diff --git a/contrib/40.srfi/src/106.c b/contrib/40.srfi/src/106.c
index 72633481..5f1e4c3a 100644
--- a/contrib/40.srfi/src/106.c
+++ b/contrib/40.srfi/src/106.c
@@ -219,11 +219,7 @@ pic_socket_socket_recv(pic_state *pic)
 
   ensure_socket_is_open(pic, sock);
 
-  buf = pic_blob(pic, pic_blob_value(pic, NULL, size), NULL);
-  if (buf == NULL && size > 0) {
-    /* XXX: Is it really OK? */
-    pic_panic(pic, "memory exhausted");
-  }
+  buf = pic_alloca(pic, size);
 
   errno = 0;
   do {
diff --git a/extlib/benz/gc.c b/extlib/benz/gc.c
index 8dc5286b..375c4dab 100644
--- a/extlib/benz/gc.c
+++ b/extlib/benz/gc.c
@@ -403,16 +403,8 @@ gc_mark_object(pic_state *pic, struct pic_object *obj)
     }
     break;
   }
-  case PIC_TYPE_NIL:
-  case PIC_TYPE_TRUE:
-  case PIC_TYPE_FALSE:
-  case PIC_TYPE_FLOAT:
-  case PIC_TYPE_INT:
-  case PIC_TYPE_CHAR:
-  case PIC_TYPE_EOF:
-  case PIC_TYPE_UNDEF:
-  case PIC_TYPE_INVALID:
-    pic_panic(pic, "logic flaw");
+  default:
+    PIC_UNREACHABLE();
   }
 }
 
@@ -574,16 +566,8 @@ gc_finalize_object(pic_state *pic, struct pic_object *obj)
   case PIC_TYPE_CP:
     break;
 
-  case PIC_TYPE_NIL:
-  case PIC_TYPE_TRUE:
-  case PIC_TYPE_FALSE:
-  case PIC_TYPE_FLOAT:
-  case PIC_TYPE_INT:
-  case PIC_TYPE_CHAR:
-  case PIC_TYPE_EOF:
-  case PIC_TYPE_UNDEF:
-  case PIC_TYPE_INVALID:
-    pic_panic(pic, "logic flaw");
+  default:
+    PIC_UNREACHABLE();
   }
 }
 
diff --git a/extlib/benz/state.c b/extlib/benz/state.c
index aac2910e..b8d975d4 100644
--- a/extlib/benz/state.c
+++ b/extlib/benz/state.c
@@ -178,13 +178,7 @@ pic_init_core(pic_state *pic)
 
   pic_defun(pic, "features", pic_features);
 
-  pic_try {
-    pic_load_cstr(pic, &pic_boot[0][0]);
-  }
-  pic_catch {
-    pic_print_backtrace(pic, xstdout);
-    pic_panic(pic, "");
-  }
+  pic_load_cstr(pic, &pic_boot[0][0]);
 }
 
 pic_state *
diff --git a/extlib/benz/var.c b/extlib/benz/var.c
index 8f4b2ef7..72105734 100644
--- a/extlib/benz/var.c
+++ b/extlib/benz/var.c
@@ -17,7 +17,7 @@ var_get(pic_state *pic, pic_value var)
       return pic_weak_ref(pic, weak, var);
     }
   }
-  pic_panic(pic, "logic flaw");
+  PIC_UNREACHABLE();
 }
 
 static pic_value