Merge pull request #41256 from slavapestov/rqm-remove-merged-assoc-types

RequirementMachine: Remove merged associated types

Author: slavapestov

include/swift/Basic/LangOptions.h

@@ -498,9 +498,6 @@ namespace swift {
     ASTVerifierOverrideKind ASTVerifierOverride =
         ASTVerifierOverrideKind::NoOverride;
 
-    /// Enables merged associated type support, which might go away.
-    bool RequirementMachineMergedAssociatedTypes = false;
-
     /// Enables dumping rewrite systems from the requirement machine.
     bool DumpRequirementMachine = false;
 

include/swift/Option/FrontendOptions.td

@@ -355,14 +355,6 @@ def requirement_machine_max_concrete_nesting : Joined<["-"], "requirement-machin
   Flags<[FrontendOption, HelpHidden, DoesNotAffectIncrementalBuild]>,
   HelpText<"Set the maximum concrete type nesting depth before giving up">;
 
-def disable_requirement_machine_merged_associated_types : Flag<["-"], "disable-requirement-machine-merged-associated-types">,
-  Flags<[FrontendOption, HelpHidden, DoesNotAffectIncrementalBuild]>,
-  HelpText<"Disable merged associated types">;
-
-def enable_requirement_machine_merged_associated_types : Flag<["-"], "enable-requirement-machine-merged-associated-types">,
-  Flags<[FrontendOption, HelpHidden, DoesNotAffectIncrementalBuild]>,
-  HelpText<"Enable merged associated types">;
-
 def debug_generic_signatures : Flag<["-"], "debug-generic-signatures">,
   HelpText<"Debug generic signatures">;
 

lib/AST/RequirementMachine/ConcreteTypeWitness.cpp

@@ -200,7 +200,7 @@ void PropertyMap::concretizeNestedTypesFromConcreteParent(
 
     // We only infer conditional requirements in top-level generic signatures,
     // not in protocol requirement signatures.
-    if (key.getRootProtocols().empty())
+    if (key.getRootProtocol() == nullptr)
       inferConditionalRequirements(concrete, substitutions);
   }
 }

lib/AST/RequirementMachine/GenericSignatureQueries.cpp

@@ -227,12 +227,10 @@ RequirementMachine::getLongestValidPrefix(const MutableTerm &term) const {
 
       auto conformsTo = props->getConformsTo();
 
-      for (const auto *proto : symbol.getProtocols()) {
-        // T.[P:A] is valid iff T conforms to P.
-        if (std::find(conformsTo.begin(), conformsTo.end(), proto)
-              == conformsTo.end())
-          return prefix;
-      }
+      // T.[P:A] is valid iff T conforms to P.
+      if (std::find(conformsTo.begin(), conformsTo.end(), symbol.getProtocol())
+            == conformsTo.end())
+        return prefix;
 
       break;
     }
@@ -720,7 +718,7 @@ void RequirementMachine::verify(const MutableTerm &term) const {
         continue;
 
       case Symbol::Kind::AssociatedType:
-        erased.add(Symbol::forProtocol(symbol.getProtocols()[0], Context));
+        erased.add(Symbol::forProtocol(symbol.getProtocol(), Context));
         break;
 
       case Symbol::Kind::Name:

lib/AST/RequirementMachine/HomotopyReduction.cpp

@@ -651,10 +651,7 @@ RewriteSystem::getMinimizedProtocolRules() const {
       continue;
     }
 
-    auto domain = rule.getLHS()[0].getProtocols();
-    assert(domain.size() == 1);
-
-    const auto *proto = domain[0];
+    const auto *proto = rule.getLHS().begin()->getProtocol();
     if (std::find(Protos.begin(), Protos.end(), proto) != Protos.end())
       rules[proto].push_back(ruleID);
   }
@@ -734,7 +731,7 @@ void RewriteSystem::verifyMinimizedRules(
     const auto &rule = getRule(ruleID);
 
     // Ignore the rewrite rule if it is not part of our minimization domain.
-    if (!isInMinimizationDomain(rule.getLHS().getRootProtocols()))
+    if (!isInMinimizationDomain(rule.getLHS().getRootProtocol()))
       continue;
 
     // Note that sometimes permanent rules can be simplified, but they can never

lib/AST/RequirementMachine/InterfaceType.cpp

@@ -177,26 +177,26 @@ AssociatedTypeDecl *RewriteContext::getAssociatedTypeForSymbol(Symbol symbol) {
   // The associated type An' is then the canonical associated type
   // representative of the associated type symbol [P0&...&Pn:A].
   //
-  for (auto *proto : symbol.getProtocols()) {
-    auto checkOtherAssocType = [&](AssociatedTypeDecl *otherAssocType) {
-      otherAssocType = otherAssocType->getAssociatedTypeAnchor();
+  auto *proto = symbol.getProtocol();
 
-      if (otherAssocType->getName() == name &&
-          (assocType == nullptr ||
-           TypeDecl::compare(otherAssocType->getProtocol(),
-                             assocType->getProtocol()) < 0)) {
-        assocType = otherAssocType;
-      }
-    };
+  auto checkOtherAssocType = [&](AssociatedTypeDecl *otherAssocType) {
+    otherAssocType = otherAssocType->getAssociatedTypeAnchor();
 
-    for (auto *otherAssocType : proto->getAssociatedTypeMembers()) {
-      checkOtherAssocType(otherAssocType);
+    if (otherAssocType->getName() == name &&
+        (assocType == nullptr ||
+         TypeDecl::compare(otherAssocType->getProtocol(),
+                           assocType->getProtocol()) < 0)) {
+      assocType = otherAssocType;
     }
+  };
 
-    for (auto *inheritedProto : getInheritedProtocols(proto)) {
-      for (auto *otherAssocType : inheritedProto->getAssociatedTypeMembers()) {
-        checkOtherAssocType(otherAssocType);
-      }
+  for (auto *otherAssocType : proto->getAssociatedTypeMembers()) {
+    checkOtherAssocType(otherAssocType);
+  }
+
+  for (auto *inheritedProto : getInheritedProtocols(proto)) {
+    for (auto *otherAssocType : inheritedProto->getAssociatedTypeMembers()) {
+      checkOtherAssocType(otherAssocType);
     }
   }
 
@@ -318,8 +318,8 @@ getTypeForSymbolRange(const Symbol *begin, const Symbol *end, Type root,
 #ifndef NDEBUG
       // Ensure that the domain of the suffix contains P.
       if (iter + 1 < end) {
-        auto protos = (iter + 1)->getProtocols();
-        assert(std::find(protos.begin(), protos.end(), symbol.getProtocol()));
+        auto proto = (iter + 1)->getProtocol();
+        assert(proto == symbol.getProtocol());
       }
 #endif
       continue;
@@ -350,10 +350,9 @@ getTypeForSymbolRange(const Symbol *begin, const Symbol *end, Type root,
       // of protocols that the prefix conforms to.
   #ifndef NDEBUG
       auto conformsTo = props->getConformsTo();
-      for (auto *otherProto : symbol.getProtocols()) {
-        assert(std::find(conformsTo.begin(), conformsTo.end(), otherProto)
-               != conformsTo.end());
-      }
+      assert(std::find(conformsTo.begin(), conformsTo.end(),
+                       symbol.getProtocol())
+             != conformsTo.end());
   #endif
 
       assocType = props->getAssociatedType(symbol.getName());