[SIL] Allow init accessor declarations in constrained extensions

While emitting a function type for init accessor reference
"self" parameter should always be mapped into the context.

When referencing an init accessor in an constrained extension
context, substitution map for the original property cannot
always be used when applying "self" parameter, emission logic
eeds to check whether context makes the init accessor reference
"concrete" and if so, avoid using the substitution map
when forming partial application for "self" parameter.

Resolves: rdar://160816474

Author: xedin

lib/SIL/IR/SILFunctionType.cpp

@@ -2955,8 +2955,10 @@ static CanSILFunctionType getSILFunctionTypeForInitAccessor(
 
   // Make a new 'self' parameter.
   if (!declContext->isLocalContext()) {
-    auto selfInterfaceType =
-        MetatypeType::get(declContext->getSelfInterfaceType());
+    auto selfInterfaceType = MetatypeType::get(
+        (genericSig)
+            ? declContext->getSelfInterfaceType()->getReducedType(genericSig)
+            : declContext->getSelfTypeInContext());
     AbstractionPattern origSelfType(genericSig,
                                     selfInterfaceType->getCanonicalType());
     auto loweredSelfType = TC.getLoweredType(

lib/SILGen/SILGenFunction.cpp

@@ -1931,11 +1931,6 @@ void SILGenFunction::emitAssignOrInit(SILLocation loc, ManagedValue selfValue,
 
   auto initTy = initFRef->getType().castTo<SILFunctionType>();
 
-  // If there are substitutions we need to emit partial apply to
-  // apply substitutions to the init accessor reference type.
-  initTy = initTy->substGenericArgs(SGM.M, substitutions,
-                                    getTypeExpansionContext());
-
   // Emit partial apply with self metatype argument to produce a substituted
   // init accessor reference.
   auto selfTy = selfValue.getType().getASTType();
@@ -1949,8 +1944,9 @@ void SILGenFunction::emitAssignOrInit(SILLocation loc, ManagedValue selfValue,
     selfMetatype = B.createMetatype(loc, getLoweredType(metatypeTy));
   }
 
-  auto expectedSelfTy = initAccessor->getDeclContext()->getSelfInterfaceType()
-      .subst(substitutions);
+  auto expectedSelfTy =
+      initAccessor->getDeclContext()->getSelfInterfaceType().subst(
+          substitutions);
 
   // This should only happen in the invalid case where we attempt to initialize
   // superclass storage from a subclass initializer. However, we shouldn't
@@ -1960,6 +1956,14 @@ void SILGenFunction::emitAssignOrInit(SILLocation loc, ManagedValue selfValue,
     selfMetatype = B.createUpcast(loc, selfMetatype,
                              getLoweredType(MetatypeType::get(expectedSelfTy)));
   }
+
+  if (auto invocationSig = initTy->getInvocationGenericSignature()) {
+    if (invocationSig->areAllParamsConcrete())
+      substitutions = SubstitutionMap();
+  } else {
+    substitutions = SubstitutionMap();
+  }
+
   PartialApplyInst *initPAI =
       B.createPartialApply(loc, initFRef, substitutions, selfMetatype,
                            ParameterConvention::Direct_Guaranteed,

