diff --git a/include/swift/AST/DiagnosticEngine.h b/include/swift/AST/DiagnosticEngine.h
index ad73eac78834b..08a2c93c152bf 100644
--- a/include/swift/AST/DiagnosticEngine.h
+++ b/include/swift/AST/DiagnosticEngine.h
@@ -279,6 +279,19 @@ namespace swift {
     }
   };
 
+  namespace detail {
+  /// Stores information for an active diagnostic that hasn't been emitted yet.
+  /// This includes both "in-flight" diagnostics as well as diagnostics queued
+  /// for a transaction.
+  struct ActiveDiagnostic {
+    Diagnostic Diag;
+    SmallVector<DiagnosticInfo, 2> WrappedDiagnostics;
+    SmallVector<std::vector<DiagnosticArgument>, 4> WrappedDiagnosticArgs;
+
+    ActiveDiagnostic(Diagnostic diag) : Diag(std::move(diag)) {}
+  };
+  } // namespace detail
+
   /// A diagnostic that has no input arguments, so it is trivially-destructable.
   using ZeroArgDiagnostic = Diag<>;
   
@@ -293,33 +306,40 @@ namespace swift {
     friend class DiagnosticEngine;
     
     DiagnosticEngine *Engine;
+    unsigned Idx;
     bool IsActive;
     
     /// Create a new in-flight diagnostic. 
     ///
     /// This constructor is only available to the DiagnosticEngine.
-    InFlightDiagnostic(DiagnosticEngine &Engine)
-      : Engine(&Engine), IsActive(true) { }
-    
+    InFlightDiagnostic(DiagnosticEngine &Engine, unsigned idx)
+        : Engine(&Engine), Idx(idx), IsActive(true) {}
+
     InFlightDiagnostic(const InFlightDiagnostic &) = delete;
     InFlightDiagnostic &operator=(const InFlightDiagnostic &) = delete;
     InFlightDiagnostic &operator=(InFlightDiagnostic &&) = delete;
 
+    /// Retrieve the underlying active diagnostic information.
+    detail::ActiveDiagnostic &getActiveDiag() const;
+
+    /// Retrieve the underlying diagnostic.
+    Diagnostic &getDiag() const { return getActiveDiag().Diag; }
+
   public:
     /// Create an active but unattached in-flight diagnostic.
     /// 
     /// The resulting diagnostic can be used as a dummy, accepting the
     /// syntax to add additional information to a diagnostic without
     /// actually emitting a diagnostic.
-    InFlightDiagnostic() : Engine(0), IsActive(true) { }
-    
+    InFlightDiagnostic() : Engine(0), Idx(0), IsActive(true) {}
+
     /// Transfer an in-flight diagnostic to a new object, which is
     /// typically used when returning in-flight diagnostics.
     InFlightDiagnostic(InFlightDiagnostic &&Other)
-      : Engine(Other.Engine), IsActive(Other.IsActive) {
+        : Engine(Other.Engine), Idx(Other.Idx), IsActive(Other.IsActive) {
       Other.IsActive = false;
     }
-    
+
     ~InFlightDiagnostic() {
       if (IsActive)
         flush();
@@ -784,16 +804,12 @@ namespace swift {
     /// Tracks diagnostic behaviors and state
     DiagnosticState state;
 
-    /// The currently active diagnostic, if there is one.
-    std::optional<Diagnostic> ActiveDiagnostic;
-
-    /// Diagnostics wrapped by ActiveDiagnostic, if any.
-    SmallVector<DiagnosticInfo, 2> WrappedDiagnostics;
-    SmallVector<std::vector<DiagnosticArgument>, 4> WrappedDiagnosticArgs;
+    /// The currently active diagnostics.
+    SmallVector<detail::ActiveDiagnostic, 4> ActiveDiagnostics;
 
     /// All diagnostics that have are no longer active but have not yet
     /// been emitted due to an open transaction.
-    SmallVector<Diagnostic, 4> TentativeDiagnostics;
+    SmallVector<detail::ActiveDiagnostic, 4> TentativeDiagnostics;
 
     llvm::BumpPtrAllocator TransactionAllocator;
     /// A set of all strings involved in current transactional chain.
@@ -816,6 +832,9 @@ namespace swift {
     /// emitted once all transactions have closed.
     unsigned TransactionCount = 0;
 
+    /// The number of currently in-flight diagnostics.
+    unsigned NumActiveDiags = 0;
+
     /// For batch mode, use this to know where to output a diagnostic from a
     /// non-primary file. It's any location in the buffer of the current primary
     /// input being compiled.
@@ -851,7 +870,7 @@ namespace swift {
 
   public:
     explicit DiagnosticEngine(SourceManager &SourceMgr)
-        : SourceMgr(SourceMgr), ActiveDiagnostic(),
+        : SourceMgr(SourceMgr), ActiveDiagnostics(),
           TransactionStrings(TransactionAllocator),
           DiagnosticStringsSaver(DiagnosticStringsAllocator) {}
 
@@ -870,6 +889,7 @@ namespace swift {
     }
 
     void flushConsumers() {
+      ASSERT(NumActiveDiags == 0 && "Expected in-flight diags to be flushed");
       for (auto consumer : Consumers)
         consumer->flush();
     }
@@ -1001,10 +1021,9 @@ namespace swift {
     /// \returns An in-flight diagnostic, to which additional information can
     /// be attached.
     InFlightDiagnostic diagnose(SourceLoc Loc, const Diagnostic &D) {
-      assert(!ActiveDiagnostic && "Already have an active diagnostic");
-      ActiveDiagnostic = D;
-      ActiveDiagnostic->setLoc(Loc);
-      return InFlightDiagnostic(*this);
+      auto IFD = beginDiagnostic(D);
+      getActiveDiagnostic(IFD).Diag.setLoc(Loc);
+      return IFD;
     }
     
     /// Emit a diagnostic with the given set of diagnostic arguments.
@@ -1080,10 +1099,9 @@ namespace swift {
     /// \returns An in-flight diagnostic, to which additional information can
     /// be attached.
     InFlightDiagnostic diagnose(const Decl *decl, const Diagnostic &diag) {
-      assert(!ActiveDiagnostic && "Already have an active diagnostic");
-      ActiveDiagnostic = diag;
-      ActiveDiagnostic->setDecl(decl);
-      return InFlightDiagnostic(*this);
+      auto IFD = beginDiagnostic(diag);
+      getActiveDiagnostic(IFD).Diag.setDecl(decl);
+      return IFD;
     }
 
