RequirementMachine: Turn off redundant requirement warnings by default and add -warn-redundant-requirements frontend flag

Author: slavapestov

include/swift/Basic/LangOptions.h

@@ -572,6 +572,9 @@ 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/RequirementMachine/Diagnostics.cpp

@@ -138,6 +138,11 @@ bool swift::rewriting::diagnoseRequirementErrors(
     }
 
     case RequirementError::Kind::RedundantRequirement: {
+      // We only emit redundant requirement warnings if the user passed
+      // the -warn-redundant-requirements frontend flag.
+      if (!ctx.LangOpts.WarnRedundantRequirements)
+        break;
+
       auto requirement = error.requirement;
       if (requirement.hasError())
         break;

lib/Frontend/CompilerInvocation.cpp

@@ -1057,6 +1057,9 @@ static bool ParseLangArgs(LangOptions &Opts, ArgList &Args,
   if (Args.hasArg(OPT_enable_requirement_machine_opaque_archetypes))
     Opts.EnableRequirementMachineOpaqueArchetypes = true;
 
+  if (Args.hasArg(OPT_warn_redundant_requirements))
+    Opts.WarnRedundantRequirements = true;
+
   Opts.DumpTypeWitnessSystems = Args.hasArg(OPT_dump_type_witness_systems);
 
   return HadError || UnsupportedOS || UnsupportedArch;

test/AutoDiff/SILGen/differentiability_witness_generic_signature.swift

@@ -1,5 +1,5 @@
-// RUN: %target-swift-emit-silgen -verify -module-name main %s -requirement-machine-inferred-signatures=on | %FileCheck %s
-// RUN: %target-swift-emit-sil -verify -module-name main %s -requirement-machine-inferred-signatures=on
+// RUN: %target-swift-emit-silgen -verify -module-name main %s -requirement-machine-inferred-signatures=on -warn-redundant-requirements | %FileCheck %s
+// RUN: %target-swift-emit-sil -verify -module-name main %s -requirement-machine-inferred-signatures=on -warn-redundant-requirements
 
 // NOTE(SR-11950): SILParser crashes for SILGen round-trip.
 

test/AutoDiff/SILOptimizer/generics.swift

@@ -1,4 +1,4 @@
-// RUN: %target-swift-emit-sil -verify %s -requirement-machine-inferred-signatures=on | %FileCheck %s -check-prefix=CHECK-SIL
+// RUN: %target-swift-emit-sil -verify %s -requirement-machine-inferred-signatures=on -warn-redundant-requirements | %FileCheck %s -check-prefix=CHECK-SIL
 
 import _Differentiation
 

test/Compatibility/anyobject_class.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -swift-version 4 -requirement-machine-protocol-signatures=on
+// RUN: %target-typecheck-verify-swift -swift-version 4 -requirement-machine-protocol-signatures=on -warn-redundant-requirements
 // RUN: not %target-swift-frontend -typecheck -swift-version 5 -requirement-machine-protocol-signatures=on
 
 protocol P : class, AnyObject { } // expected-warning{{redundant inheritance from 'AnyObject' and Swift 3 'class' keyword}}{{14-21=}}

test/Constraints/generic_super_constraint.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift %s -requirement-machine-inferred-signatures=on
+// RUN: %target-typecheck-verify-swift %s -requirement-machine-inferred-signatures=on -warn-redundant-requirements
 
 class Base<T> { }
 class Derived: Base<Int> { }

test/Constraints/same_types.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -requirement-machine-inferred-signatures=on
+// RUN: %target-typecheck-verify-swift -requirement-machine-inferred-signatures=on -warn-redundant-requirements
 // RUN: not %target-swift-frontend -typecheck %s -debug-generic-signatures -requirement-machine-inferred-signatures=on 2>&1 | %FileCheck %s
 
 protocol Fooable {

test/Generics/associated_type_typo.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -requirement-machine-protocol-signatures=on -requirement-machine-inferred-signatures=on
+// RUN: %target-typecheck-verify-swift -requirement-machine-protocol-signatures=on -requirement-machine-inferred-signatures=on -warn-redundant-requirements
 
