RequirementMachine: Allow RequirementMachine::isConcreteType() and ::getCanonicalTypeInContext() to be used with protocol connected components

Author: slavapestov

lib/AST/RequirementMachine/GenericSignatureQueries.cpp

@@ -156,9 +156,14 @@ getSuperclassBound(Type depType,
   return props->getSuperclassBound(genericParams, term, Map);
 }
 
-bool RequirementMachine::isConcreteType(Type depType) const {
+/// Unlike the other queries, we have occasion to call this on a requirement
+/// machine for a protocol connected component as well as a top-level
+/// generic signature, so plumb through the protocol to use for the root
+/// `Self` generic parameter here.
+bool RequirementMachine::isConcreteType(Type depType,
+                                        const ProtocolDecl *proto) const {
   auto term = Context.getMutableTermForType(depType->getCanonicalType(),
-                                            /*proto=*/nullptr);
+                                            proto);
   System.simplify(term);
   verify(term);
 
@@ -169,11 +174,16 @@ bool RequirementMachine::isConcreteType(Type depType) const {
   return props->isConcreteType();
 }
 
+/// Unlike the other queries, we have occasion to call this on a requirement
+/// machine for a protocol connected component as well as a top-level
+/// generic signature, so plumb through the protocol to use for the root
+/// `Self` generic parameter here.
 Type RequirementMachine::
 getConcreteType(Type depType,
-                TypeArrayView<GenericTypeParamType> genericParams) const {
+                TypeArrayView<GenericTypeParamType> genericParams,
+                const ProtocolDecl *proto) const {
   auto term = Context.getMutableTermForType(depType->getCanonicalType(),
-                                            /*proto=*/nullptr);
+                                            proto);
   System.simplify(term);
   verify(term);
 

lib/AST/RequirementMachine/RequirementMachine.cpp

@@ -172,6 +172,10 @@ RequirementMachine::initWithProtocolWrittenRequirements(
                          SmallVector<StructuralRequirement, 4>> protos) {
   FrontendStatsTracer tracer(Stats, "build-rewrite-system");
 
+  // For RequirementMachine::verify() when called by generic signature queries;
+  // We have a single valid generic parameter at depth 0, index 0.
+  Params.push_back(component[0]->getSelfInterfaceType()->getCanonicalType());
+
   if (Dump) {
     llvm::dbgs() << "Adding protocols";
     for (auto *proto : component) {

lib/AST/RequirementMachine/RequirementMachine.h

@@ -142,9 +142,11 @@ class RequirementMachine final {
   GenericSignature::RequiredProtocols getRequiredProtocols(Type depType) const;
   Type getSuperclassBound(Type depType,
                           TypeArrayView<GenericTypeParamType> genericParams) const;
-  bool isConcreteType(Type depType) const;
+  bool isConcreteType(Type depType,
+                      const ProtocolDecl *proto=nullptr) const;
   Type getConcreteType(Type depType,
-                       TypeArrayView<GenericTypeParamType> genericParams) const;
+                       TypeArrayView<GenericTypeParamType> genericParams,
+                       const ProtocolDecl *proto=nullptr) const;
   bool areSameTypeParameterInContext(Type depType1, Type depType2) const;
   bool isCanonicalTypeInContext(Type type) const;
   Type getCanonicalTypeInContext(Type type,

lib/AST/RequirementMachine/RequirementMachineRequests.cpp

@@ -119,8 +119,6 @@ RequirementMachine::computeMinimalProtocolRequirements() {
 
   assert(protos.size() > 0 &&
          "Not a protocol connected component rewrite system");
-  assert(Params.empty() &&
-         "Not a protocol connected component rewrite system");
 
   System.minimizeRewriteSystem();