Fix Issue 23271 - Mark lowered DeclExps in array appends as exptemp (#14328)

compiler/test/compilable/testgotoskips.d

@@ -0,0 +1,17 @@
+/*
+    Tests to defend against false positives from the goto skips over decl errors
+*/
+// https://issues.dlang.org/show_bug.cgi?id=23271
+class A {
+        private static A[] active;
+        private void test() {
+                foreach(a; active) {
+                    if(a is this)
+                         goto label;
+                }
+                // used to say Error: `goto` skips declaration of variable `s.A.test.__appendtmp4` at s.d(...)
+                active ~= this;
+            label:
+                return;
+        }
+}