 // RUN: not %target-swift-frontend -typecheck -debug-generic-signatures %s -requirement-machine-protocol-signatures=on -requirement-machine-inferred-signatures=on > %t.dump 2>&1 
 // RUN: %FileCheck -check-prefix CHECK-GENERIC %s < %t.dump

test/Generics/associated_type_where_clause.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -swift-version 4 -requirement-machine-protocol-signatures=on
+// RUN: %target-typecheck-verify-swift -swift-version 4 -requirement-machine-protocol-signatures=on -warn-redundant-requirements
 
 func needsSameType<T>(_: T.Type, _: T.Type) {}
 

test/Generics/canonicalization.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -requirement-machine-inferred-signatures=on
+// RUN: %target-typecheck-verify-swift -requirement-machine-inferred-signatures=on -warn-redundant-requirements
 
 // rdar://problem/23149063
 protocol P0 { }

test/Generics/concrete_conformances_in_protocol.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -warn-redundant-requirements
 // RUN: %target-swift-frontend -typecheck %s -debug-generic-signatures 2>&1 | %FileCheck %s
 
 protocol P {

test/Generics/concrete_contraction_unrelated_typealias.swift

@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -typecheck -verify %s -debug-generic-signatures -requirement-machine-inferred-signatures=on 2>&1 | %FileCheck %s
+// RUN: %target-swift-frontend -typecheck -verify %s -debug-generic-signatures -requirement-machine-inferred-signatures=on -warn-redundant-requirements 2>&1 | %FileCheck %s
 
 // Another GenericSignatureBuilder oddity, reduced from RxSwift.
 //

test/Generics/concrete_same_type_versus_anyobject.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -requirement-machine-inferred-signatures=on
+// RUN: %target-typecheck-verify-swift -requirement-machine-inferred-signatures=on -warn-redundant-requirements
 // RUN: not %target-swift-frontend -typecheck -debug-generic-signatures -requirement-machine-inferred-signatures=on %s 2>&1 | %FileCheck %s
 
 struct S {}

test/Generics/conditional_conformances.swift

@@ -1,5 +1,5 @@
-// RUN: %target-typecheck-verify-swift -requirement-machine-inferred-signatures=on
-// RUN: %target-typecheck-verify-swift -debug-generic-signatures -requirement-machine-inferred-signatures=on > %t.dump 2>&1
+// RUN: %target-typecheck-verify-swift -requirement-machine-inferred-signatures=on -warn-redundant-requirements
+// RUN: %target-typecheck-verify-swift -debug-generic-signatures -requirement-machine-inferred-signatures=on -warn-redundant-requirements > %t.dump 2>&1
 // RUN: %FileCheck %s < %t.dump
 
 protocol P1 {}

test/Generics/conditional_requirement_inference_in_protocol.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -requirement-machine-protocol-signatures=on -requirement-machine-inferred-signatures=on
+// RUN: %target-typecheck-verify-swift -requirement-machine-protocol-signatures=on -requirement-machine-inferred-signatures=on -warn-redundant-requirements
 // RUN: %target-swift-frontend -typecheck %s -debug-generic-signatures -requirement-machine-protocol-signatures=on -requirement-machine-inferred-signatures=on 2>&1 | %FileCheck %s
 
 // FIXME(rqm-diagnostics): The redundant conformance warnings here should not be emitted, since

test/Generics/conformance_access_path.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -swift-version 4 -requirement-machine-protocol-signatures=on
+// RUN: %target-typecheck-verify-swift -swift-version 4 -requirement-machine-protocol-signatures=on -warn-redundant-requirements
 
 protocol P0 { }
 protocol Q0: P0 { }

test/Generics/derived_via_concrete.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -requirement-machine-inferred-signatures=on
+// RUN: %target-typecheck-verify-swift -requirement-machine-inferred-signatures=on -warn-redundant-requirements
 // RUN: %target-swift-frontend -typecheck %s -debug-generic-signatures -requirement-machine-inferred-signatures=on 2>&1 | %FileCheck %s
 
 protocol P {}

test/Generics/derived_via_concrete_in_protocol.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -requirement-machine-protocol-signatures=on
+// RUN: %target-typecheck-verify-swift -requirement-machine-protocol-signatures=on -warn-redundant-requirements
 // RUN: %target-swift-frontend -debug-generic-signatures -typecheck %s -requirement-machine-protocol-signatures=on 2>&1 | %FileCheck %s
 
 protocol P24 {
@@ -52,4 +52,4 @@ protocol P27a {
 protocol P27b {
   associatedtype A
   associatedtype B: X3 where A == X26<B>
-}
+}

test/Generics/function_defs.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -warn-redundant-requirements
 
