Merge pull request swiftlang#80327 from slavapestov/fix-useless-method

Small fixes for new abstract conformance representation

Author: slavapestov

include/swift/AST/TypeTransform.h

@@ -154,7 +154,7 @@ case TypeKind::Id:
         return *result;
 
       auto subMap = opaque->getSubstitutions();
-      auto newSubMap = asDerived().transformSubMap(subMap);
+      auto newSubMap = asDerived().transformSubstitutionMap(subMap);
       if (newSubMap == subMap)
         return t;
       if (!newSubMap)
@@ -177,7 +177,7 @@ case TypeKind::Id:
       auto subMap = env->getOuterSubstitutions();
       auto uuid = env->getOpenedExistentialUUID();
 
-      auto newSubMap = asDerived().transformSubMap(subMap);
+      auto newSubMap = asDerived().transformSubstitutionMap(subMap);
       if (newSubMap == subMap)
         return t;
       if (!newSubMap)
@@ -259,7 +259,7 @@ case TypeKind::Id:
       }
 
       auto oldSubMap = boxTy->getSubstitutions();
-      auto newSubMap = asDerived().transformSubMap(oldSubMap);
+      auto newSubMap = asDerived().transformSubstitutionMap(oldSubMap);
       if (oldSubMap && !newSubMap)
         return Type();
       changed |= (oldSubMap != newSubMap);
@@ -281,7 +281,7 @@ case TypeKind::Id:
         return fnTy;
 
       auto updateSubs = [&](SubstitutionMap &subs) -> bool {
-        auto newSubs = asDerived().transformSubMap(subs);
+        auto newSubs = asDerived().transformSubstitutionMap(subs);
         if (subs && !newSubs)
           return false;
         if (subs == newSubs)
@@ -1052,7 +1052,7 @@ case TypeKind::Id:
 
   // If original was non-empty and transformed is empty, we're
   // signaling failure, that is, a Type() return from doIt().
-  SubstitutionMap transformSubMap(SubstitutionMap subs) {
+  SubstitutionMap transformSubstitutionMap(SubstitutionMap subs) {
     if (subs.empty())
       return subs;
 

lib/AST/ASTDumper.cpp

@@ -5527,6 +5527,12 @@ class PrintConformance : public PrintBase {
       assert(conformance.isAbstract());
 
       printHead("abstract_conformance", ASTNodeColor, label);
+
+      PrintOptions PO;
+      PO.OpaqueReturnTypePrinting =
+          PrintOptions::OpaqueReturnTypePrintingMode::StableReference;
+
+      printTypeField(conformance.getType(), Label::always("type"), PO);
       printReferencedDeclField(conformance.getProtocol(),
                                Label::always("protocol"));
       printFoot();

lib/AST/ProtocolConformanceRef.cpp

@@ -93,23 +93,24 @@ ProtocolConformanceRef::subst(Type origType, InFlightSubstitution &IFS) const {
   if (isPack())
     return getPack()->subst(IFS);
 
-  // Handle abstract conformances below:
+  ASSERT(isAbstract());
+  auto *proto = getProtocol();
 
   // If the type is an opaque archetype, the conformance will remain abstract,
   // unless we're specifically substituting opaque types.
-  if (auto origArchetype = origType->getAs<ArchetypeType>()) {
-    if (!IFS.shouldSubstituteOpaqueArchetypes()
-        && isa<OpaqueTypeArchetypeType>(origArchetype)) {
-      return *this;
+  if (auto origArchetype = origType->getAs<OpaqueTypeArchetypeType>()) {
+    if (!IFS.shouldSubstituteOpaqueArchetypes()) {
+      return forAbstract(origType.subst(IFS), proto);
     }
   }
 
+  // FIXME: Handle local archetypes as above!
+
   // Otherwise, compute the substituted type.
   auto substType = origType.subst(IFS);
 
