Merge pull request swiftlang#58814 from slavapestov/rqm-tweak-diagnostics-5.7

[5.7] RequirementMachine: Disable redundant requirement diagnostics by default

Author: slavapestov

include/swift/Basic/LangOptions.h

@@ -569,6 +569,9 @@ namespace swift {
     /// rewrite system.
     bool EnableRequirementMachineOpaqueArchetypes = false;
 
+    /// Enable warnings for redundant requirements in generic signatures.
+    bool WarnRedundantRequirements = false;
+
     /// Enables dumping type witness systems from associated type inference.
     bool DumpTypeWitnessSystems = false;
 

include/swift/Option/FrontendOptions.td

@@ -378,6 +378,9 @@ def disable_requirement_machine_reuse : Flag<["-"], "disable-requirement-machine
 def enable_requirement_machine_opaque_archetypes : Flag<["-"], "enable-requirement-machine-opaque-archetypes">,
   HelpText<"Enable more correct opaque archetype support, which is off by default because it might fail to produce a convergent rewrite system">;
 
+def warn_redundant_requirements : Flag<["-"], "warn-redundant-requirements">,
+  HelpText<"Emit warnings for redundant requirements in generic signatures">;
+
 def dump_type_witness_systems : Flag<["-"], "dump-type-witness-systems">,
   HelpText<"Enables dumping type witness systems from associated type inference">;
 

lib/AST/CMakeLists.txt

@@ -79,6 +79,7 @@ add_swift_host_library(swiftAST STATIC
   RequirementEnvironment.cpp
   RequirementMachine/ConcreteContraction.cpp
   RequirementMachine/ConcreteTypeWitness.cpp
+  RequirementMachine/Diagnostics.cpp
   RequirementMachine/GenericSignatureQueries.cpp
   RequirementMachine/HomotopyReduction.cpp
   RequirementMachine/InterfaceType.cpp