diff --git a/shell/ash.c b/shell/ash.c
index ee7642a..33a477d 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -11316,9 +11316,9 @@
 				parenlevel--;
 			} else {
 				if (pgetc() == ')') {
+					c = CTLENDARI;
 					if (--arinest == 0) {
 						syntax = prevsyntax;
-						c = CTLENDARI;
 					}
 				} else {
 					/*
@@ -11809,18 +11809,12 @@
 	if (++arinest == 1) {
 		prevsyntax = syntax;
 		syntax = ARISYNTAX;
-		USTPUTC(CTLARI, out);
-		if (dblquote)
-			USTPUTC('"', out);
-		else
-			USTPUTC(' ', out);
-	} else {
-		/*
-		 * we collapse embedded arithmetic expansion to
-		 * parenthesis, which should be equivalent
-		 */
-		USTPUTC('(', out);
 	}
+	USTPUTC(CTLARI, out);
+	if (dblquote)
+		USTPUTC('"', out);
+	else
+		USTPUTC(' ', out);
 	goto parsearith_return;
 }
 #endif
diff --git a/shell/ash_test/ash-vars/var-do-not-collapse-arithmetic-expansion-at-parse-time.right b/shell/ash_test/ash-vars/var-do-not-collapse-arithmetic-expansion-at-parse-time.right
new file mode 100644
index 0000000..81a1585
--- /dev/null
+++ b/shell/ash_test/ash-vars/var-do-not-collapse-arithmetic-expansion-at-parse-time.right
@@ -0,0 +1,2 @@
+12
+9
diff --git a/shell/ash_test/ash-vars/var-do-not-collapse-arithmetic-expansion-at-parse-time.tests b/shell/ash_test/ash-vars/var-do-not-collapse-arithmetic-expansion-at-parse-time.tests
new file mode 100755
index 0000000..e97a08a
--- /dev/null
+++ b/shell/ash_test/ash-vars/var-do-not-collapse-arithmetic-expansion-at-parse-time.tests
@@ -0,0 +1,3 @@
+unset a
+echo $((3 + ${a:=$((4 + 5))}))
+echo $a