     /// Emit a diagnostic with the given set of diagnostic arguments.
@@ -1137,16 +1155,21 @@ namespace swift {
         DiagnosticFormatOptions FormatOpts = DiagnosticFormatOptions());
 
   private:
+    /// Begins a new in-flight diagnostic.
+    InFlightDiagnostic beginDiagnostic(const Diagnostic &D);
+
+    /// Ends an in-flight diagnostic. Once all in-flight diagnostics have ended,
+    /// they will either be emitted, or captured by an open transaction.
+    void endDiagnostic(const InFlightDiagnostic &D);
+
     /// Called when tentative diagnostic is about to be flushed,
     /// to apply any required transformations e.g. copy string arguments
     /// to extend their lifetime.
     void onTentativeDiagnosticFlush(Diagnostic &diagnostic);
 
-    /// Flush the active diagnostic.
-    void flushActiveDiagnostic();
-    
-    /// Retrieve the active diagnostic.
-    Diagnostic &getActiveDiagnostic() { return *ActiveDiagnostic; }
+    /// Retrieve the stored active diagnostic for a given InFlightDiagnostic.
+    detail::ActiveDiagnostic &
+    getActiveDiagnostic(const InFlightDiagnostic &diag);
 
     /// Generate DiagnosticInfo for a Diagnostic to be passed to consumers.
     std::optional<DiagnosticInfo>
@@ -1162,7 +1185,7 @@ namespace swift {
 
     /// Handle a new diagnostic, which will either be emitted, or added to an
     /// active transaction.
-    void handleDiagnostic(Diagnostic &&diag);
+    void handleDiagnostic(detail::ActiveDiagnostic &&diag);
 
     /// Clear any tentative diagnostics.
     void clearTentativeDiagnostics();
@@ -1291,12 +1314,12 @@ namespace swift {
     }
 
     bool hasErrors() const {
-      ArrayRef<Diagnostic> diagnostics(Engine.TentativeDiagnostics.begin() +
-                                           PrevDiagnostics,
-                                       Engine.TentativeDiagnostics.end());
+      ArrayRef<detail::ActiveDiagnostic> diagnostics(
+          Engine.TentativeDiagnostics.begin() + PrevDiagnostics,
+          Engine.TentativeDiagnostics.end());
 
       for (auto &diagnostic : diagnostics) {
-        auto behavior = Engine.state.determineBehavior(diagnostic);
+        auto behavior = Engine.state.determineBehavior(diagnostic.Diag);
         if (behavior == DiagnosticBehavior::Fatal ||
             behavior == DiagnosticBehavior::Error)
           return true;
@@ -1361,14 +1384,14 @@ namespace swift {
 
       // The first diagnostic is assumed to be the parent. If this is not an
       // error or warning, we'll assert later when trying to add children.
-      Diagnostic &parent = Engine.TentativeDiagnostics[PrevDiagnostics];
+      Diagnostic &parent = Engine.TentativeDiagnostics[PrevDiagnostics].Diag;
 
       // Associate the children with the parent.
       for (auto diag =
                Engine.TentativeDiagnostics.begin() + PrevDiagnostics + 1;
            diag != Engine.TentativeDiagnostics.end(); ++diag) {
-        diag->setIsChildNote(true);
-        parent.addChildNote(std::move(*diag));
+        diag->Diag.setIsChildNote(true);
+        parent.addChildNote(std::move(diag->Diag));
       }
 
       // Erase the children, they'll be emitted alongside their parent.
diff --git a/lib/AST/DiagnosticEngine.cpp b/lib/AST/DiagnosticEngine.cpp
index a26d6eafec562..34c6ec51ab86e 100644
--- a/lib/AST/DiagnosticEngine.cpp
+++ b/lib/AST/DiagnosticEngine.cpp
@@ -205,11 +205,14 @@ static char extractCharBefore(SourceManager &SM, SourceLoc Loc) {
   return chars[0];
 }
 
+detail::ActiveDiagnostic &InFlightDiagnostic::getActiveDiag() const {
+  return Engine->getActiveDiagnostic(*this);
+}
+
 InFlightDiagnostic &InFlightDiagnostic::highlight(SourceRange R) {
   assert(IsActive && "Cannot modify an inactive diagnostic");
   if (Engine && R.isValid())
-    Engine->getActiveDiagnostic()
-        .addRange(toCharSourceRange(Engine->SourceMgr, R));
+    getDiag().addRange(toCharSourceRange(Engine->SourceMgr, R));
   return *this;
 }
 
@@ -217,15 +220,14 @@ InFlightDiagnostic &InFlightDiagnostic::highlightChars(SourceLoc Start,
                                                        SourceLoc End) {
   assert(IsActive && "Cannot modify an inactive diagnostic");
   if (Engine && Start.isValid())
-    Engine->getActiveDiagnostic()
-        .addRange(toCharSourceRange(Engine->SourceMgr, Start, End));
+    getDiag().addRange(toCharSourceRange(Engine->SourceMgr, Start, End));
   return *this;
 }
 
 InFlightDiagnostic &InFlightDiagnostic::highlightChars(CharSourceRange Range) {
   assert(IsActive && "Cannot modify an inactive diagnostic");
   if (Engine && Range.getStart().isValid())
-    Engine->getActiveDiagnostic().addRange(Range);
+    getDiag().addRange(Range);
   return *this;
 }
 
@@ -260,7 +262,7 @@ InFlightDiagnostic &InFlightDiagnostic::fixItRemove(SourceRange R) {
     charRange = CharSourceRange(charRange.getStart(),
                                 charRange.getByteLength()+1);
   }
-  Engine->getActiveDiagnostic().addFixIt(Diagnostic::FixIt(charRange, {}, {}));
+  getDiag().addFixIt(Diagnostic::FixIt(charRange, {}, {}));
   return *this;
 }
 
@@ -270,8 +272,7 @@ InFlightDiagnostic::fixItReplace(SourceRange R, StringRef FormatString,
   auto &SM = Engine->SourceMgr;
   auto charRange = toCharSourceRange(SM, R);
 
-  Engine->getActiveDiagnostic().addFixIt(
-      Diagnostic::FixIt(charRange, FormatString, Args));
+  getDiag().addFixIt(Diagnostic::FixIt(charRange, FormatString, Args));
   return *this;
 }
 
@@ -307,9 +308,8 @@ InFlightDiagnostic::fixItReplaceChars(SourceLoc Start, SourceLoc End,
                                       ArrayRef<DiagnosticArgument> Args) {
   assert(IsActive && "Cannot modify an inactive diagnostic");
   if (Engine && Start.isValid())
-    Engine->getActiveDiagnostic().addFixIt(
-        Diagnostic::FixIt(toCharSourceRange(Engine->SourceMgr, Start, End),
-                          FormatString, Args));
+    getDiag().addFixIt(Diagnostic::FixIt(
+        toCharSourceRange(Engine->SourceMgr, Start, End), FormatString, Args));
   return *this;
 }
 
