Merge closures_swift4.swift back into closures.swift.

test/Constraints/closures.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -swift-version 4
+// RUN: %target-typecheck-verify-swift
 
 func myMap<T1, T2>(_ array: [T1], _ fn: (T1) -> T2) -> [T2] {}
 
@@ -539,6 +539,15 @@ _ = ["hi"].compactMap { $0.isEmpty ? nil : $0 }
 // rdar://problem/32432145 - compiler should emit fixit to remove "_ in" in closures if 0 parameters is expected
 
 func r32432145(_ a: () -> ()) {}
+
+r32432145 { _ in let _ = 42 }
+// expected-error@-1 {{contextual closure type '() -> ()' expects 0 arguments, but 1 was used in closure body}} {{13-17=}}
+
+r32432145 { _ in
+  // expected-error@-1 {{contextual closure type '() -> ()' expects 0 arguments, but 1 was used in closure body}} {{13-17=}}
+  print("answer is 42")
+}
+
 r32432145 { _,_ in
   // expected-error@-1 {{contextual closure type '() -> ()' expects 0 arguments, but 2 were used in closure body}} {{13-19=}}
   print("answer is 42")
@@ -733,3 +742,10 @@ func takesTwoInOut(_: (Int, inout Int) -> ()) {}
 
 takesTwo { _ in } // expected-error {{contextual closure type '(Int, Int) -> ()' expects 2 arguments, but 1 was used in closure body}}
 takesTwoInOut { _ in } // expected-error {{contextual closure type '(Int, inout Int) -> ()' expects 2 arguments, but 1 was used in closure body}}
+
+// <rdar://problem/20371273> Type errors inside anonymous functions don't provide enough information
+func f20371273() {
+  let x: [Int] = [1, 2, 3, 4]
+  let y: UInt = 4
+  _ = x.filter { ($0 + y)  > 42 } // expected-error {{'+' is unavailable}}
+}