 //===----------------------------------------------------------------------===//
 // Type-check function definitions

test/Generics/interdependent_protocol_conformance_example_1.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift %s -requirement-machine-protocol-signatures=on
+// RUN: %target-typecheck-verify-swift %s -requirement-machine-protocol-signatures=on -warn-redundant-requirements
 // RUN: %target-swift-frontend -typecheck %s -debug-generic-signatures -requirement-machine-protocol-signatures=on 2>&1 | %FileCheck %s
 
 // The GenericSignatureBuilder was unable to derive the redundant conformance requirement 'B: P4'

test/Generics/interdependent_protocol_conformance_example_3.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -requirement-machine-protocol-signatures=on -requirement-machine-inferred-signatures=on
+// RUN: %target-typecheck-verify-swift -requirement-machine-protocol-signatures=on -requirement-machine-inferred-signatures=on -warn-redundant-requirements
 // RUN: %target-swift-frontend -typecheck %s -debug-generic-signatures -requirement-machine-protocol-signatures=on -requirement-machine-inferred-signatures=on 2>&1 | %FileCheck %s
 // RUN: %target-swift-frontend -typecheck %s -debug-generic-signatures -disable-requirement-machine-reuse -requirement-machine-protocol-signatures=on -requirement-machine-inferred-signatures=on 2>&1 | %FileCheck %s
 

test/Generics/interdependent_protocol_conformance_example_5.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -requirement-machine-protocol-signatures=on -requirement-machine-inferred-signatures=on
+// RUN: %target-typecheck-verify-swift -requirement-machine-protocol-signatures=on -requirement-machine-inferred-signatures=on -warn-redundant-requirements
 // RUN: %target-swift-frontend -typecheck %s -debug-generic-signatures -requirement-machine-protocol-signatures=on -requirement-machine-inferred-signatures=on 2>&1 | %FileCheck %s
 // RUN: %target-swift-frontend -typecheck %s -debug-generic-signatures -disable-requirement-machine-reuse -requirement-machine-protocol-signatures=on -requirement-machine-inferred-signatures=on 2>&1 | %FileCheck %s
 

test/Generics/non_final_class_conforms_same_type_requirement_on_self.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -requirement-machine-inferred-signatures=on
+// RUN: %target-typecheck-verify-swift -requirement-machine-inferred-signatures=on -warn-redundant-requirements
 // RUN: %target-swift-frontend -typecheck -debug-generic-signatures -requirement-machine-inferred-signatures=on %s 2>&1 | %FileCheck %s
 // RUN: %target-swift-frontend -typecheck -debug-generic-signatures -requirement-machine-inferred-signatures=on -disable-requirement-machine-concrete-contraction %s 2>&1 | %FileCheck %s
 
@@ -75,4 +75,4 @@ public class SuperclassExampleC : SuperclassExampleP {
 
 public class SuperclassExampleD : Q {
   public typealias B = G<SuperclassExampleC>
-}
+}

test/Generics/protocol_requirement_signatures.swift

@@ -1,5 +1,5 @@
-// RUN: %target-typecheck-verify-swift -requirement-machine-protocol-signatures=on
-// RUN: %target-typecheck-verify-swift -debug-generic-signatures -requirement-machine-protocol-signatures=on > %t.dump 2>&1
+// RUN: %target-typecheck-verify-swift -requirement-machine-protocol-signatures=on -warn-redundant-requirements
+// RUN: %target-typecheck-verify-swift -debug-generic-signatures -requirement-machine-protocol-signatures=on -warn-redundant-requirements > %t.dump 2>&1
 // RUN: %FileCheck %s < %t.dump
 
 // CHECK-LABEL: .P1@

test/Generics/protocol_type_aliases.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -requirement-machine-protocol-signatures=on -requirement-machine-inferred-signatures=on
+// RUN: %target-typecheck-verify-swift -requirement-machine-protocol-signatures=on -requirement-machine-inferred-signatures=on -warn-redundant-requirements
 // RUN: not %target-swift-frontend -typecheck %s -debug-generic-signatures -requirement-machine-protocol-signatures=on -requirement-machine-inferred-signatures=on > %t.dump 2>&1
 