-  auto *proto = getProtocol();
-
   // If the type is an existential, it must be self-conforming.
+  // FIXME: This feels like it's in the wrong place.
   if (substType->isExistentialType()) {
     auto optConformance =
         lookupConformance(substType, proto, /*allowMissing=*/true);
@@ -119,7 +120,7 @@ ProtocolConformanceRef::subst(Type origType, InFlightSubstitution &IFS) const {
     return ProtocolConformanceRef::forInvalid();
   }
 
-  // Check the conformance map.
+  // Local conformance lookup into the substitution map.
   // FIXME: Pack element level?
   return IFS.lookupConformance(origType->getCanonicalType(), substType, proto,
                                /*level=*/0);
@@ -128,24 +129,20 @@ ProtocolConformanceRef::subst(Type origType, InFlightSubstitution &IFS) const {
 ProtocolConformanceRef ProtocolConformanceRef::mapConformanceOutOfContext() const {
   if (isConcrete()) {
     return getConcrete()->subst(
-        [](SubstitutableType *type) -> Type {
-          if (auto *archetypeType = type->getAs<ArchetypeType>())
-            return archetypeType->getInterfaceType();
-          return type;
-        },
+        MapTypeOutOfContext(),
         MakeAbstractConformanceForGenericType(),
         SubstFlags::PreservePackExpansionLevel |
         SubstFlags::SubstitutePrimaryArchetypes);
   } else if (isPack()) {
     return getPack()->subst(
-        [](SubstitutableType *type) -> Type {
-          if (auto *archetypeType = type->getAs<ArchetypeType>())
-            return archetypeType->getInterfaceType();
-          return type;
-        },
+        MapTypeOutOfContext(),
         MakeAbstractConformanceForGenericType(),
         SubstFlags::PreservePackExpansionLevel |
         SubstFlags::SubstitutePrimaryArchetypes);
+  } else if (isAbstract()) {
+    auto *abstract = getAbstract();
+    return forAbstract(abstract->getType()->mapTypeOutOfContext(),
+                       abstract->getProtocol());
   }
 
   return *this;
@@ -266,6 +263,15 @@ ProtocolConformanceRef::getAssociatedConformance(Type conformingType,
     return conformance->getAssociatedConformance(assocType, protocol);
   }
 
+  auto computeSubjectType = [&](Type conformingType) -> Type {
+    return assocType.transformRec(
+      [&](TypeBase *t) -> std::optional<Type> {
+        if (isa<GenericTypeParamType>(t))
+          return conformingType;
+        return std::nullopt;
+      });
+  };
+
   // An associated conformance of an archetype might be known to be
   // a concrete conformance, if the subject type is fixed to a concrete
   // type in the archetype's generic signature. We don't actually have
@@ -276,15 +282,8 @@ ProtocolConformanceRef::getAssociatedConformance(Type conformingType,
   // conformances where they store their subject types, we can also
   // cache the lookups inside the abstract conformance instance too.
   if (auto archetypeType = conformingType->getAs<ArchetypeType>()) {
-    conformingType = archetypeType->getInterfaceType();
     auto *genericEnv = archetypeType->getGenericEnvironment();
-
-    auto subjectType = assocType.transformRec(
-      [&](TypeBase *t) -> std::optional<Type> {
-        if (isa<GenericTypeParamType>(t))
-          return conformingType;
-        return std::nullopt;
-      });
+    auto subjectType = computeSubjectType(archetypeType->getInterfaceType());
 
     return lookupConformance(
         genericEnv->mapTypeIntoContext(subjectType),
@@ -296,12 +295,8 @@ ProtocolConformanceRef::getAssociatedConformance(Type conformingType,
   // signature of the substitution (or in the case of type variables,
   // we have no visibility into constraints). See the parallel hack
   // to handle this in SubstitutionMap::lookupConformance().
-  CONDITIONAL_ASSERT(conformingType->isTypeParameter() ||
-                     conformingType->isTypeVariableOrMember() ||
-                     conformingType->is<UnresolvedType>() ||
-                     conformingType->is<PlaceholderType>());
-
-  return ProtocolConformanceRef::forAbstract(conformingType, protocol);
+  auto subjectType = computeSubjectType(conformingType);
+  return ProtocolConformanceRef::forAbstract(subjectType, protocol);
 }
 
