SubstLookup : Lookup
   inline bool apply_once (hb_ot_layout_context_t *layout,
 			  hb_buffer_t *buffer,
 			  unsigned int context_length,
-			  unsigned int nesting_level_left,
-			  unsigned int apply_depth) const
+			  unsigned int nesting_level_left) const
   {
     unsigned int lookup_type = get_type ();
-    hb_apply_context_t context[1];
+    hb_apply_context_t context[1] = {{}};
 
     context->layout = layout;
     context->buffer = buffer;
@@ -828,7 +827,7 @@ struct SubstLookup : Lookup
 	while (buffer->in_pos < buffer->in_length)
 	{
 	  if ((~IN_MASK (buffer->in_pos) & mask) &&
-	      apply_once (layout, buffer, NO_CONTEXT, MAX_NESTING_LEVEL, 0))
+	      apply_once (layout, buffer, NO_CONTEXT, MAX_NESTING_LEVEL))
 	    ret = true;
 	  else
 	    _hb_buffer_next_glyph (buffer);
@@ -844,7 +843,7 @@ struct SubstLookup : Lookup
 	do
 	{
 	  if ((~IN_MASK (buffer->in_pos) & mask) &&
-	      apply_once (layout, buffer, NO_CONTEXT, MAX_NESTING_LEVEL, 0))
+	      apply_once (layout, buffer, NO_CONTEXT, MAX_NESTING_LEVEL))
 	    ret = true;
 	  else
 	    buffer->in_pos--;
@@ -931,7 +930,7 @@ static inline bool substitute_lookup (APPLY_ARG_DEF, unsigned int lookup_index)
   if (unlikely (context->context_length < 1))
     return false;
 
-  return l.apply_once (context->layout, context->buffer, context->context_length, context->nesting_level_left - 1, apply_depth + 1);
+  return l.apply_once (context->layout, context->buffer, context->context_length, context->nesting_level_left - 1);
 }
 
 
diff --git a/src/hb-ot-layout-gsubgpos-private.hh b/src/hb-ot-layout-gsubgpos-private.hh
index 80968dce6..ad4e404c1 100644
--- a/src/hb-ot-layout-gsubgpos-private.hh
+++ b/src/hb-ot-layout-gsubgpos-private.hh
@@ -36,18 +36,14 @@
 #endif
 
 #define TRACE_APPLY() \
-	HB_STMT_START { \
-	  if (HB_DEBUG_APPLY) \
-		  _hb_trace ("APPLY", HB_FUNC, this, apply_depth, HB_DEBUG_APPLY); \
-	} HB_STMT_END
+	hb_trace_t<HB_DEBUG_APPLY> trace (&context->debug_depth); \
+	trace.log ("APPLY", HB_FUNC, this);
 
 
 #define APPLY_ARG_DEF \
-	hb_apply_context_t *context, \
-	unsigned int apply_depth HB_UNUSED
+	hb_apply_context_t *context
 #define APPLY_ARG \
-	context, \
-	(HB_DEBUG_APPLY ? apply_depth + 1 : 0)
+	context
 
 struct hb_apply_context_t
 {
@@ -57,6 +53,7 @@ struct hb_apply_context_t
   unsigned int nesting_level_left;
   unsigned int lookup_flag;
   unsigned int property; /* propety of first glyph (TODO remove) */
+  unsigned int debug_depth;
 };