@@ -350,7 +350,7 @@ SourceLoc DiagnosticEngine::getBestAddImportFixItLoc(SourceFile *SF) const {
 
 InFlightDiagnostic &InFlightDiagnostic::fixItAddImport(StringRef ModuleName) {
   assert(IsActive && "Cannot modify an inactive diagnostic");
-  auto decl = Engine->ActiveDiagnostic->getDecl();
+  auto decl = getDiag().getDecl();
   if (!decl)
     return *this;
 
@@ -428,16 +428,14 @@ InFlightDiagnostic &InFlightDiagnostic::fixItExchange(SourceRange R1,
   auto text1 = SM.extractText(charRange1);
   auto text2 = SM.extractText(charRange2);
 
-  Engine->getActiveDiagnostic().addFixIt(
-      Diagnostic::FixIt(charRange1, "%0", {text2}));
-  Engine->getActiveDiagnostic().addFixIt(
-      Diagnostic::FixIt(charRange2, "%0", {text1}));
+  getDiag().addFixIt(Diagnostic::FixIt(charRange1, "%0", {text2}));
+  getDiag().addFixIt(Diagnostic::FixIt(charRange2, "%0", {text1}));
   return *this;
 }
 
 InFlightDiagnostic &
 InFlightDiagnostic::limitBehavior(DiagnosticBehavior limit) {
-  Engine->getActiveDiagnostic().setBehaviorLimit(limit);
+  getDiag().setBehaviorLimit(limit);
   return *this;
 }
 
@@ -496,30 +494,33 @@ InFlightDiagnostic::wrapIn(const Diagnostic &wrapper) {
   // so we don't get a None return or influence future diagnostics.
   DiagnosticState tempState;
   Engine->state.swap(tempState);
-  llvm::SaveAndRestore<DiagnosticBehavior>
-      limit(Engine->getActiveDiagnostic().BehaviorLimit,
-            DiagnosticBehavior::Unspecified);
 
-  Engine->WrappedDiagnostics.push_back(*Engine->diagnosticInfoForDiagnostic(
-      Engine->getActiveDiagnostic(), /* includeDiagnosticName= */ false));
+  auto &ActiveDiag = getActiveDiag();
+  auto &Diag = ActiveDiag.Diag;
+
+  llvm::SaveAndRestore<DiagnosticBehavior> limit(
+      Diag.BehaviorLimit, DiagnosticBehavior::Unspecified);
+
+  ActiveDiag.WrappedDiagnostics.push_back(*Engine->diagnosticInfoForDiagnostic(
+      Diag, /* includeDiagnosticName= */ false));
 
   Engine->state.swap(tempState);
 
-  auto &wrapped = Engine->WrappedDiagnostics.back();
+  auto &wrapped = ActiveDiag.WrappedDiagnostics.back();
 
   // Copy and update its arg list.
-  Engine->WrappedDiagnosticArgs.emplace_back(wrapped.FormatArgs);
-  wrapped.FormatArgs = Engine->WrappedDiagnosticArgs.back();
+  ActiveDiag.WrappedDiagnosticArgs.emplace_back(wrapped.FormatArgs);
+  wrapped.FormatArgs = ActiveDiag.WrappedDiagnosticArgs.back();
 
   // Overwrite the ID and arguments with those from the wrapper.
-  Engine->getActiveDiagnostic().ID = wrapper.ID;
-  Engine->getActiveDiagnostic().Args = wrapper.Args;
+  Diag.ID = wrapper.ID;
+  Diag.Args = wrapper.Args;
   // Intentionally keeping the original GroupID here
 
   // Set the argument to the diagnostic being wrapped.
   ASSERT(wrapper.getArgs().front().getKind() ==
          DiagnosticArgumentKind::Diagnostic);
-  Engine->getActiveDiagnostic().Args.front() = &wrapped;
+  Diag.Args.front() = &wrapped;
 
   return *this;
 }
@@ -530,7 +531,7 @@ void InFlightDiagnostic::flush() {
   
   IsActive = false;
   if (Engine)
-    Engine->flushActiveDiagnostic();
+    Engine->endDiagnostic(*this);
 }
 
 void Diagnostic::addChildNote(Diagnostic &&D) {
@@ -1354,32 +1355,48 @@ void DiagnosticState::updateFor(DiagnosticBehavior behavior) {
   previousBehavior = behavior;
 }
 
-void DiagnosticEngine::flushActiveDiagnostic() {
-  assert(ActiveDiagnostic && "No active diagnostic to flush");
-  handleDiagnostic(std::move(*ActiveDiagnostic));
-  ActiveDiagnostic.reset();
+InFlightDiagnostic DiagnosticEngine::beginDiagnostic(const Diagnostic &D) {
+  unsigned idx = ActiveDiagnostics.size();
+  ActiveDiagnostics.emplace_back(D);
+  NumActiveDiags += 1;
+  return InFlightDiagnostic(*this, idx);
+}
+
+void DiagnosticEngine::endDiagnostic(const InFlightDiagnostic &D) {
+  // Decrement the number of active diagnostics. We wait until all in-flight
+  // diagnostics have ended to ensure a FIFO ordering.
+  ASSERT(NumActiveDiags > 0 && "Unbalanced call to endDiagnostic");
+  NumActiveDiags -= 1;
+  if (NumActiveDiags > 0)
+    return;
+
+  for (auto &D : ActiveDiagnostics)
+    handleDiagnostic(std::move(D));
+
+  ActiveDiagnostics.clear();
+}
+
+detail::ActiveDiagnostic &
+DiagnosticEngine::getActiveDiagnostic(const InFlightDiagnostic &diag) {
+  return ActiveDiagnostics[diag.Idx];
 }
 
-void DiagnosticEngine::handleDiagnostic(Diagnostic &&diag) {
+void DiagnosticEngine::handleDiagnostic(detail::ActiveDiagnostic &&diag) {
   if (TransactionCount == 0) {
-    emitDiagnostic(diag);
-    WrappedDiagnostics.clear();
-    WrappedDiagnosticArgs.clear();
+    emitDiagnostic(diag.Diag);
   } else {
-    onTentativeDiagnosticFlush(diag);
+    onTentativeDiagnosticFlush(diag.Diag);
     TentativeDiagnostics.emplace_back(std::move(diag));
   }
 }
 
 void DiagnosticEngine::clearTentativeDiagnostics() {
   TentativeDiagnostics.clear();
-  WrappedDiagnostics.clear();
-  WrappedDiagnosticArgs.clear();
 }
 
 void DiagnosticEngine::emitTentativeDiagnostics() {
   for (auto &diag : TentativeDiagnostics) {
-    emitDiagnostic(diag);
+    emitDiagnostic(diag.Diag);
   }
   clearTentativeDiagnostics();
 }
@@ -1410,11 +1427,15 @@ DiagnosticEngine::diagnosticInfoForDiagnostic(const Diagnostic &diagnostic,
     loc = decl->getLoc();
 
