Don't handle unclassified switch cases for now

Previously we would silently add these to the
success block. For now, let's leave them
unhandled.

Author: hamishknight

include/swift/AST/DiagnosticsRefactoring.def

@@ -70,5 +70,7 @@ ERROR(callback_multiple_case_items, none, "cannot refactor switch using a case w
 
 ERROR(callback_where_case_item, none, "cannot refactor switch using a case with where clause", ())
 
+ERROR(unknown_callback_case_item, none, "cannot refactor complex case conditions", ())
+
 #define UNDEFINE_DIAGNOSTIC_MACROS
 #include "DefineDiagnosticMacros.h"

lib/IDE/Refactoring.cpp

@@ -5326,7 +5326,12 @@ struct CallbackClassifier {
       auto CC = classifyCallbackCondition(
           CallbackCondition(ErrParam, &Items[0]), SuccessNodes,
           /*elseStmt*/ nullptr);
-      if (CC && CC->Path == ConditionPath::FAILURE)
+      if (!CC) {
+        DiagEngine.diagnose(CS->getLoc(), diag::unknown_callback_case_item);
+        return;
+      }
+
+      if (CC->Path == ConditionPath::FAILURE)
         std::swap(Block, OtherBlock);
 
       // We'll be dropping the case, but make sure to keep any attached
@@ -5339,8 +5344,7 @@ struct CallbackClassifier {
         Block->addPossibleCommentLoc(SS->getRBraceLoc());
 
       setNodes(Block, OtherBlock, std::move(SuccessNodes));
-      if (CC)
-        Block->addBinding(*CC, DiagEngine);
+      Block->addBinding(*CC, DiagEngine);
       if (DiagEngine.hadAnyError())
         return;
     }

test/refactoring/ConvertAsync/convert_pattern.swift

@@ -3,6 +3,7 @@
 enum E : Error { case e }
 
 func anyCompletion(_ completion: (Any?, Error?) -> Void) {}
+func anyResultCompletion(_ completion: (Result<Any?, Error>) -> Void) {}
 
 // RUN: %refactor -convert-call-to-async-alternative -dump-text -source-filename %s -pos=%(line+1):1 | %FileCheck -check-prefix=TEST-UNHANDLED %s
 anyCompletion { val, err in
@@ -43,3 +44,77 @@ anyCompletion { val, err in
 // TEST-UNHANDLED-NEXT: if case let "" as String = <#x#> {
 // TEST-UNHANDLED-NEXT:   print("g")
 // TEST-UNHANDLED-NEXT: }
+
+// RUN: not %refactor -convert-call-to-async-alternative -dump-text -source-filename %s -pos=%(line+1):1
+anyResultCompletion { res in
+  switch res {
+  case .success(let unwrapped?):
+    print(unwrapped)
+  case .success(let x):
+    print(x)
+  case .failure:
+    print("oh no")
+  }
+}
+
+// RUN: not %refactor -convert-call-to-async-alternative -dump-text -source-filename %s -pos=%(line+1):1
+anyResultCompletion { res in
+  switch res {
+  case .success(let str as String):
+    print(str)
+  case .success(let x):
+    print(x)
+  case .failure:
+    print("oh no")
+  }
+}
+
+// RUN: not %refactor -convert-call-to-async-alternative -dump-text -source-filename %s -pos=%(line+1):1
+anyResultCompletion { res in
+  switch res {
+  case .success(E.e?):
+    print("ee")
+  case .success(let x):
+    print(x)
+  case .failure:
+    print("oh no")
+  }
+}
+
+// RUN: not %refactor -convert-call-to-async-alternative -dump-text -source-filename %s -pos=%(line+1):1
+anyResultCompletion { res in
+  switch res {
+  case .success("" as String):
+    print("empty string")
+  case .success(let x):
+    print(x)
+  case .failure:
+    print("oh no")
+  }
+}
+
+// FIXME: This should ideally be turned into a 'catch let e as E'.
+// RUN: not %refactor -convert-call-to-async-alternative -dump-text -source-filename %s -pos=%(line+1):1
+anyResultCompletion { res in
+  switch res {
+  case .success(let a):
+    print(a)
+  case .failure(let e as E):
+    print("oh no e")
+  case .failure:
+    print("oh no")
+  }
+}
+
+// FIXME: This should ideally be turned into a 'catch E.e'.
+// RUN: not %refactor -convert-call-to-async-alternative -dump-text -source-filename %s -pos=%(line+1):1
+anyResultCompletion { res in
+  switch res {
+  case .success(let a):
+    print(a)
+  case .failure(E.e):
+    print("oh no ee")
+  case .failure:
+    print("oh no")
+  }
+}