diff --git a/bin/sh/alias.c b/bin/sh/alias.c
index e67ad649ff7..bbcf5fbe17e 100644
--- a/bin/sh/alias.c
+++ b/bin/sh/alias.c
@@ -63,17 +63,8 @@ setalias(const char *name, const char *val)
 {
 	struct alias *ap, **app;
 
+	unalias(name);
 	app = hashalias(name);
-	for (ap = *app; ap; ap = ap->next) {
-		if (equal(name, ap->name)) {
-			INTOFF;
-			ckfree(ap->val);
-			ap->val	= savestr(val);
-			INTON;
-			return;
-		}
-	}
-	/* not found */
 	INTOFF;
 	ap = ckmalloc(sizeof (struct alias));
 	ap->name = savestr(name);
diff --git a/bin/sh/tests/parser/Makefile b/bin/sh/tests/parser/Makefile
index dd749e34b52..28816a92680 100644
--- a/bin/sh/tests/parser/Makefile
+++ b/bin/sh/tests/parser/Makefile
@@ -24,6 +24,7 @@ ${PACKAGE}FILES+=	alias14.0
 ${PACKAGE}FILES+=	alias15.0 alias15.0.stdout
 ${PACKAGE}FILES+=	alias16.0
 ${PACKAGE}FILES+=	alias17.0
+${PACKAGE}FILES+=	alias18.0
 ${PACKAGE}FILES+=	and-pipe-not.0
 ${PACKAGE}FILES+=	case1.0
 ${PACKAGE}FILES+=	case2.0
diff --git a/bin/sh/tests/parser/alias18.0 b/bin/sh/tests/parser/alias18.0
new file mode 100644
index 00000000000..74234fe72c0
--- /dev/null
+++ b/bin/sh/tests/parser/alias18.0
@@ -0,0 +1,8 @@
+# $FreeBSD$
+
+v=1
+alias a='alias a=v=2
+v=3
+a'
+eval a
+[ "$v" = 2 ]