Merge pull request #37620 from slavapestov/coroutine-witness-from-base-class

SIL: Use correct generic signature when computing yield types for witness thunks

Author: slavapestov

lib/SIL/IR/SILFunctionType.cpp

@@ -1988,6 +1988,7 @@ static void destructureYieldsForCoroutine(TypeConverter &TC,
                                           Optional<SILDeclRef> origConstant,
                                           Optional<SILDeclRef> constant,
                                           Optional<SubstitutionMap> reqtSubs,
+                                          Optional<GenericSignature> genericSig,
                                           SmallVectorImpl<SILYieldInfo> &yields,
                                           SILCoroutineKind &coroutineKind,
                                           SubstFunctionTypeCollector &subst) {
@@ -2012,12 +2013,14 @@ static void destructureYieldsForCoroutine(TypeConverter &TC,
 
   auto storage = accessor->getStorage();
   auto valueType = storage->getValueInterfaceType();
+
   if (reqtSubs) {
     valueType = valueType.subst(*reqtSubs);
   }
 
-  auto canValueType = valueType->getCanonicalType(
-    accessor->getGenericSignature());
+  auto canValueType = (genericSig
+                       ? valueType->getCanonicalType(*genericSig)
+                       : valueType->getCanonicalType());
 
   // 'modify' yields an inout of the target type.
   if (accessor->getAccessorKind() == AccessorKind::Modify) {
@@ -2178,7 +2181,8 @@ static CanSILFunctionType getSILFunctionType(
   SILCoroutineKind coroutineKind = SILCoroutineKind::None;
   SmallVector<SILYieldInfo, 8> yields;
   destructureYieldsForCoroutine(TC, expansionContext, origConstant, constant,
-                                reqtSubs, yields, coroutineKind, subst);
+                                reqtSubs, genericSig, yields, coroutineKind,
+                                subst);
 
   // Destructure the result tuple type.
   SmallVector<SILResultInfo, 8> results;

test/SILGen/witness-modify-requirement-with-base-class-modify.swift

@@ -0,0 +1,27 @@
+// RUN: %target-swift-emit-silgen %s | %FileCheck %s
+
+public protocol P {
+  associatedtype A
+}
+
+public class Base<T: P> {
+  public var foo: T.A?
+}
+
+public struct S {}
+
+public protocol Q {
+  var foo: S? {set get}
+}
+
+public class Derived<T: P> : Base<T>, Q where T.A == S {}
+
+// CHECK-LABEL: sil shared [transparent] [serialized] [thunk] [ossa] @$s4main7DerivedCyxGAA1QA2aEP3fooAA1SVSgvgTW : $@convention(witness_method: Q) <τ_0_0 where τ_0_0 : P, τ_0_0.A == S> (@in_guaranteed Derived<τ_0_0>) -> Optional<S> {
+// CHECK-LABEL: sil shared [transparent] [serialized] [thunk] [ossa] @$s4main7DerivedCyxGAA1QA2aEP3fooAA1SVSgvsTW : $@convention(witness_method: Q) <τ_0_0 where τ_0_0 : P, τ_0_0.A == S> (Optional<S>, @inout Derived<τ_0_0>) -> () {
+// CHECK-LABEL: sil shared [transparent] [serialized] [thunk] [ossa] @$s4main7DerivedCyxGAA1QA2aEP3fooAA1SVSgvMTW : $@yield_once @convention(witness_method: Q) <τ_0_0 where τ_0_0 : P, τ_0_0.A == S> @substituted <τ_0_0> (@inout τ_0_0) -> @yields @inout Optional<S> for <Derived<τ_0_0>> {
+
+// CHECK-LABEL: sil_witness_table [serialized] <T where T : P, T.A == S> Derived<T>: Q module main {
+// CHECK-NEXT:    method #Q.foo!getter: <Self where Self : Q> (Self) -> () -> S? : @$s4main7DerivedCyxGAA1QA2aEP3fooAA1SVSgvgTW
+// CHECK-NEXT:    method #Q.foo!setter: <Self where Self : Q> (inout Self) -> (S?) -> () : @$s4main7DerivedCyxGAA1QA2aEP3fooAA1SVSgvsTW
+// CHECK-NEXT:    method #Q.foo!modify: <Self where Self : Q> (inout Self) -> () -> () : @$s4main7DerivedCyxGAA1QA2aEP3fooAA1SVSgvMTW
+// CHECK-NEXT:  }