fix #15186, regression in if lowering

src/julia-syntax.scm

@@ -2958,7 +2958,7 @@ f(x) = yt(x)
                (emit test)
                (let ((v1 (compile (caddr e) break-labels value tail)))
                  (if val (emit `(= ,val ,v1)))
-                 (if (and (not tail) (length> e 3) (not (equal? (cadddr e) '(null))))
+                 (if (and (not tail) (or (length> e 3) val))
                      (emit end-jump))
                  (set-car! (cddr test) (make&mark-label))
                  (let ((v2 (if (length> e 3)

test/core.jl

@@ -3758,3 +3758,10 @@ module I13229
     end
     @test z == 10
 end
+
+# issue #15186
+let ex = quote
+             $(if true; :(test); end)
+         end
+    @test ex.args[2] == :test
+end