 /// Check of all types used by the conformance are canonical.

lib/AST/SubstitutionMap.cpp

@@ -381,7 +381,7 @@ SubstitutionMap SubstitutionMap::subst(InFlightSubstitution &IFS) const {
         ProtocolConformanceRef(conformance.getConcrete()->subst(IFS)));
     } else {
       auto origType = req.getFirstType();
-      auto substType = origType.subst(*this, IFS.getOptions());
+      auto substType = origType.subst(*this);
 
       newConformances.push_back(conformance.subst(substType, IFS));
     }

lib/AST/TypeSubstitution.cpp

@@ -1108,37 +1108,23 @@ ProtocolConformanceRef swift::substOpaqueTypesWithUnderlyingTypes(
 ProtocolConformanceRef ReplaceOpaqueTypesWithUnderlyingTypes::
 operator()(CanType maybeOpaqueType, Type replacementType,
            ProtocolDecl *protocol) const {
-  auto abstractRef = ProtocolConformanceRef::forAbstract(maybeOpaqueType, protocol);
-  
   auto archetype = dyn_cast<OpaqueTypeArchetypeType>(maybeOpaqueType);
-  if (!archetype) {
-    if (maybeOpaqueType->isTypeParameter() ||
-        maybeOpaqueType->is<ArchetypeType>())
-      return abstractRef;
-    
-    // SIL type lowering may have already substituted away the opaque type, in
-    // which case we'll end up "substituting" the same type.
-    if (maybeOpaqueType->isEqual(replacementType)) {
-      return lookupConformance(replacementType, protocol);
-    }
-    
-    llvm_unreachable("origType should have been an opaque type or type parameter");
-  }
+  if (!archetype)
+    return lookupConformance(replacementType, protocol);
 
   auto *genericEnv = archetype->getGenericEnvironment();
   auto *decl = genericEnv->getOpaqueTypeDecl();
   auto outerSubs = genericEnv->getOuterSubstitutions();
 
   auto substitutionKind = shouldPerformSubstitution(decl);
-  if (substitutionKind == OpaqueSubstitutionKind::DontSubstitute) {
-    return abstractRef;
-  }
+  if (substitutionKind == OpaqueSubstitutionKind::DontSubstitute)
+    return lookupConformance(replacementType, protocol);
 
   auto subs = decl->getUniqueUnderlyingTypeSubstitutions();
   // If the body of the opaque decl providing decl has not been type checked we
   // don't have a underlying substitution.
   if (!subs.has_value())
-    return abstractRef;
+    return lookupConformance(replacementType, protocol);
 
   // Apply the underlying type substitutions to the interface type of the
   // archetype in question. This will map the inner generic signature of the
@@ -1159,7 +1145,7 @@ operator()(CanType maybeOpaqueType, Type replacementType,
               return true;
             return false;
           }))
-    return abstractRef;
+    return lookupConformance(replacementType, protocol);
 
   // Then apply the substitutions from the root opaque archetype, to specialize
   // for its type arguments. We perform this substitution after checking for
@@ -1168,7 +1154,8 @@ operator()(CanType maybeOpaqueType, Type replacementType,
   auto substTy = partialSubstTy.subst(outerSubs);
 
   auto partialSubstRef =
-      abstractRef.subst(archetype->getInterfaceType(), *subs);
+      subs->lookupConformance(archetype->getInterfaceType()->getCanonicalType(),
+                              protocol);
   auto substRef =
       partialSubstRef.subst(partialSubstTy, outerSubs);
 
