GSB: Teach 'derived via concrete' computation about superclass constraints [5.3]

lib/AST/GenericSignatureBuilder.cpp

@@ -837,6 +837,11 @@ const RequirementSource *RequirementSource::getMinimalConformanceSource(
 
       if (parentEquivClass->concreteType)
         derivedViaConcrete = true;
+      else if (parentEquivClass->superclass &&
+               builder.lookupConformance(parentType->getCanonicalType(),
+                                         parentEquivClass->superclass,
+                                         source->getProtocolDecl()))
+        derivedViaConcrete = true;
 
       // The parent potential archetype must conform to the protocol in which
       // this requirement resides. Add this constraint.

test/Generics/superclass_constraint_self_derived.swift

@@ -0,0 +1,25 @@
+// RUN: %target-typecheck-verify-swift
+
+protocol P {
+  associatedtype T : Q
+}
+
+protocol Q {
+  associatedtype T : R
+
+  var t: T { get }
+}
+
+protocol R {}
+
+func takesR<T : R>(_: T) {}
+
+class C<T : Q> : P {}
+
+struct Outer<T : P> {
+  struct Inner<U> where T : C<U> {
+    func doStuff(_ u: U) {
+      takesR(u.t)
+    }
+  }
+}

test/SILGen/class_conforms_with_default_implementation.swift

@@ -0,0 +1,48 @@
+// RUN: %target-swift-emit-silgen %s | %FileCheck %s
+
+protocol P {
+  associatedtype T : Q
+  func foo()
+}
+
+extension P {
+  func foo() {}
+}
+
+protocol Q {}
+
+class C<T : Q> : P {}
+
+protocol PP {
+  associatedtype T : QQ
+  func foo()
+}
+
+extension PP {
+  func foo() {}
+}
+
+class QQ {}
+
+class CC<T : QQ> : PP {}
+
+// CHECK-LABEL: sil private [transparent] [thunk] [ossa] @$s42class_conforms_with_default_implementation1CCyqd__GAA1PA2aEP3fooyyFTW : $@convention(witness_method: P) <τ_0_0><τ_1_0 where τ_0_0 : C<τ_1_0>, τ_1_0 : Q> (@in_guaranteed τ_0_0) -> () {
+// CHECK: [[WITNESS:%.*]] = function_ref @$s42class_conforms_with_default_implementation1PPAAE3fooyyF : $@convention(method) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0) -> ()
+// CHECK: apply [[WITNESS]]<τ_0_0>(%0) : $@convention(method) <τ_0_0 where τ_0_0 : P> (@in_guaranteed τ_0_0) -> ()
+// CHECK: return
+
+// CHECK-LABEL: sil private [transparent] [thunk] [ossa] @$s42class_conforms_with_default_implementation2CCCyqd__GAA2PPA2aEP3fooyyFTW : $@convention(witness_method: PP) <τ_0_0><τ_1_0 where τ_0_0 : CC<τ_1_0>, τ_1_0 : QQ> (@in_guaranteed τ_0_0) -> () {
+// CHECK: [[WITNESS:%.*]] = function_ref @$s42class_conforms_with_default_implementation2PPPAAE3fooyyF : $@convention(method) <τ_0_0 where τ_0_0 : PP> (@in_guaranteed τ_0_0) -> ()
+// CHECK: apply [[WITNESS]]<τ_0_0>(%0) : $@convention(method) <τ_0_0 where τ_0_0 : PP> (@in_guaranteed τ_0_0) -> ()
+// CHECK: return
+
+// CHECK-LABEL: sil_witness_table hidden <T where T : Q> C<T>: P module class_conforms_with_default_implementation {
+// CHECK-NEXT: associated_type_protocol (T: Q): dependent
+// CHECK-NEXT: associated_type T: T
+// CHECK-NEXT: method #P.foo: <Self where Self : P> (Self) -> () -> () : @$s42class_conforms_with_default_implementation1CCyqd__GAA1PA2aEP3fooyyFTW
+// CHECK-NEXT: }
+
+// CHECK-LABEL: sil_witness_table hidden <T where T : QQ> CC<T>: PP module class_conforms_with_default_implementation {
+// CHECK-NEXT: associated_type T: T
+// CHECK-NEXT: method #PP.foo: <Self where Self : PP> (Self) -> () -> () : @$s42class_conforms_with_default_implementation2CCCyqd__GAA2PPA2aEP3fooyyFTW
+// CHECK-NEXT: }

validation-test/compiler_crashers_2/sr11108.swift → validation-test/compiler_crashers_2_fixed/sr11108.swift

@@ -1,6 +1,4 @@
-// RUN: not --crash %target-swift-emit-silgen %s
-
-// REQUIRES: asserts
+// RUN: %target-swift-emit-silgen %s
 
 protocol Example {
     associatedtype Signed: SignedInteger