[Test] Add AnyKeyPath test and move keypath diagnostics

Author: Amritpan Kaur

test/Constraints/diagnostics.swift

@@ -1565,18 +1565,18 @@ func testNilCoalescingOperatorRemoveFix() {
   let _ = "" /* This is a comment */ ?? "" // expected-warning {{left side of nil coalescing operator '??' has non-optional type 'String', so the right side is never used}} {{13-43=}}
 
   let _ = "" // This is a comment
-    ?? "" // expected-warning {{left side of nil coalescing operator '??' has non-optional type 'String', so the right side is never used}} {{1567:13-1568:10=}}
+    ?? "" // expected-warning {{left side of nil coalescing operator '??' has non-optional type 'String', so the right side is never used}} {{1555:13-1556:10=}}
 
   let _ = "" // This is a comment
     /*
      * The blank line below is part of the test case, do not delete it
      */
 
-    ?? "" // expected-warning {{left side of nil coalescing operator '??' has non-optional type 'String', so the right side is never used}} {{1570:13-1575:10=}}
+    ?? "" // expected-warning {{left side of nil coalescing operator '??' has non-optional type 'String', so the right side is never used}} {{1558:13-1563:10=}}
 
-  if ("" ?? // This is a comment // expected-warning {{left side of nil coalescing operator '??' has non-optional type 'String', so the right side is never used}} {{1577:9-1578:9=}}
+  if ("" ?? // This is a comment // expected-warning {{left side of nil coalescing operator '??' has non-optional type 'String', so the right side is never used}} {{9-1566:9=}}
       "").isEmpty {}
 
   if ("" // This is a comment
-      ?? "").isEmpty {} // expected-warning {{left side of nil coalescing operator '??' has non-optional type 'String', so the right side is never used}} {{1580:9-1581:12=}}
+      ?? "").isEmpty {} // expected-warning {{left side of nil coalescing operator '??' has non-optional type 'String', so the right side is never used}} {{1568:9-1569:12=}}
 }

test/Constraints/keypath.swift

@@ -236,3 +236,14 @@ func issue_65965() {
   writeKP = \.v
   // expected-error@-1 {{key path value type 'KeyPath<S, String>' cannot be converted to contextual type 'WritableKeyPath<S, String>'}}
 }
+
+func test_any_key_path() {
+  struct S {
+    var v: String
+  }
+  
+  var anyKP: AnyKeyPath
+  anyKP = \S.v
+  anyKP = \.v
+  // expected-error@-1 {{cannot infer key path type from context; consider explicitly specifying a root type}}
+}