diff --git a/include/mimalloc.h b/include/mimalloc.h
index 1f12a41e..7ffb55d9 100644
--- a/include/mimalloc.h
+++ b/include/mimalloc.h
@@ -282,13 +282,13 @@ typedef struct mi_heap_area_s {
   size_t block_size;  // size in bytes of each block
 } mi_heap_area_t;
 
-// Information about a block
+// Information about an allocated block. 
 typedef struct mi_block_info_s {
   void*       block;          // start of the block
   size_t      size;           // full size including padding etc.
   size_t      usable_size;    // usable size (available for in-place realloc)
-  size_t      allocated_size; // actual allocated size (only precise in debug mode with padding)
-  bool        valid;          // is the block valid? (only detects corrupt blocks with padding enabled)
+  size_t      allocated_size; // actual allocated size (only precise in debug mode with padding enabled)
+  bool        valid;          // is the block valid? (only detects heap overflow with padding enabled)
   mi_source_t source;         // the source location that allocated this block (only valid in debug mode with padding)
 } mi_block_info_t;
 
diff --git a/src/heap.c b/src/heap.c
index 338f0c0c..17498ba2 100644
--- a/src/heap.c
+++ b/src/heap.c
@@ -608,13 +608,13 @@ void mi_heap_print_json(mi_heap_t* heap, mi_output_fun* out, void* arg) {
 
 bool mi_heap_is_empty(mi_heap_t* heap) {
   if (heap==NULL) heap = mi_heap_get_default();
-  mi_collect(false);
+  mi_heap_collect(heap,false);
   return (heap->page_count == 0);
 }
 
 void mi_heap_check_leak(mi_heap_t* heap, mi_output_fun* out, void* arg) {
   if (!mi_heap_is_empty(heap)) {
-    _mi_fprintf(out,arg,"mimalloc: potential memory leak detected. Current heap blocks:\n");
+    _mi_fprintf(out,arg,"mimalloc: potential memory leak detected; current heap blocks:\n");
     mi_heap_print_json(heap, out, arg);
   }
 }