---

yaml
---
r: 343531
b: refs/heads/master-rebranch
c: 7897ab8
h: refs/heads/master
i:
  343529: 3f04900
  343527: b3478a3

Author: jckarter

[refs]

@@ -1455,7 +1455,7 @@ refs/tags/swift-DEVELOPMENT-SNAPSHOT-2019-08-02-a: ddd2b2976aa9bfde5f20fe37f6bd2
 refs/tags/swift-DEVELOPMENT-SNAPSHOT-2019-08-03-a: 171cc166f2abeb5ca2a4003700a8a78a108bd300
 refs/heads/benlangmuir-patch-1: baaebaf39d52f3bf36710d4fe40cf212e996b212
 refs/heads/i-do-redeclare: 8c4e6d5de5c1e3f0a2cedccf319df713ea22c48e
-refs/heads/master-rebranch: 624ad4fcb056378c112345266ffeb03f269fe0bc
+refs/heads/master-rebranch: 7897ab8674b84f9422e13e4d6e301f5eaf527e43
 refs/heads/rdar-53901732: 9bd06af3284e18a109cdbf9aa59d833b24eeca7b
 refs/heads/revert-26776-subst-always-returns-a-type: 1b8e18fdd391903a348970a4c848995d4cdd789c
 refs/heads/tensorflow-merge: 8b854f62f80d4476cb383d43c4aac2001dde3cec

branches/master-rebranch/lib/Sema/TypeCheckProtocol.cpp

@@ -1927,9 +1927,29 @@ SourceLoc OptionalAdjustment::getOptionalityLoc(TypeRepr *tyR) const {
   return SourceLoc();
 }
 
+namespace {
+/// Describes the position for optional adjustment made to a witness.
+///
+/// This is used by the following diagnostics:
+/// 1) 'err_protocol_witness_optionality',
+/// 2) 'warn_protocol_witness_optionality'
+/// 3) 'protocol_witness_optionality_conflict'
+enum class OptionalAdjustmentPosition : unsigned {
+  /// The type of a variable.
+  VarType = 0,
+  /// The result type of something.
+  Result = 1,
+  /// The parameter type of something.
+  Param = 2,
+  /// The parameter types of something.
+  MultipleParam = 3,
+  /// Both return and parameter adjustments.
+  ParamAndReturn = 4,
+};
+} // end anonymous namespace
+
 /// Classify the provided optionality issues for use in diagnostics.
-/// FIXME: Enumify this
-static unsigned classifyOptionalityIssues(
+static OptionalAdjustmentPosition classifyOptionalityIssues(
     const SmallVectorImpl<OptionalAdjustment> &adjustments,
     ValueDecl *requirement) {
   unsigned numParameterAdjustments = 0;
@@ -1942,21 +1962,20 @@ static unsigned classifyOptionalityIssues(
   }
 
   if (hasNonParameterAdjustment) {
-    // Both return and parameter adjustments.
     if (numParameterAdjustments > 0)
-      return 4;
+      return OptionalAdjustmentPosition::ParamAndReturn;
 
-    // The type of a variable.
     if (isa<VarDecl>(requirement))
-      return 0;
+      return OptionalAdjustmentPosition::VarType;
 
-    // The result type of something.
-    return 1;
+    return OptionalAdjustmentPosition::Result;
   }
 
   // Only parameter adjustments.
   assert(numParameterAdjustments > 0 && "No adjustments?");
-  return numParameterAdjustments == 1 ? 2 : 3;
+  return numParameterAdjustments == 1
+             ? OptionalAdjustmentPosition::Param
+             : OptionalAdjustmentPosition::MultipleParam;
 }
 
 static void addOptionalityFixIts(
@@ -2076,10 +2095,11 @@ diagnoseMatch(ModuleDecl *module, NormalProtocolConformance *conformance,
 
   case MatchKind::OptionalityConflict: {
     auto &adjustments = match.OptionalAdjustments;
-    auto diag = diags.diagnose(match.Witness, 
+    auto issues =
+        static_cast<unsigned>(classifyOptionalityIssues(adjustments, req));
+    auto diag = diags.diagnose(match.Witness,
                                diag::protocol_witness_optionality_conflict,
-                               classifyOptionalityIssues(adjustments, req),
-                               withAssocTypes);
+                               issues, withAssocTypes);
     addOptionalityFixIts(adjustments,
                          match.Witness->getASTContext(),
                          match.Witness,
@@ -3167,14 +3187,14 @@ ConformanceChecker::resolveWitnessViaLookup(ValueDecl *requirement) {
           auto &diags = ctx.Diags;
           {
             SourceLoc diagLoc = getLocForDiagnosingWitness(conformance,witness);
+            auto issues = static_cast<unsigned>(
+                classifyOptionalityIssues(adjustments, requirement));
             auto diag = diags.diagnose(
                 diagLoc,
                 hasAnyError(adjustments)
-                  ? diag::err_protocol_witness_optionality
-                  : diag::warn_protocol_witness_optionality,
-                classifyOptionalityIssues(adjustments, requirement),
-                witness->getFullName(),
-                proto->getFullName());
+                    ? diag::err_protocol_witness_optionality
+                    : diag::warn_protocol_witness_optionality,
+                issues, witness->getFullName(), proto->getFullName());
             if (diagLoc == witness->getLoc()) {
               addOptionalityFixIts(adjustments, ctx, witness, diag);
             } else {