 

test/Generics/protocol_typealias_cycle_5.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -requirement-machine-protocol-signatures=on
+// RUN: %target-typecheck-verify-swift -requirement-machine-protocol-signatures=on -warn-redundant-requirements
 
 protocol P : Sequence {
   typealias Element = Iterator.Element

test/Generics/rdar51908331.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -requirement-machine-protocol-signatures=on -requirement-machine-inferred-signatures=on -requirement-machine-abstract-signatures=on
+// RUN: %target-typecheck-verify-swift -requirement-machine-protocol-signatures=on -requirement-machine-inferred-signatures=on -requirement-machine-abstract-signatures=on -warn-redundant-requirements
 
 // Reduced from https://github.com/plx/HDXLSIMDSupport.
 

test/Generics/rdar62903491.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -requirement-machine-inferred-signatures=on
+// RUN: %target-typecheck-verify-swift -requirement-machine-inferred-signatures=on -warn-redundant-requirements
 // RUN: %target-swift-frontend -typecheck -debug-generic-signatures %s -requirement-machine-inferred-signatures=on 2>&1 | %FileCheck %s
 
 protocol P {

test/Generics/rdar65263302.swift

@@ -1,5 +1,5 @@
-// RUN: %target-swift-frontend -typecheck -debug-generic-signatures %s -requirement-machine-inferred-signatures=on 2>&1 | %FileCheck %s
-// RUN: %target-swift-frontend -verify -emit-ir %s -requirement-machine-inferred-signatures=on
+// RUN: %target-swift-frontend -typecheck -debug-generic-signatures %s -requirement-machine-inferred-signatures=on -warn-redundant-requirements 2>&1 | %FileCheck %s
+// RUN: %target-swift-frontend -verify -emit-ir %s -requirement-machine-inferred-signatures=on -warn-redundant-requirements
 
 public protocol P {
     associatedtype Element

test/Generics/rdar74890907.swift

@@ -1,5 +1,5 @@
-// RUN: %target-typecheck-verify-swift -requirement-machine-inferred-signatures=on
-// RUN: %target-swift-frontend -typecheck -debug-generic-signatures %s -requirement-machine-inferred-signatures=on 2>&1 | %FileCheck %s
+// RUN: %target-typecheck-verify-swift -requirement-machine-inferred-signatures=on -warn-redundant-requirements
+// RUN: %target-swift-frontend -typecheck -debug-generic-signatures %s -requirement-machine-inferred-signatures=on -warn-redundant-requirements 2>&1 | %FileCheck %s
 
 protocol P1 {
   associatedtype A : P2

test/Generics/rdar75656022.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -requirement-machine-protocol-signatures=on -requirement-machine-inferred-signatures=on
+// RUN: %target-typecheck-verify-swift -requirement-machine-protocol-signatures=on -requirement-machine-inferred-signatures=on -warn-redundant-requirements
 // RUN: %target-swift-frontend -typecheck -debug-generic-signatures %s -requirement-machine-protocol-signatures=on -requirement-machine-inferred-signatures=on 2>&1 | %FileCheck %s
 
 protocol P1 {

test/Generics/rdar77462797.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -requirement-machine-inferred-signatures=on
+// RUN: %target-typecheck-verify-swift -requirement-machine-inferred-signatures=on -warn-redundant-requirements
 // RUN: %target-swift-frontend -typecheck %s -debug-generic-signatures -requirement-machine-inferred-signatures=on 2>&1 | %FileCheck %s
 
 protocol P {}
@@ -32,4 +32,4 @@ struct G<X, Y> where X : Q {
 
 func foo<X, Y>(_: X, _: Y) where X : Q, X : S<Y>, Y : P {}
 // expected-warning@-1 {{redundant conformance constraint 'S<Y>' : 'Q'}}
-// CHECK: Generic signature: <X, Y where X : S<Y>, Y : P>
+// CHECK: Generic signature: <X, Y where X : S<Y>, Y : P>

test/Generics/rdar83308672.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -debug-generic-signatures -requirement-machine-protocol-signatures=on 2>&1 | %FileCheck %s
+// RUN: %target-typecheck-verify-swift -debug-generic-signatures -requirement-machine-protocol-signatures=on -warn-redundant-requirements 2>&1 | %FileCheck %s
 
