fix #47410, syntax error with anonfn inside elseif and short-circuit op (#47499)

Author: JeffBezanson

src/julia-syntax.scm

@@ -4404,6 +4404,9 @@ f(x) = yt(x)
             cnd)))
     (define (emit-cond cnd break-labels endl)
       (let* ((cnd (if (and (pair? cnd) (eq? (car cnd) 'block))
+                      (flatten-ex 'block cnd)
+                      cnd))
+             (cnd (if (and (pair? cnd) (eq? (car cnd) 'block))
                        (begin (if (length> cnd 2) (compile (butlast cnd) break-labels #f #f))
                               (last cnd))
                        cnd))

test/syntax.jl

@@ -3422,3 +3422,10 @@ end
 # issue #46251
 @test begin; global value = 1; (value, value += 1) end == (1, 2)
 @test begin; global value = 1; "($(value), $(value += 1))" end == "(1, 2)"
+
+# issue #47410
+# note `eval` is needed since this needs to be at the top level
+@test eval(:(if false
+             elseif false || (()->true)()
+                 42
+             end)) == 42