Add tests

Author: Sima Nerush

test/Constraints/pack-expansion-expressions.swift

@@ -604,3 +604,20 @@ func test_that_expansions_are_bound_early() {
       })
   }
 }
+
+// https://github.com/apple/swift/issues/66393
+do {
+    struct S<each T> {
+        var property: (repeat each T) -> Void { // expected-note {{'property' declared here}}
+            get {}
+        }
+
+        func method(_: repeat each T) {} // expected-note {{'method' declared here}}
+    }
+    S<Int, Bool>().method((5, true))
+    // expected-error@-1 {{value pack expansion at parameter #0 expects 2 separate arguments; remove extra parentheses to change tuple into separate arguments}}
+
+    S<Int, Bool>().property((5, true))
+    // expected-error@-1 {{value pack expansion at parameter #0 expects 2 separate arguments; remove extra parentheses to change tuple into separate arguments}}
+    // expected-error@-2 {{cannot pass value pack expansion to non-pack parameter of type 'repeat each T'}}
+}