vm_core.h: stringify in VM_ASSERT

* vm_core.h (VM_ASSERT): stringify expr here before expansion in
  RUBY_ASSERT_WHEN.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@56378 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Sun Oct  9 11:37:19 2016  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* vm_core.h (VM_ASSERT): stringify expr here before expansion in
+	  RUBY_ASSERT_WHEN.
+
 Sat Oct  8 10:54:22 2016  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* ext/-test-/memory_status/memory_status.c (read_status): use

vm_core.h

@@ -46,7 +46,7 @@
 
 #if VM_CHECK_MODE > 0
 #define VM_ASSERT(expr) ( \
-	RUBY_ASSERT_WHEN(VM_CHECK_MODE > 0, expr))
+	RUBY_ASSERT_MESG_WHEN(VM_CHECK_MODE > 0, expr, #expr))
 
 #define VM_UNREACHABLE(func) rb_bug(#func ": unreachable")