RequirementMachine: Preliminary implementation of homotopy reduction

Author: slavapestov

lib/AST/CMakeLists.txt

@@ -74,6 +74,7 @@ add_swift_host_library(swiftAST STATIC
   ProtocolConformance.cpp
   RawComment.cpp
   RequirementEnvironment.cpp
+  RequirementMachine/HomotopyReduction.cpp
   RequirementMachine/GenericSignatureQueries.cpp
   RequirementMachine/PropertyMap.cpp
   RequirementMachine/ProtocolGraph.cpp

lib/AST/RequirementMachine/Debug.h

@@ -34,10 +34,10 @@ enum class DebugFlags : unsigned {
   ConcreteUnification = (1<<4),
 
   /// Print debug output when concretizing nested types in the property map.
-  ConcretizeNestedTypes = (1<<5)
+  ConcretizeNestedTypes = (1<<5),
 
   /// Print debug output from the homotopy reduction algorithm.
-  HomotopyReduction = (1<<7),
+  HomotopyReduction = (1<<6)
 };
 
 using DebugOptions = OptionSet<DebugFlags>;