[RequirementMachine] Separate setting the explicit bit and the requirement

ID for a rewrite rule.

Author: hborla

lib/AST/RequirementMachine/HomotopyReduction.cpp

@@ -184,7 +184,7 @@ void RewriteSystem::propagateExplicitBits() {
       for (unsigned ruleID : rulesInEmptyContext) {
         auto &rule = getRule(ruleID);
         if (!rule.isPermanent() && !rule.isExplicit())
-          rule.markExplicit(None);
+          rule.markExplicit();
       }
     }
   }
@@ -220,7 +220,7 @@ void RewriteSystem::propagateRedundantRequirementIDs() {
           replacement.dump(llvm::dbgs());
         }
 
-        replacement.markExplicit(requirementID);
+        replacement.setRequirementID(requirementID);
       }
     }
   }

lib/AST/RequirementMachine/RewriteSystem.cpp

@@ -500,7 +500,8 @@ bool RewriteSystem::addExplicitRule(MutableTerm lhs, MutableTerm rhs,
                                     SmallVectorImpl<RequirementError> &errors) {
   bool added = addRule(std::move(lhs), std::move(rhs));
   if (added) {
-    Rules.back().markExplicit(requirementID);
+    Rules.back().markExplicit();
+    Rules.back().setRequirementID(requirementID);
   } else if (requirementID.hasValue()) {
     auto req = WrittenRequirements[requirementID.getValue()];
     errors.push_back(
@@ -742,13 +743,11 @@ void RewriteSystem::computeRedundantRequirementDiagnostics(
   for (unsigned ruleID : indices(getRules())) {
     auto &rule = getRules()[ruleID];
 
-    if (!rule.isExplicit() && !rule.isPermanent() && !rule.isRedundant() &&
+    if (!rule.getRequirementID().hasValue() &&
+        !rule.isPermanent() && !rule.isRedundant() &&
         isInMinimizationDomain(rule.getLHS().getRootProtocol()))
       impliedRequirements.insert(ruleID);
 
-    if (!rule.isExplicit())
-      continue;
-
     auto requirementID = rule.getRequirementID();
     if (!requirementID.hasValue())
       continue;

lib/AST/RequirementMachine/RewriteSystem.h

@@ -107,6 +107,11 @@ class Rule final {
     return requirementID;
   }
 
+  void setRequirementID(Optional<unsigned> requirementID) {
+    assert(!getRequirementID().hasValue());
+    this->requirementID = requirementID;
+  }
+
   Optional<Symbol> isPropertyRule() const;
 
   const ProtocolDecl *isProtocolConformanceRule() const;
@@ -176,12 +181,9 @@ class Rule final {
     Permanent = true;
   }
 
-  void markExplicit(Optional<unsigned> requirementID) {
-    assert((!Explicit || requirementID.hasValue()) &&
-           "Rule is already explicit");
-    assert(!Permanent &&
+  void markExplicit() {
+    assert(!Explicit && !Permanent &&
            "Permanent and explicit are mutually exclusive");
-    this->requirementID = requirementID;
     Explicit = true;
   }