 // CHECK: rdar83308672.(file).A@
 // CHECK-NEXT: Requirement signature: <Self where Self == Self.[A]X.[P1]T, Self.[A]X : P1, Self.[A]Y : P2>

test/Generics/rdar83687967.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -requirement-machine-protocol-signatures=on -requirement-machine-inferred-signatures=on
+// RUN: %target-typecheck-verify-swift -requirement-machine-protocol-signatures=on -requirement-machine-inferred-signatures=on -warn-redundant-requirements
 // RUN: %target-swift-frontend -typecheck -debug-generic-signatures %s -requirement-machine-protocol-signatures=on -requirement-machine-inferred-signatures=on 2>&1 | %FileCheck %s
 // RUN: %target-swift-frontend -emit-ir %s
 

test/Generics/rdar91771352.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -warn-redundant-requirements
 // RUN: %target-swift-frontend -typecheck %s -debug-generic-signatures 2>&1 | %FileCheck %s
 
 public struct G<T: P1, U: P1> {

test/Generics/redundant_concrete_conformance.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -requirement-machine-protocol-signatures=on -requirement-machine-inferred-signatures=on
+// RUN: %target-typecheck-verify-swift -requirement-machine-protocol-signatures=on -requirement-machine-inferred-signatures=on -warn-redundant-requirements
 
 protocol P1 {}
 protocol P2 : P1 {}
@@ -13,4 +13,4 @@ func f1<T : P3>(_: T) where T.A : P1 {}
 // expected-warning@-1 {{redundant conformance constraint 'T.A' : 'P1'}}
 
 func f2<T : P3>(_: T) where T.A : P2 {}
-// expected-warning@-1 {{redundant conformance constraint 'T.A' : 'P2'}}
+// expected-warning@-1 {{redundant conformance constraint 'T.A' : 'P2'}}

test/Generics/redundant_inferred_requirement_order.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -warn-redundant-requirements
 
 protocol P {}
 
@@ -11,4 +11,4 @@ extension G where A == S<B>, B : P {}
 extension G where B : P, A == S<B> {}
 
 extension G where B : P, A == S<B>, B : P {}
-// expected-warning@-1 {{redundant conformance constraint 'B' : 'P'}}
+// expected-warning@-1 {{redundant conformance constraint 'B' : 'P'}}

test/Generics/redundant_protocol_composition.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -requirement-machine-inferred-signatures=on
+// RUN: %target-typecheck-verify-swift -requirement-machine-inferred-signatures=on -warn-redundant-requirements
 
 // The GenericSignatureBuilder did not diagnose the first two.
 

test/Generics/redundant_protocol_refinement.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -requirement-machine-protocol-signatures=on
+// RUN: %target-typecheck-verify-swift -requirement-machine-protocol-signatures=on -warn-redundant-requirements
 // RUN: %target-swift-frontend -typecheck -debug-generic-signatures -requirement-machine-protocol-signatures=on %s 2>&1 | %FileCheck %s
 
 // CHECK-LABEL: redundant_protocol_refinement.(file).Base@

test/Generics/redundant_requirement_self_conforming_protocol.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -requirement-machine-inferred-signatures=on
+// RUN: %target-typecheck-verify-swift -requirement-machine-inferred-signatures=on -warn-redundant-requirements
 // RUN: %target-swift-frontend -typecheck -debug-generic-signatures %s -requirement-machine-inferred-signatures=on 2>&1 | %FileCheck %s
 
 struct G<T> {}

test/Generics/requirement_inference.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -requirement-machine-protocol-signatures=on -requirement-machine-inferred-signatures=on
+// RUN: %target-typecheck-verify-swift -requirement-machine-protocol-signatures=on -requirement-machine-inferred-signatures=on -warn-redundant-requirements
 // RUN: not %target-swift-frontend -typecheck %s -debug-generic-signatures -requirement-machine-protocol-signatures=on -requirement-machine-inferred-signatures=on 2>&1 | %FileCheck %s
 
 protocol P1 { 

test/Generics/requirement_machine_diagnostics.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -requirement-machine-protocol-signatures=on -requirement-machine-inferred-signatures=on
+// RUN: %target-typecheck-verify-swift -requirement-machine-protocol-signatures=on -requirement-machine-inferred-signatures=on -warn-redundant-requirements
 
 func testInvalidConformance() {
   // expected-error@+1 {{type 'T' constrained to non-protocol, non-class type 'Int'}}

test/Generics/same_type_constraints.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -swift-version 4 -requirement-machine-protocol-signatures=on -requirement-machine-inferred-signatures=on
+// RUN: %target-typecheck-verify-swift -swift-version 4 -requirement-machine-protocol-signatures=on -requirement-machine-inferred-signatures=on -warn-redundant-requirements
 
 protocol Fooable {
   associatedtype Foo