@@ -1181,7 +1168,7 @@ operator()(CanType maybeOpaqueType, Type replacementType,
       // type back to the caller. This substitution will fail at runtime
       // instead.
       if (!alreadySeen->insert(seenKey).second) {
-        return abstractRef;
+        return lookupConformance(replacementType, protocol);
       }
 
       auto res = ::substOpaqueTypesWithUnderlyingTypesRec(

test/Frontend/debug-generic-signatures.swift

@@ -98,9 +98,9 @@ struct Generic<T> {}
 // CHECK-NEXT:   (assoc_conformance type="Self" proto="Escapable"
 // CHECK-NEXT:     (builtin_conformance type="Generic<T>" protocol="Escapable"))
 // CHECK-NEXT:   (assoc_conformance type="Self.A" proto="Copyable"
-// CHECK-NEXT:     (abstract_conformance protocol="Copyable"))
+// CHECK-NEXT:     (abstract_conformance type="T" protocol="Copyable"))
 // CHECK-NEXT:   (assoc_conformance type="Self.A" proto="Escapable"
-// CHECK-NEXT:     (abstract_conformance protocol="Escapable"))
+// CHECK-NEXT:     (abstract_conformance type="T" protocol="Escapable"))
 // CHECK-NEXT:   (requirement "T" conforms_to "P1"))
 extension Generic: P1 where T: P1 {
     typealias A = T
@@ -123,9 +123,9 @@ class Super<T, U> {}
 // CHECK-NEXT:   (assoc_conformance type="Self" proto="Escapable"
 // CHECK-NEXT:     (builtin_conformance type="Super<T, U>" protocol="Escapable"))
 // CHECK-NEXT:   (assoc_conformance type="Self.A" proto="P2"
-// CHECK-NEXT:     (abstract_conformance protocol="P2"))
+// CHECK-NEXT:     (abstract_conformance type="T" protocol="P2"))
 // CHECK-NEXT:   (assoc_conformance type="Self.B" proto="P2"
-// CHECK-NEXT:     (abstract_conformance protocol="P2"))
+// CHECK-NEXT:     (abstract_conformance type="T" protocol="P2"))
 // CHECK-NEXT:   (requirement "T" conforms_to "P2")
 // CHECK-NEXT:   (requirement "U" conforms_to "P2"))
 extension Super: P2 where T: P2, U: P2 {
@@ -177,9 +177,9 @@ extension Super: P2 where T: P2, U: P2 {
 // CHECK-NEXT:       (assoc_conformance type="Self" proto="Escapable"
 // CHECK-NEXT:         (builtin_conformance type="Super<T, U>" protocol="Escapable"))
 // CHECK-NEXT:       (assoc_conformance type="Self.A" proto="P2"
-// CHECK-NEXT:         (abstract_conformance protocol="P2"))
+// CHECK-NEXT:         (abstract_conformance type="T" protocol="P2"))
 // CHECK-NEXT:       (assoc_conformance type="Self.B" proto="P2"
-// CHECK-NEXT:         (abstract_conformance protocol="P2"))
+// CHECK-NEXT:         (abstract_conformance type="T" protocol="P2"))
 // CHECK-NEXT:       (requirement "T" conforms_to "P2")
 // CHECK-NEXT:       (requirement "U" conforms_to "P2"))))
 class Sub: Super<NonRecur, Recur> {}

validation-test/SILGen/SwiftUI/opaque_result_type_erasure.swift

@@ -0,0 +1,27 @@
+// RUN: %target-swift-frontend -emit-silgen %s -target %target-cpu-apple-macosx11 -swift-version 5
+
+// REQUIRES: objc_interop
+// REQUIRES: OS=macosx
+
+import SwiftUI
+
+struct MyView: View {
+    @State private var isPresented = false
+
+    var body: some View {
+        NavigationView {
+            Form {
+                subsection
+            }
+            .listStyle(DefaultListStyle())
+            .navigationTitle(Text(""))
+            .sheet(isPresented: $isPresented,
+                   onDismiss: { },
+                   content: { Text("") })
+        }
+    }
+
+    private var subsection: some View {
+        Text("")
+    }
+}