SILGen: Fix keypath descriptor emission for class nested inside generic context

hasGenericParamList() is the wrong thing to check -- we actually need to
know if any parent context is generic, as well.

- Fixes #85860.

Author: slavapestov

lib/SILGen/SILGen.cpp

@@ -2080,7 +2080,7 @@ SILGenModule::canStorageUseStoredKeyPathComponent(AbstractStorageDecl *decl,
     // See the call to getClassFieldOffsetOffset() inside
     // emitKeyPathComponent().
     if (auto *parentClass = dyn_cast<ClassDecl>(decl->getDeclContext())) {
-      if (parentClass->hasGenericParamList()) {
+      if (parentClass->isGenericContext()) {
         auto ancestry = parentClass->checkAncestry();
         if (ancestry.contains(AncestryFlags::ResilientOther))
           return false;

test/SILGen/keypaths_resilient_generic.swift

@@ -8,6 +8,10 @@ import resilient_class
 
 open class MySubclass<T> : ResilientOutsideParent {
   public final var storedProperty: T? = nil
+
+  open class MyNestedClass : ResilientOutsideParent {
+    public final var storedProperty: T? = nil
+  }
 }
 
 open class ConcreteSubclass : MySubclass<Int> {
@@ -25,6 +29,13 @@ open class ConcreteSubclass : MySubclass<Int> {
 // CHECK-SAME:   setter @$s26keypaths_resilient_generic10MySubclassC14storedPropertyxSgvplACyxGTk : $@convention(keypath_accessor_setter) <τ_0_0> (@in_guaranteed Optional<τ_0_0>, @in_guaranteed MySubclass<τ_0_0>) -> ()
 // CHECK-SAME: )
 
+// CHECK:      sil_property #MySubclass.MyNestedClass.storedProperty<τ_0_0> (
+// CHECK-SAME:   settable_property $Optional<τ_0_0>,
+// CHECK-SAME:   id ##MySubclass.MyNestedClass.storedProperty,
+// CHECK-SAME:   getter @$s26keypaths_resilient_generic10MySubclassC0D11NestedClassC14storedPropertyxSgvplAEyx_GTK : $@convention(keypath_accessor_getter) <τ_0_0> (@in_guaranteed MySubclass<τ_0_0>.MyNestedClass) -> @out Optional<τ_0_0>,
+// CHECK-SAME:   setter @$s26keypaths_resilient_generic10MySubclassC0D11NestedClassC14storedPropertyxSgvplAEyx_GTk : $@convention(keypath_accessor_setter) <τ_0_0> (@in_guaranteed Optional<τ_0_0>, @in_guaranteed MySubclass<τ_0_0>.MyNestedClass) -> ()
+// CHECK-SAME: )
+
 // CHECK:      sil_property #ConcreteSubclass.anotherStoredProperty (
 // CHECK-SAME:   stored_property #ConcreteSubclass.anotherStoredProperty : $Optional<Int>
 // CHECK-SAME: )