Merge pull request #39869 from slavapestov/another-rqm-testcase

RequirementMachine: Add another requirement signature minimization test case

Author: slavapestov

test/Generics/confluent_example.swift

@@ -0,0 +1,27 @@
+// RUN: %target-swift-frontend -typecheck %s -debug-generic-signatures -requirement-machine-protocol-signatures=on 2>&1 | %FileCheck %s
+
+// The GSB crashes with P1 and P2, and rejects P3.
+
+// CHECK-LABEL: confluent_example.(file).P1@
+// CHECK-LABEL: Requirement signature: <Self where Self.A : P1, Self.A == Self.A.B, Self.B : P1, Self.B == Self.B.C, Self.C : P1>
+protocol P1 {
+  associatedtype A : P1
+  associatedtype B : P1
+  associatedtype C : P1 where A.B == A, B.C == B
+}
+
+// CHECK-LABEL: confluent_example.(file).P2@
+// CHECK-LABEL: Requirement signature: <Self where Self.A : P2, Self.A == Self.A.B, Self.B : P2, Self.B == Self.B.C, Self.C : P2>
+protocol P2 {
+  associatedtype A : P2
+  associatedtype B : P2
+  associatedtype C : P2 where A.B == A, B.C == B, A.C == A
+}
+
+// CHECK-LABEL: confluent_example.(file).P3@
+// CHECK-LABEL: Requirement signature: <Self where Self.A : P3, Self.A == Self.A.B, Self.B : P3, Self.B == Self.B.C, Self.C : P3>
+protocol P3 {
+  associatedtype A where A.B : P3
+  associatedtype B where B.C : P3
+  associatedtype C : P3 where A.B == A, B.C == B, A.C == A
+}