test/SILOptimizer/init_accessor_in_constrained_extensions.swift

@@ -0,0 +1,73 @@
+// RUN: %target-swift-frontend -Xllvm -sil-print-types -Xllvm -sil-print-after=definite-init -emit-sil -module-name assign_or_init_lowering %s -o /dev/null 2>&1 | %FileCheck %s
+
+struct S1<T> {
+}
+
+extension S1 where T == Int {
+  class Test {
+    var test1: Int {
+      init(initialValue) { }
+      set {}
+      get { 0 }
+    }
+
+    var test2: T {
+      init(initialValue) { }
+      set {}
+      get { 0 }
+    }
+
+    // CHECK-LABEL: sil hidden [ossa] @$s23assign_or_init_lowering2S1VAASiRszlE4TestCAEySi_Gycfc : $@convention(method) (@owned S1<Int>.Test) -> @owned S1<Int>.Test
+    //
+    // CHECK: [[TEST1_INIT_REF:%.*]] = function_ref @$s23assign_or_init_lowering2S1VAASiRszlE4TestC5test1Sivi : $@convention(thin) (Int, @thick S1<Int>.Test.Type) -> ()
+    // CHECK-NEXT: [[SELF:%.*]] = value_metatype $@thick S1<Int>.Test.Type, {{.*}} : $S1<Int>.Test
+    // CHECK-NEXT: [[TEST1_INIT_REF_WITH_SELF_APPLIED:%.*]] = partial_apply [callee_guaranteed] [on_stack] [[TEST1_INIT_REF]]([[SELF]]) : $@convention(thin) (Int, @thick S1<Int>.Test.Type) -> ()
+    // CHECK: assign_or_init [init] #S1.Test.test1, self {{.*}} : $S1<Int>.Test, value {{.*}} : $Int, init [[TEST1_INIT_REF_WITH_SELF_APPLIED]] : $@noescape @callee_guaranteed (Int) -> (), set {{.*}} : $@noescape @callee_guaranteed (Int) -> ()
+    //
+    // CHECK: [[TEST2_INIT_REF:%.*]] = function_ref @$s23assign_or_init_lowering2S1VAASiRszlE4TestC5test2Sivi : $@convention(thin) (Int, @thick S1<Int>.Test.Type) -> ()
+    // CHECK-NEXT: [[SELF:%.*]] = value_metatype $@thick S1<Int>.Test.Type, {{.*}} : $S1<Int>.Test
+    // CHECK-NEXT: [[TEST2_INIT_REF_WITH_SELF_APPLIED:%.*]] = partial_apply [callee_guaranteed] [on_stack] [[TEST2_INIT_REF]]([[SELF]]) : $@convention(thin) (Int, @thick S1<Int>.Test.Type) -> ()
+    // CHECK: assign_or_init [init] #S1.Test.test2, self {{.*}} : $S1<Int>.Test, value {{.*}} : $Int, init [[TEST2_INIT_REF_WITH_SELF_APPLIED]] : $@noescape @callee_guaranteed (Int) -> (), set {{.*}} : $@noescape @callee_guaranteed (Int) -> ()
+    // CHECK: } // end sil function '$s23assign_or_init_lowering2S1VAASiRszlE4TestCAEySi_Gycfc'
+    init() {
+      test1 = 0
+      test2 = 1
+    }
+  }
+}
+
+struct S2<T, U> {
+}
+
+extension S2 where T == Int {
+  class Test {
+    var test1: T {
+      init(initialValue) { }
+      set {}
+      get { 0 }
+    }
+
+    var test2: U {
+      init(initialValue) { }
+      set {}
+      get { fatalError() }
+    }
+
+    // CHECK-LABEL: sil hidden [ossa] @$s23assign_or_init_lowering2S2VAASiRszrlE4TestC1uAEySiq__Gq__tcfc : $@convention(method) <T, U where T == Int> (@in U, @owned S2<Int, U>.Test) -> @owned S2<Int, U>.Test {
+    //
+    // CHECK: [[TEST1_INIT_REF:%.*]] = function_ref @$s23assign_or_init_lowering2S2VAASiRszrlE4TestC5test1Sivi : $@convention(thin) <τ_0_0, τ_0_1 where τ_0_0 == Int> (Int, @thick S2<Int, τ_0_1>.Test.Type) -> ()
+    // CHECK-NEXT: [[SELF:%.*]] = value_metatype $@thick S2<Int, U>.Test.Type, {{.*}} : $S2<Int, U>.Test
+    // CHECK-NEXT: [[TEST1_INIT_REF_WITH_SELF_APPLIED:%.*]] = partial_apply [callee_guaranteed] [on_stack] [[TEST1_INIT_REF]]<Int, U>([[SELF]]) : $@convention(thin) <τ_0_0, τ_0_1 where τ_0_0 == Int> (Int, @thick S2<Int, τ_0_1>.Test.Type) -> ()
+    // CHECK: assign_or_init [init] #S2.Test.test1, self {{.*}} : $S2<Int, U>.Test, value {{.*}} : $Int, init [[TEST1_INIT_REF_WITH_SELF_APPLIED]] : $@noescape @callee_guaranteed (Int) -> (), set {{.*}} : $@noescape @callee_guaranteed (Int) -> ()
+    //
+    // CHECK: [[TEST2_INIT_REF:%.*]] = function_ref @$s23assign_or_init_lowering2S2VAASiRszrlE4TestC5test2q_vi : $@convention(thin) <τ_0_0, τ_0_1 where τ_0_0 == Int> (@in τ_0_1, @thick S2<Int, τ_0_1>.Test.Type) -> ()
+    // CHECK-NEXT: [[SELF:%.*]] = value_metatype $@thick S2<Int, U>.Test.Type, {{.*}} : $S2<Int, U>.Test
+    // CHECK-NEXT: [[TEST2_INIT_REF_WITH_SELF_APPLIED:%.*]] = partial_apply [callee_guaranteed] [on_stack] [[TEST2_INIT_REF]]<Int, U>([[SELF]]) : $@convention(thin) <τ_0_0, τ_0_1 where τ_0_0 == Int> (@in τ_0_1, @thick S2<Int, τ_0_1>.Test.Type) -> ()
+    // CHECK: assign_or_init [init] #S2.Test.test2, self {{.*}} : $S2<Int, U>.Test, value {{.*}} : $*U, init [[TEST2_INIT_REF_WITH_SELF_APPLIED]] : $@noescape @callee_guaranteed (@in U) -> (), set {{.*}} : $@noescape @callee_guaranteed (@in U) -> ()
+    // CHECK: } // end sil function '$s23assign_or_init_lowering2S2VAASiRszrlE4TestC1uAEySiq__Gq__tcfc'
+    init(u: U) {
+      test1 = 0
+      test2 = u
+    }
+  }
+}