GSB: Simplify addConditionalRequirements()

Author: slavapestov

include/swift/AST/DiagnosticsSema.def

@@ -2428,9 +2428,6 @@ WARNING(missing_protocol_refinement, none,
         "protocol %0 should be declared to refine %1 due to a same-type constraint on 'Self'",
         (ProtocolDecl *, ProtocolDecl *))
 
-ERROR(unsupported_recursive_requirements, none,
-      "requirement involves recursion that is not currently supported", ())
-
 ERROR(same_type_conflict,none,
       "%select{generic parameter |protocol |}0%1 cannot be equal to both "
       "%2 and %3", (unsigned, Type, Type, Type))

include/swift/AST/GenericSignatureBuilder.h

@@ -342,10 +342,8 @@ class GenericSignatureBuilder {
                                    UnresolvedHandlingKind unresolvedHandling);
 
   /// Add any conditional requirements from the given conformance.
-  ///
-  /// \returns \c true if an error occurred, \c false if not.
-  bool addConditionalRequirements(ProtocolConformanceRef conformance,
-                                  ModuleDecl *inferForModule, SourceLoc loc);
+  void addConditionalRequirements(ProtocolConformanceRef conformance,
+                                  ModuleDecl *inferForModule);
 
   /// Resolve the conformance of the given type to the given protocol when the
   /// potential archetype is known to be equivalent to a concrete type.

lib/AST/GenericSignatureBuilder.cpp

@@ -2488,28 +2488,17 @@ ConstraintResult GenericSignatureBuilder::handleUnresolvedRequirement(
   llvm_unreachable("unhandled handling");
 }
 
-bool GenericSignatureBuilder::addConditionalRequirements(
-    ProtocolConformanceRef conformance, ModuleDecl *inferForModule,
-    SourceLoc loc) {
+void GenericSignatureBuilder::addConditionalRequirements(
+    ProtocolConformanceRef conformance, ModuleDecl *inferForModule) {
   // Abstract conformances don't have associated decl-contexts/modules, but also
   // don't have conditional requirements.
   if (conformance.isConcrete()) {
-    if (auto condReqs = conformance.getConditionalRequirementsIfAvailable()) {
-      auto source = FloatingRequirementSource::forInferred(nullptr);
-      for (auto requirement : *condReqs) {
-        addRequirement(requirement, source, inferForModule);
-        ++NumConditionalRequirementsAdded;
-      }
-    } else {
-      if (loc.isValid())
-        Diags.diagnose(loc, diag::unsupported_recursive_requirements);
-
-      Impl->HadAnyError = true;
-      return true;
+    auto source = FloatingRequirementSource::forInferred(nullptr);
+    for (auto requirement : conformance.getConditionalRequirements()) {
+      addRequirement(requirement, source, inferForModule);
+      ++NumConditionalRequirementsAdded;
     }
   }
-
-  return false;
 }
 
 const RequirementSource *
@@ -2576,9 +2565,7 @@ GenericSignatureBuilder::resolveConcreteConformance(ResolvedType type,
       });
 
   if (hasExplicitSource) {
-    if (addConditionalRequirements(conformance, /*inferForModule=*/nullptr,
-                                   concreteSource->getLoc()))
-      return nullptr;
+    addConditionalRequirements(conformance, /*inferForModule=*/nullptr);
   }
 
   return concreteSource;
@@ -2619,9 +2606,7 @@ const RequirementSource *GenericSignatureBuilder::resolveSuperConformance(
     });
 
   if (hasExplicitSource) {
-    if (addConditionalRequirements(conformance, /*inferForModule=*/nullptr,
-                                   superclassSource->getLoc()))
-      return nullptr;
+    addConditionalRequirements(conformance, /*inferForModule=*/nullptr);
   }
 
   return superclassSource;
@@ -4833,9 +4818,7 @@ ConstraintResult GenericSignatureBuilder::addTypeRequirement(
         if (conformance) {
           // Only infer conditional requirements from explicit sources.
           if (!source.isDerived()) {
-            if (addConditionalRequirements(conformance, inferForModule,
-                                           source.getLoc()))
-              return ConstraintResult::Conflicting;
+            addConditionalRequirements(conformance, inferForModule);
           }
         }
       }