     // If the location of the decl is invalid still, try to pretty-print the
-    // declaration into a buffer and capture the source location there.
+    // declaration into a buffer and capture the source location there. Make
+    // sure we don't have an active request running since printing AST can
+    // kick requests that may themselves emit diagnostics. This won't help the
+    // underlying cycle, but it at least stops us from overflowing the stack.
     if (loc.isInvalid()) {
-      loc = evaluateOrDefault(
-          decl->getASTContext().evaluator, PrettyPrintDeclRequest{decl},
-          SourceLoc());
+      PrettyPrintDeclRequest req(decl);
+      auto &eval = decl->getASTContext().evaluator;
+      if (!eval.hasActiveRequest(req))
+        loc = evaluateOrDefault(eval, req, SourceLoc());
     }
   }
 
diff --git a/lib/Sema/CSApply.cpp b/lib/Sema/CSApply.cpp
index 50925acd9a1c2..84d810a10fda1 100644
--- a/lib/Sema/CSApply.cpp
+++ b/lib/Sema/CSApply.cpp
@@ -5092,9 +5092,6 @@ namespace {
           // If the property is settable, we don't know whether the
           // user wanted the getter or setter. Provide notes for each.
           if (isSettable) {
-            // Flush the primary diagnostic. We have notes to add.
-            primaryDiag.flush();
-
             // Add notes for the getter and setter, respectively.
             de.diagnose(modifierLoc, diag::expr_selector_add_modifier, false,
                         var)
diff --git a/lib/Sema/CSDiagnostics.cpp b/lib/Sema/CSDiagnostics.cpp
index 525c8ec622840..e1ad24ab0f54c 100644
--- a/lib/Sema/CSDiagnostics.cpp
+++ b/lib/Sema/CSDiagnostics.cpp
@@ -1923,7 +1923,6 @@ bool MissingOptionalUnwrapFailure::diagnoseAsError() {
                                                       "#default value#"
                                                       "> }");
         }
-        diag.flush();
 
         offerDefaultValueUnwrapFixIt(varDecl->getDeclContext(), initializer);
         offerForceUnwrapFixIt(initializer);
@@ -3150,7 +3149,7 @@ void ContextualFailure::tryFixIts(InFlightDiagnostic &diagnostic) const {
   if (tryIntegerCastFixIts(diagnostic))
     return;
 
-  if (tryProtocolConformanceFixIt(diagnostic))
+  if (tryProtocolConformanceFixIt())
     return;
 
   if (tryTypeCoercionFixIt(diagnostic))
@@ -3521,8 +3520,7 @@ bool ContextualFailure::tryTypeCoercionFixIt(
   return false;
 }
 
-bool ContextualFailure::tryProtocolConformanceFixIt(
-    InFlightDiagnostic &diagnostic) const {
+bool ContextualFailure::tryProtocolConformanceFixIt() const {
   auto innermostTyCtx = getDC()->getInnermostTypeContext();
   if (!innermostTyCtx)
     return false;
@@ -3556,8 +3554,6 @@ bool ContextualFailure::tryProtocolConformanceFixIt(
   if (!shouldOfferFixIt)
     return false;
 
-  diagnostic.flush();
-
   // Let's build a list of protocols that the context does not conform to.
   SmallVector<std::string, 8> missingProtoTypeStrings;
   SmallVector<ProtocolDecl *, 8> missingProtocols;
@@ -4090,7 +4086,6 @@ bool SubscriptMisuseFailure::diagnoseAsError() {
   } else {
     diag.fixItReplace(SourceRange(memberExpr->getDotLoc(), memberExpr->getLoc()), "[<#index#>]");
   }
-  diag.flush();
 
   if (auto overload = getOverloadChoiceIfAvailable(locator)) {
     emitDiagnosticAt(overload->choice.getDecl(), diag::kind_declared_here,
@@ -5355,8 +5350,6 @@ bool MissingArgumentsFailure::diagnoseAsError() {
     diag.fixItInsertAfter(getRawAnchor().getEndLoc(), fixIt.str());
   }
 
-  diag.flush();
-
   if (auto selectedOverload = getCalleeOverloadChoiceIfAvailable(locator)) {
     if (auto *decl = selectedOverload->choice.getDeclOrNull()) {
       emitDiagnosticAt(decl, diag::decl_declared_here, decl);
@@ -5724,8 +5717,6 @@ bool MissingArgumentsFailure::diagnoseInvalidTupleDestructuring() const {
     diagnostic.fixItRemove(TE->getLParenLoc()).fixItRemove(TE->getRParenLoc());
   }
 
-  diagnostic.flush();
-
   // Add a note which points to the overload choice location.
   emitDiagnosticAt(decl, diag::decl_declared_here, decl);
   return true;
@@ -6126,8 +6117,6 @@ bool ExtraneousArgumentsFailure::diagnoseAsError() {
       }
     }
 
-    diag.flush();
-
     // If all of the parameters are anonymous, let's point out references
     // to make it explicit where parameters are used in complex closure body,
     // which helps in situations where braces are missing for potential inner
@@ -8621,8 +8610,6 @@ void MissingRawRepresentableInitFailure::fixIt(
           .fixItInsert(range.Start, rawReprObjType->getString() + "(rawValue: ")
           .fixItInsertAfter(range.End, ")");
     } else if (valueObjType) {
-      diagnostic.flush();
-
       std::string fixItBefore = RawReprType->getString() + "(rawValue: ";
       std::string fixItAfter;
 
diff --git a/lib/Sema/CSDiagnostics.h b/lib/Sema/CSDiagnostics.h
index 5c65d8a23c067..db63643637066 100644
--- a/lib/Sema/CSDiagnostics.h
+++ b/lib/Sema/CSDiagnostics.h
@@ -726,7 +726,7 @@ class ContextualFailure : public FailureDiagnostic {
 
