SILGen: Handle PackConformance in SILGenModule::useConformance()

Author: slavapestov

lib/SILGen/SILGenLazyConformance.cpp

@@ -12,7 +12,9 @@
 
 #include "SILGen.h"
 #include "swift/AST/Decl.h"
+#include "swift/AST/PackConformance.h"
 #include "swift/AST/ProtocolConformance.h"
+#include "swift/AST/ProtocolConformanceRef.h"
 #include "swift/ClangImporter/ClangModule.h"
 #include "swift/SIL/SILInstruction.h"
 #include "swift/SIL/SILVisitor.h"
@@ -31,6 +33,16 @@ void SILGenModule::useConformance(ProtocolConformanceRef conformanceRef) {
   if (conformanceRef.isAbstract())
     return;
 
+  // Recursively visit pack conformances.
+  if (conformanceRef.isPack()) {
+    auto *packConformance = conformanceRef.getPack();
+
+    for (auto patternConformanceRef : packConformance->getPatternConformances())
+      useConformance(patternConformanceRef);
+
+    return;
+  }
+
   auto conformance = conformanceRef.getConcrete();
 
   // Always look through inherited conformances.

test/SILGen/variadic_generic_types.swift

@@ -0,0 +1,8 @@
+// RUN: %target-swift-emit-silgen %s -enable-experimental-feature VariadicGenerics
+
+// Because of -enable-experimental-feature VariadicGenerics
+// REQUIRES: asserts
+
+struct Variadic<T...> where each T: Equatable {}
+
+_ = Variadic<Int, String>()