fix Issue 21432 - [CTFE] Cannot declare enum array in function scope

compiler/test/compilable/test21432.d

@@ -0,0 +1,25 @@
+// https://issues.dlang.org/show_bug.cgi?id=21432
+auto issue21432()
+{
+    enum int[] a = [];
+    return a;
+}
+
+enum test21432a = issue21432;
+
+///////////////////////
+
+double issue21432b(double r)
+{
+    enum double[4] poly = [
+        0x1.ffffffffffdbdp-2,
+        0x1.555555555543cp-3,
+        0x1.55555cf172b91p-5,
+        0x1.1111167a4d017p-7,
+    ];
+
+    immutable r2 = r * r;
+    return r + r2 * (poly[0] + r * poly[1]) + r2 * r2 * (poly[2] + r * poly[3]);
+}
+
+enum test21432b = issue21432b(-0x1p-1);