   /// Try to add a fix-it to conform the decl context (if it's a type) to the
   /// protocol
-  bool tryProtocolConformanceFixIt(InFlightDiagnostic &diagnostic) const;
+  bool tryProtocolConformanceFixIt() const;
 
 private:
   Type resolve(Type rawType) const {
diff --git a/lib/Sema/ImportResolution.cpp b/lib/Sema/ImportResolution.cpp
index 0b4df8782715f..e14ef37dfb046 100644
--- a/lib/Sema/ImportResolution.cpp
+++ b/lib/Sema/ImportResolution.cpp
@@ -1159,7 +1159,6 @@ CheckInconsistentAccessLevelOnImport::evaluate(
       error.fixItInsert(implicitImport->getStartLoc(),
                         diag::inconsistent_implicit_access_level_on_import_fixit,
                         otherAccessLevel);
-      error.flush();
       diags.diagnose(implicitImport,
                      diag::inconsistent_implicit_access_level_on_import_silence);
     }
@@ -1352,7 +1351,6 @@ ScopedImportLookupRequest::evaluate(Evaluator &evaluator,
 
     emittedDiag->fixItReplace(SourceRange(import->getKindLoc()),
                               getImportKindString(*actualKind));
-    emittedDiag->flush();
 
     if (decls.size() == 1)
       ctx.Diags.diagnose(decls.front(), diag::decl_declared_here,
diff --git a/lib/Sema/TypeCheckAccess.cpp b/lib/Sema/TypeCheckAccess.cpp
index df58d18e1b2c3..56c702a1e0a59 100644
--- a/lib/Sema/TypeCheckAccess.cpp
+++ b/lib/Sema/TypeCheckAccess.cpp
@@ -363,12 +363,10 @@ void AccessControlCheckerBase::checkTypeAccess(
 static void highlightOffendingType(InFlightDiagnostic &diag,
                                    const TypeRepr *complainRepr) {
   if (!complainRepr) {
-    diag.flush();
     return;
   }
 
   diag.highlight(complainRepr->getSourceRange());
-  diag.flush();
 
   if (auto *declRefTR = dyn_cast<DeclRefTypeRepr>(complainRepr)) {
     const ValueDecl *VD = declRefTR->getBoundDecl();
@@ -2480,7 +2478,7 @@ class DeclAvailabilityChecker : public DeclVisitor<DeclAvailabilityChecker> {
                     );
     if (refRange.isValid())
       diag.highlight(refRange);
-    diag.flush();
+
     PGD->diagnose(diag::name_declared_here, PGD->getName());
   }
 
diff --git a/lib/Sema/TypeCheckDeclPrimary.cpp b/lib/Sema/TypeCheckDeclPrimary.cpp
index a290483e08c72..bb64bc738022b 100644
--- a/lib/Sema/TypeCheckDeclPrimary.cpp
+++ b/lib/Sema/TypeCheckDeclPrimary.cpp
@@ -2036,7 +2036,6 @@ static void diagnoseChangesByAccessNote(
     if (fixItLoc.isInvalid())
       fixItLoc = attr->getRangeWithAt().Start;
   }
-  diag.flush();
 
   if (!fixItLoc)
     fixItLoc = VD->getAttributeInsertionLoc(true);
@@ -4028,7 +4027,6 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
                                  nominal->getDeclaredType());
         diag.highlight(extTypeRepr->getSourceRange());
         if (firstNominalIsNotMostSpecific) {
-          diag.flush();
           Type mostSpecificProtocol = extTypeNominal->getDeclaredType();
           ED->diagnose(diag::composition_in_extended_type_alternative,
                        mostSpecificProtocol)
diff --git a/lib/Sema/TypeCheckPattern.cpp b/lib/Sema/TypeCheckPattern.cpp
index 7b32dc99b585f..52d8705d7b072 100644
--- a/lib/Sema/TypeCheckPattern.cpp
+++ b/lib/Sema/TypeCheckPattern.cpp
@@ -1010,7 +1010,6 @@ void repairTupleOrAssociatedValuePatternIfApplicable(
         auto trailingParen = SourceRange(enumElementInnerPat->getEndLoc());
         diag.fixItRemove(leadingParen).fixItRemove(trailingParen);
       }
-      diag.flush();
       addDeclNote();
       enumElementInnerPat = semantic;
     } else {
diff --git a/lib/Sema/TypeCheckProtocol.cpp b/lib/Sema/TypeCheckProtocol.cpp
index a1350bfd42a99..825de49b1eccb 100644
--- a/lib/Sema/TypeCheckProtocol.cpp
+++ b/lib/Sema/TypeCheckProtocol.cpp
@@ -4049,16 +4049,14 @@ static void diagnoseProtocolStubFixit(
 
     // Issue diagnostics for witness types.
     if (auto MissingTypeWitness = dyn_cast<AssociatedTypeDecl>(VD)) {
-      std::optional<InFlightDiagnostic> diag;
       if (isa<BuiltinTupleDecl>(DC->getSelfNominalTypeDecl())) {
         auto expectedTy = getTupleConformanceTypeWitness(DC, MissingTypeWitness);
-        diag.emplace(Diags.diagnose(MissingTypeWitness, diag::no_witnesses_type_tuple,
-                                    MissingTypeWitness, expectedTy));
+        Diags.diagnose(MissingTypeWitness, diag::no_witnesses_type_tuple,
+                       MissingTypeWitness, expectedTy);
       } else {
-        diag.emplace(Diags.diagnose(MissingTypeWitness, diag::no_witnesses_type,
-                                    MissingTypeWitness));
+        Diags.diagnose(MissingTypeWitness, diag::no_witnesses_type,
+                       MissingTypeWitness);
       }
-      diag.value().flush();
       continue;
     }
 
@@ -4208,7 +4206,6 @@ void ConformanceChecker::checkNonFinalClassWitness(ValueDecl *requirement,
             // If the main diagnostic is emitted on the conformance, we want to
             // attach the fix-it to the note that shows where the initializer is
             // defined.
-            fixItDiag.value().flush();
             fixItDiag.emplace(diags.diagnose(ctor, diag::decl_declared_here,
                                              ctor));
           }
@@ -4387,7 +4384,6 @@ ConformanceChecker::resolveWitnessViaLookup(ValueDecl *requirement) {
             if (diagLoc == witness->getLoc()) {
               fixDeclarationName(diag, witness, requirement->getName());
             } else {
-              diag.flush();
               diags.diagnose(witness, diag::decl_declared_here, witness);
             }
           }
@@ -4568,7 +4564,6 @@ ConformanceChecker::resolveWitnessViaLookup(ValueDecl *requirement) {
             if (diagLoc == witness->getLoc()) {
               addOptionalityFixIts(adjustments, ctx, witness, diag);
             } else {
-              diag.flush();
               diags.diagnose(witness, diag::decl_declared_here, witness);
             }
           }
@@ -5661,7 +5656,6 @@ void ConformanceChecker::resolveValueWitnesses() {
               // If the main diagnostic is emitted on the conformance, we want
               // to attach the fix-it to the note that shows where the
               // witness is defined.
-              fixItDiag.value().flush();
               fixItDiag.emplace(
                   witness->diagnose(diag::make_decl_objc, witness));
             }
@@ -5681,7 +5675,6 @@ void ConformanceChecker::resolveValueWitnesses() {
               // If the main diagnostic is emitted on the conformance, we want
               // to attach the fix-it to the note that shows where the
               // witness is defined.
-              fixItDiag.value().flush();
               fixItDiag.emplace(
                   witness->diagnose(diag::make_decl_objc, witness));
             }
@@ -5701,7 +5694,6 @@ void ConformanceChecker::resolveValueWitnesses() {
               // If the main diagnostic is emitted on the conformance, we want
               // to attach the fix-it to the note that shows where the
               // witness is defined.
-              fixItDiag.value().flush();
               fixItDiag.emplace(
                   witness->diagnose(diag::make_decl_objc, witness));
             }
diff --git a/lib/Serialization/Deserialization.cpp b/lib/Serialization/Deserialization.cpp
index 40663997609e3..5705760de92ef 100644
--- a/lib/Serialization/Deserialization.cpp
+++ b/lib/Serialization/Deserialization.cpp
@@ -255,9 +255,7 @@ ModularizationError::diagnose(const ModuleFile *MF,
     llvm_unreachable("Unhandled ModularizationError::Kind in switch.");
   };
 
