[Sema] Suppress deprecation warnings in synthesized code

Author: AnthonyLatsis

lib/Sema/TypeCheckAvailability.cpp

@@ -1937,6 +1937,12 @@ void TypeChecker::diagnoseIfDeprecated(SourceRange ReferenceRange,
   if (!Attr)
     return;
 
+  // We don't want deprecated declarations to trigger warnings
+  // in synthesized code.
+  if (ReferenceRange.isInvalid() &&
+      isInsideImplicitFunction(ReferenceRange, ReferenceDC)) {
+    return;
+  }
   // We match the behavior of clang to not report deprecation warnings
   // inside declarations that are themselves deprecated on all deployment
   // targets.

test/attr/attr_availability.swift

@@ -1028,3 +1028,16 @@ struct UnavailableAccessors {
     other[alsoUnavailable: 0] += 1 // expected-error {{'subscript(alsoUnavailable:)' is unavailable: bad subscript!}} {{none}}
   }
 }
+
+// Should produce no warnings.
+enum SR8634_Enum: Int {
+  case a
+  @available(*, deprecated, message: "I must not be raised in synthesized code")
+  case b
+  case c
+}
+
+struct SR8634_Struct: Equatable {
+  @available(*, deprecated, message: "I must not be raised in synthesized code", renamed: "x")
+  let a: Int
+}