[Test] Confirm warnings are still warnings in Swift 3.2, errors are errors in Swift 4.0.

Fixes rdar://problem/28961650 .

Author: huonw

test/Parse/swift3_warnings_swift4_errors_version_3.swift

@@ -0,0 +1,26 @@
+// RUN: %target-swift-frontend -typecheck -verify -swift-version 3 %s
+
+protocol Operator {
+  func +(lhs: Self, rhs: Self) -> Self // expected-warning {{operator '+' declared in protocol must be 'static'}}
+}
+
+func foo(x: Int..., _: String) {} // expected-warning {{a parameter following a variadic parameter requires a label}}
+
+protocol P1 {}
+protocol P2 {}
+
+let x: protocol<> // expected-warning {{'protocol<>' syntax is deprecated; use 'Any' instead}}
+let y: protocol<P1> // expected-warning {{'protocol<...>' composition syntax is deprecated and not needed here}}}
+let z: protocol<P1, P2> // expected-warning {{'protocol<...>' composition syntax is deprecated; join the protocols using '&'}}
+
+func bar(f: @noescape () -> ()) {} // expected-warning {{@noescape is the default and is deprecated}}
+
+func baz(f: @autoclosure(escaping) () -> ()) {} // expected-warning {{@autoclosure(escaping) is deprecated; use @autoclosure @escaping instead}}
+
+prefix operator +++ {} // expected-warning {{operator should no longer be declared with body}}
+postfix operator +++ {} // expected-warning {{operator should no longer be declared with body}}
+infix operator +++ {} // expected-warning {{operator should no longer be declared with body}}
+infix operator +++* { // expected-warning {{operator should no longer be declared with body; use a precedence group instead}}
+  associativity right
+}
+

test/Parse/swift3_warnings_swift4_errors_version_4.swift

@@ -0,0 +1,25 @@
+// RUN: %target-swift-frontend -typecheck -verify -swift-version 4 %s
+
+protocol Operator {
+  func +(lhs: Self, rhs: Self) -> Self // expected-error {{operator '+' declared in protocol must be 'static'}}
+}
+
+func foo(x: Int..., _: String) {} // expected-error {{a parameter following a variadic parameter requires a label}}
+
+protocol P1 {}
+protocol P2 {}
+
+let x: protocol<> // expected-error {{'protocol<>' syntax has been removed; use 'Any' instead}}
+let y: protocol<P1> // expected-error {{'protocol<...>' composition syntax has been removed and is not needed here}}}
+let z: protocol<P1, P2> // expected-error {{'protocol<...>' composition syntax has been removed; join the protocols using '&'}}
+
+func bar(f: @noescape () -> ()) {} // expected-error {{@noescape is the default and has been removed}}
+
+func baz(f: @autoclosure(escaping) () -> ()) {} // expected-error {{@autoclosure(escaping) has been removed; use @autoclosure @escaping instead}}
+
+prefix operator +++ {} // expected-error {{operator should no longer be declared with body}}
+postfix operator +++ {} // expected-error {{operator should no longer be declared with body}}
+infix operator +++ {} // expected-error {{operator should no longer be declared with body}}
+infix operator +++* { // expected-error {{operator should no longer be declared with body; use a precedence group instead}}
+  associativity right
+}