-  auto inFlight = diagnoseError(errorKind);
-  inFlight.limitBehavior(limit);
-  inFlight.flush();
+  diagnoseError(errorKind).limitBehavior(limit);
 
   // We could pass along the `path` information through notes.
   // However, for a top-level decl a path would just duplicate the
diff --git a/validation-test/compiler_crashers_2/1a9cf8aaa2cfa83f.swift b/validation-test/compiler_crashers_2_fixed/1a9cf8aaa2cfa83f.swift
similarity index 83%
rename from validation-test/compiler_crashers_2/1a9cf8aaa2cfa83f.swift
rename to validation-test/compiler_crashers_2_fixed/1a9cf8aaa2cfa83f.swift
index 92a703da54eb3..b08add06cc2fb 100644
--- a/validation-test/compiler_crashers_2/1a9cf8aaa2cfa83f.swift
+++ b/validation-test/compiler_crashers_2_fixed/1a9cf8aaa2cfa83f.swift
@@ -1,5 +1,5 @@
 // {"kind":"typecheck","signature":"diagnoseInvalidObjCName(swift::ValueDecl*, swift::ObjCAttr*)","signatureAssert":"Assertion failed: (!ActiveDiagnostic && \"Already have an active diagnostic\"), function diagnose"}
-// RUN: not --crash %target-swift-frontend -typecheck %s
+// RUN: not %target-swift-frontend -typecheck %s
 // REQUIRES: objc_interop
 @objcMembers class a open extension a {
   func 0.0
diff --git a/validation-test/compiler_crashers_2/56edea24a97933f.swift b/validation-test/compiler_crashers_2_fixed/56edea24a97933f.swift
similarity index 84%
rename from validation-test/compiler_crashers_2/56edea24a97933f.swift
rename to validation-test/compiler_crashers_2_fixed/56edea24a97933f.swift
index f6762eba2d498..f64af92306ad6 100644
--- a/validation-test/compiler_crashers_2/56edea24a97933f.swift
+++ b/validation-test/compiler_crashers_2_fixed/56edea24a97933f.swift
@@ -1,5 +1,5 @@
 // {"kind":"typecheck","signature":"swift::isRepresentableInObjC(swift::VarDecl const*, swift::ObjCReason)","signatureAssert":"Assertion failed: (!ActiveDiagnostic && \"Already have an active diagnostic\"), function diagnose"}
-// RUN: not --crash %target-swift-frontend -typecheck %s
+// RUN: not %target-swift-frontend -typecheck %s
 // REQUIRES: objc_interop
 class a class b open extension b {
   @objc c : a
diff --git a/validation-test/compiler_crashers_2/5cc8bc3069f97958.swift b/validation-test/compiler_crashers_2_fixed/5cc8bc3069f97958.swift
similarity index 86%
rename from validation-test/compiler_crashers_2/5cc8bc3069f97958.swift
rename to validation-test/compiler_crashers_2_fixed/5cc8bc3069f97958.swift
index e80667ec63bb3..996cb30444deb 100644
--- a/validation-test/compiler_crashers_2/5cc8bc3069f97958.swift
+++ b/validation-test/compiler_crashers_2_fixed/5cc8bc3069f97958.swift
@@ -1,5 +1,5 @@
 // {"kind":"typecheck","signature":"(anonymous namespace)::TypeResolver::resolveImplicitlyUnwrappedOptionalType(swift::ImplicitlyUnwrappedOptionalTypeRepr*, swift::TypeResolutionOptions, bool)","signatureAssert":"Assertion failed: (!ActiveDiagnostic && \"Already have an active diagnostic\"), function diagnose"}
-// RUN: not --crash %target-swift-frontend -typecheck %s
+// RUN: not %target-swift-frontend -typecheck %s
 {
   enum a: b! {
   }
diff --git a/validation-test/compiler_crashers_2/64915463735bcf5b.swift b/validation-test/compiler_crashers_2_fixed/64915463735bcf5b.swift
similarity index 86%
rename from validation-test/compiler_crashers_2/64915463735bcf5b.swift
rename to validation-test/compiler_crashers_2_fixed/64915463735bcf5b.swift
index ea0f8f0111370..67ffb2847a5c7 100644
--- a/validation-test/compiler_crashers_2/64915463735bcf5b.swift
+++ b/validation-test/compiler_crashers_2_fixed/64915463735bcf5b.swift
@@ -1,4 +1,4 @@
 // {"kind":"typecheck","signature":"swift::Evaluator::diagnoseCycle(swift::ActiveRequest const&)","signatureAssert":"Assertion failed: (!ActiveDiagnostic && \"Already have an active diagnostic\"), function diagnose"}
-// RUN: not --crash %target-swift-frontend -typecheck %s
+// RUN: not %target-swift-frontend -typecheck %s
 // REQUIRES: OS=macosx
 import Distributed typealias DefaultDistributedActorSystem = LocalTestingDistributedActorSystem distributed actor a{distributed...
diff --git a/validation-test/compiler_crashers_2/66e337320b1924c.swift b/validation-test/compiler_crashers_2_fixed/66e337320b1924c.swift
similarity index 82%
rename from validation-test/compiler_crashers_2/66e337320b1924c.swift
rename to validation-test/compiler_crashers_2_fixed/66e337320b1924c.swift
index 6d712726de2f7..8e41eee816eda 100644
--- a/validation-test/compiler_crashers_2/66e337320b1924c.swift
+++ b/validation-test/compiler_crashers_2_fixed/66e337320b1924c.swift
@@ -1,3 +1,3 @@
 // {"kind":"typecheck","signature":"swift::ProtocolRequiresClassRequest::diagnoseCycle(swift::DiagnosticEngine&) const","signatureAssert":"Assertion failed: (!ActiveDiagnostic && \"Already have an active diagnostic\"), function diagnose"}
-// RUN: not --crash %target-swift-frontend -typecheck %s
+// RUN: not %target-swift-frontend -typecheck %s
 struct b let b c a = b protocol a : a
diff --git a/validation-test/compiler_crashers_2/72eed0e8ff21c1a.swift b/validation-test/compiler_crashers_2_fixed/72eed0e8ff21c1a.swift
