IRGen: Fix capture descriptor emission

Author: slavapestov

lib/IRGen/GenReflection.cpp

@@ -546,6 +546,10 @@ class CaptureDescriptorBuilder : public ReflectionMetadataBuilder {
     // the bindings structure directly.
     auto &Bindings = Layout.getBindings();
     for (unsigned i = 0; i < Bindings.size(); ++i) {
+      // Skip protocol requirements (FIXME: for now?)
+      if (Bindings[i].Protocol != nullptr)
+        continue;
+
       auto Source = SourceBuilder.createClosureBinding(i);
       auto BindingType = Caller.mapTypeOutOfContext(Bindings[i].TypeParameter);
       SourceMap.push_back({BindingType->getCanonicalType(), Source});

test/IRGen/reflection_metadata.swift

@@ -38,7 +38,9 @@
 // CHECK-DAG: private constant [3 x i8] c"GS\00", section "{{[^"]*}}swift3_reflstr{{[^"]*}}"
 // CHECK-DAG: private constant [3 x i8] c"GE\00", section "{{[^"]*}}swift3_reflstr{{[^"]*}}"
 
-// CHECK: @"\01l__swift3_reflection_metadata{{.*}}" = private constant <{ {{.*}} }>
+// CHECK-DAG: @"\01l__swift3_capture_descriptor" = private constant <{ {{.*}} }> <{ i32 1, i32 1, i32 2, {{.*}} }>
+
+// CHECK-DAG: @"\01l__swift3_reflection_metadata{{.*}}" = private constant <{ {{.*}} }>
 
 public protocol MyProtocol {
   associatedtype Inner
@@ -101,7 +103,6 @@ public enum MyGenericEnum<T : MyProtocol> {
   case I(Int)
 }
 
-public func makeSomeClosures<T, U>(t: T, x: Int, y: MyGenericStruct<U>)
-    -> (() -> (), () -> (), () -> ()) {
-  return ({ _ = t }, { _ = x }, { _ = y })
+public func makeSomeClosures<T : MyProtocol>(t: T) -> (() -> ()) {
+  return { _ = t }
 }