SIL: Support element archetypes inside lowerCaptureContextParameters()

Author: slavapestov

lib/SIL/IR/SILFunctionType.cpp

@@ -1934,11 +1934,7 @@ void updateResultTypeForForeignInfo(
   llvm_unreachable("unhandled kind");
 }
 
-/// Lower any/all capture context parameters.
-///
-/// *NOTE* Currently default arg generators can not capture anything.
-/// If we ever add that ability, it will be a different capture list
-/// from the function to which the argument is attached.
+/// Captured values become SIL function parameters in this function.
 static void
 lowerCaptureContextParameters(TypeConverter &TC, SILDeclRef function,
                               CanGenericSignature genericSig,
@@ -1962,28 +1958,38 @@ lowerCaptureContextParameters(TypeConverter &TC, SILDeclRef function,
   // signature from the AST for that.
   auto origGenericSig = function.getAnyFunctionRef()->getGenericSignature();
   auto loweredCaptures = TC.getLoweredLocalCaptures(function);
+  auto capturedEnvs = loweredCaptures.getGenericEnvironments();
   auto *isolatedParam = loweredCaptures.getIsolatedParamCapture();
 
+  auto mapTypeOutOfContext = [&](Type t) -> CanType {
+    LLVM_DEBUG(llvm::dbgs() << "-- capture with contextual type " << t << "\n");
+
+    t = t.subst(MapLocalArchetypesOutOfContext(origGenericSig, capturedEnvs),
+                MakeAbstractConformanceForGenericType(),
+                SubstFlags::PreservePackExpansionLevel);
+
+    LLVM_DEBUG(llvm::dbgs() << "-- maps to " << t->getCanonicalType() << "\n");
+    return t->getCanonicalType();
+  };
+
   for (auto capture : loweredCaptures.getCaptures()) {
     if (capture.isDynamicSelfMetadata()) {
       ParameterConvention convention = ParameterConvention::Direct_Unowned;
       auto dynamicSelfInterfaceType =
-          loweredCaptures.getDynamicSelfType()->mapTypeOutOfContext();
+          mapTypeOutOfContext(loweredCaptures.getDynamicSelfType());
 
-      auto selfMetatype = MetatypeType::get(dynamicSelfInterfaceType,
-                                            MetatypeRepresentation::Thick);
+      auto selfMetatype = CanMetatypeType::get(dynamicSelfInterfaceType,
+                                               MetatypeRepresentation::Thick);
 
-      auto canSelfMetatype = selfMetatype->getReducedType(origGenericSig);
-      SILParameterInfo param(canSelfMetatype, convention);
+      SILParameterInfo param(selfMetatype, convention);
       inputs.push_back(param);
 
       continue;
     }
 
     if (capture.isOpaqueValue()) {
       OpaqueValueExpr *opaqueValue = capture.getOpaqueValue();
-      auto canType = opaqueValue->getType()->mapTypeOutOfContext()
-          ->getReducedType(origGenericSig);
+      auto canType = mapTypeOutOfContext(opaqueValue->getType());
       auto &loweredTL =
           TC.getTypeLowering(AbstractionPattern(genericSig, canType),
                              canType, expansion);
@@ -2001,9 +2007,16 @@ lowerCaptureContextParameters(TypeConverter &TC, SILDeclRef function,
       continue;
     }
 
-    auto *varDecl = capture.getDecl();
-    auto type = varDecl->getInterfaceType();
-    auto canType = type->getReducedType(origGenericSig);
+    auto *varDecl = cast<VarDecl>(capture.getDecl());
+
+    auto type = varDecl->getTypeInContext();
+    assert(!type->hasLocalArchetype() ||
+           (genericSig && origGenericSig &&
+            !genericSig->isEqual(origGenericSig)));
+    type = mapTypeOutOfContext(type);
+
+    auto canType = type->getReducedType(
+        genericSig ? genericSig : origGenericSig);
 
     auto options = SILParameterInfo::Options();
     if (isolatedParam == varDecl) {