similarity index 85%
rename from validation-test/compiler_crashers_2/72eed0e8ff21c1a.swift
rename to validation-test/compiler_crashers_2_fixed/72eed0e8ff21c1a.swift
index f4581a132109e..d5639d345e040 100644
--- a/validation-test/compiler_crashers_2/72eed0e8ff21c1a.swift
+++ b/validation-test/compiler_crashers_2_fixed/72eed0e8ff21c1a.swift
@@ -1,5 +1,5 @@
 // {"kind":"typecheck","signature":"isParamListRepresentableInLanguage(swift::AbstractFunctionDecl const*, swift::ParameterList const*, swift::ObjCReason)","signatureAssert":"Assertion failed: (!ActiveDiagnostic && \"Already have an active diagnostic\"), function diagnose"}
-// RUN: not --crash %target-swift-frontend -typecheck %s
+// RUN: not %target-swift-frontend -typecheck %s
 // REQUIRES: objc_interop
 class a open extension a {
   @objc b(_)
diff --git a/validation-test/compiler_crashers_2/7aa9d3699dddb337.swift b/validation-test/compiler_crashers_2_fixed/7aa9d3699dddb337.swift
similarity index 84%
rename from validation-test/compiler_crashers_2/7aa9d3699dddb337.swift
rename to validation-test/compiler_crashers_2_fixed/7aa9d3699dddb337.swift
index 7d32e52511c7b..ef7871d8ee0f6 100644
--- a/validation-test/compiler_crashers_2/7aa9d3699dddb337.swift
+++ b/validation-test/compiler_crashers_2_fixed/7aa9d3699dddb337.swift
@@ -1,5 +1,5 @@
 // {"kind":"typecheck","signature":"swift::PatternTypeRequest::evaluate(swift::Evaluator&, swift::ContextualPattern) const","signatureAssert":"Assertion failed: (!ActiveDiagnostic && \"Already have an active diagnostic\"), function diagnose"}
-// RUN: not --crash %target-swift-frontend -typecheck %s
+// RUN: not %target-swift-frontend -typecheck %s
 // REQUIRES: objc_interop
 @objcMembers class a open extension a {
   var b
diff --git a/validation-test/compiler_crashers_2/82fe033c6bdba61.swift b/validation-test/compiler_crashers_2_fixed/82fe033c6bdba61.swift
similarity index 82%
rename from validation-test/compiler_crashers_2/82fe033c6bdba61.swift
rename to validation-test/compiler_crashers_2_fixed/82fe033c6bdba61.swift
index 68e2502839039..ea43bff0c0236 100644
--- a/validation-test/compiler_crashers_2/82fe033c6bdba61.swift
+++ b/validation-test/compiler_crashers_2_fixed/82fe033c6bdba61.swift
@@ -1,5 +1,5 @@
 // {"kind":"typecheck","signature":"swift::DerivedConformance::deriveDecodable(swift::ValueDecl*)","signatureAssert":"Assertion failed: (!ActiveDiagnostic && \"Already have an active diagnostic\"), function diagnose"}
-// RUN: not --crash %target-swift-frontend -typecheck %s
+// RUN: not %target-swift-frontend -typecheck %s
 struct a {
   var
   b, c : Codable {
diff --git a/validation-test/compiler_crashers_2/a81ff5cc2d29ef15.swift b/validation-test/compiler_crashers_2_fixed/a81ff5cc2d29ef15.swift
similarity index 84%
rename from validation-test/compiler_crashers_2/a81ff5cc2d29ef15.swift
rename to validation-test/compiler_crashers_2_fixed/a81ff5cc2d29ef15.swift
index ee5783b1a903d..8f9d57cb13841 100644
--- a/validation-test/compiler_crashers_2/a81ff5cc2d29ef15.swift
+++ b/validation-test/compiler_crashers_2_fixed/a81ff5cc2d29ef15.swift
@@ -1,5 +1,5 @@
 // {"kind":"typecheck","signature":"swift::IsStaticRequest::evaluate(swift::Evaluator&, swift::FuncDecl*) const","signatureAssert":"Assertion failed: (!ActiveDiagnostic && \"Already have an active diagnostic\"), function diagnose"}
-// RUN: not --crash %target-swift-frontend -typecheck %s
+// RUN: not %target-swift-frontend -typecheck %s
 // REQUIRES: objc_interop
 @objcMembers class a open extension a {
   ...
diff --git a/validation-test/compiler_crashers_2/ad9313b914fb2.swift b/validation-test/compiler_crashers_2_fixed/ad9313b914fb2.swift
similarity index 81%
rename from validation-test/compiler_crashers_2/ad9313b914fb2.swift
rename to validation-test/compiler_crashers_2_fixed/ad9313b914fb2.swift
index 8d25aa55a222f..6c56558edbc85 100644
--- a/validation-test/compiler_crashers_2/ad9313b914fb2.swift
+++ b/validation-test/compiler_crashers_2_fixed/ad9313b914fb2.swift
@@ -1,5 +1,5 @@
 // {"kind":"typecheck","signature":"swift::Evaluator::diagnoseCycle(swift::ActiveRequest const&)","signatureAssert":"Assertion failed: (!ActiveDiagnostic && \"Already have an active diagnostic\"), function diagnose"}
-// RUN: not --crash %target-swift-frontend -typecheck %s
+// RUN: not %target-swift-frontend -typecheck %s
 class a
   let _ b = a
   class b : b.c
diff --git a/validation-test/compiler_crashers_2/bafa48a4eecbfb62.swift b/validation-test/compiler_crashers_2_fixed/bafa48a4eecbfb62.swift
similarity index 87%
rename from validation-test/compiler_crashers_2/bafa48a4eecbfb62.swift
rename to validation-test/compiler_crashers_2_fixed/bafa48a4eecbfb62.swift
index 506b7134048c2..38aef2d70c875 100644
--- a/validation-test/compiler_crashers_2/bafa48a4eecbfb62.swift
+++ b/validation-test/compiler_crashers_2_fixed/bafa48a4eecbfb62.swift
@@ -1,5 +1,5 @@
 // {"kind":"typecheck","signature":"diagnoseUnknownType(swift::TypeResolution const&, swift::Type, swift::SourceRange, swift::DeclRefTypeRepr*, swift::optionset::OptionSet<swift::NameLookupFlags, unsigned int>)","signatureAssert":"Assertion failed: (!ActiveDiagnostic && \"Already have an active diagnostic\"), function diagnose"}
-// RUN: not --crash %target-swift-frontend -typecheck %s
+// RUN: not %target-swift-frontend -typecheck %s
 // REQUIRES: objc_interop
 class b open extension b {
   @objc c : a
diff --git a/validation-test/compiler_crashers_2/bf67776f769fa0f1.swift b/validation-test/compiler_crashers_2_fixed/bf67776f769fa0f1.swift
similarity index 84%
rename from validation-test/compiler_crashers_2/bf67776f769fa0f1.swift
rename to validation-test/compiler_crashers_2_fixed/bf67776f769fa0f1.swift
index 0bc770bef97af..ad88a55f6ba3d 100644
--- a/validation-test/compiler_crashers_2/bf67776f769fa0f1.swift
+++ b/validation-test/compiler_crashers_2_fixed/bf67776f769fa0f1.swift
@@ -1,5 +1,5 @@
 // {"kind":"typecheck","signature":"(anonymous namespace)::TypeResolver::resolveType(swift::TypeRepr*, swift::TypeResolutionOptions)","signatureAssert":"Assertion failed: (!ActiveDiagnostic && \"Already have an active diagnostic\"), function diagnose"}
-// RUN: not --crash %target-swift-frontend -typecheck %s
+// RUN: not %target-swift-frontend -typecheck %s
 // REQUIRES: objc_interop
 class a open extension a {
   @objc b : _
diff --git a/validation-test/compiler_crashers_2/db15a23c5f8aeff.swift b/validation-test/compiler_crashers_2_fixed/db15a23c5f8aeff.swift
similarity index 83%
rename from validation-test/compiler_crashers_2/db15a23c5f8aeff.swift
rename to validation-test/compiler_crashers_2_fixed/db15a23c5f8aeff.swift
index 91e705fd10182..6d49f28bbc024 100644
--- a/validation-test/compiler_crashers_2/db15a23c5f8aeff.swift
+++ b/validation-test/compiler_crashers_2_fixed/db15a23c5f8aeff.swift
@@ -1,5 +1,5 @@
 // {"kind":"typecheck","original":"36a5bbda","signature":"swift::SuperclassDeclRequest::diagnoseCycle(swift::DiagnosticEngine&) const","signatureAssert":"Assertion failed: (!ActiveDiagnostic && \"Already have an active diagnostic\"), function diagnose"}
-// RUN: not --crash %target-swift-frontend -typecheck %s
+// RUN: not %target-swift-frontend -typecheck %s
 {
   class a: a {
   }
diff --git a/validation-test/compiler_crashers_2/f8296a9a293c6ae7.swift b/validation-test/compiler_crashers_2_fixed/f8296a9a293c6ae7.swift
similarity index 85%
rename from validation-test/compiler_crashers_2/f8296a9a293c6ae7.swift
rename to validation-test/compiler_crashers_2_fixed/f8296a9a293c6ae7.swift
index ac8da3cce6fc9..2d875f2714084 100644
--- a/validation-test/compiler_crashers_2/f8296a9a293c6ae7.swift
+++ b/validation-test/compiler_crashers_2_fixed/f8296a9a293c6ae7.swift
@@ -1,5 +1,5 @@
 // {"kind":"typecheck","signature":"(anonymous namespace)::TypeResolver::resolveCompositionType(swift::CompositionTypeRepr*, swift::TypeResolutionOptions)","signatureAssert":"Assertion failed: (!ActiveDiagnostic && \"Already have an active diagnostic\"), function diagnose"}
-// RUN: not --crash %target-swift-frontend -typecheck %s
+// RUN: not %target-swift-frontend -typecheck %s
 // REQUIRES: objc_interop
 class a open extension a {
   @objc b : Int &
diff --git a/validation-test/compiler_crashers_2/fca26dd570bcdf1c.swift b/validation-test/compiler_crashers_2_fixed/fca26dd570bcdf1c.swift
similarity index 85%
rename from validation-test/compiler_crashers_2/fca26dd570bcdf1c.swift
rename to validation-test/compiler_crashers_2_fixed/fca26dd570bcdf1c.swift
index 395d470a2d3b0..ac6ae7e300572 100644
--- a/validation-test/compiler_crashers_2/fca26dd570bcdf1c.swift
+++ b/validation-test/compiler_crashers_2_fixed/fca26dd570bcdf1c.swift
@@ -1,5 +1,5 @@
 // {"kind":"typecheck","signature":"(anonymous namespace)::TypeResolver::resolveVarargType(swift::VarargTypeRepr*, swift::TypeResolutionOptions)","signatureAssert":"Assertion failed: (!ActiveDiagnostic && \"Already have an active diagnostic\"), function diagnose"}
-// RUN: not --crash %target-swift-frontend -typecheck %s
+// RUN: not %target-swift-frontend -typecheck %s
 // REQUIRES: objc_interop
 class a open extension a {
   @objc b : Int...
diff --git a/validation-test/compiler_crashers_2/ff105cea796d442f.swift b/validation-test/compiler_crashers_2_fixed/ff105cea796d442f.swift
similarity index 86%
rename from validation-test/compiler_crashers_2/ff105cea796d442f.swift
rename to validation-test/compiler_crashers_2_fixed/ff105cea796d442f.swift
index 7792cf2aea778..c47fa2fdd7fe8 100644
--- a/validation-test/compiler_crashers_2/ff105cea796d442f.swift
+++ b/validation-test/compiler_crashers_2_fixed/ff105cea796d442f.swift
@@ -1,5 +1,5 @@
 // {"kind":"typecheck","signature":"swift::InFlightDiagnostic swift::diagnoseAttrWithRemovalFixIt<swift::Diag<>&>(swift::Decl const*, swift::DeclAttribute const*, swift::Diag<>&)","signatureAssert":"Assertion failed: (!ActiveDiagnostic && \"Already have an active diagnostic\"), function diagnose"}
-// RUN: not --crash %target-swift-frontend -typecheck %s
+// RUN: not %target-swift-frontend -typecheck %s
 // REQUIRES: objc_interop
 class a open extension a {
   @objc class b