[CodeComplete] Fix code completion of initialization for variable wrapped by generic property wrapper

lib/AST/Type.cpp

@@ -4108,6 +4108,13 @@ TypeBase::getContextSubstitutions(const DeclContext *dc,
       continue;
     }
 
+    // There are no subtitutions to apply if the type is still unbound,
+    // continue looking into the parent.
+    if (auto unboundGeneric = baseTy->getAs<UnboundGenericType>()) {
+      baseTy = unboundGeneric->getParent();
+      continue;
+    }
+
     // Assert and break to avoid hanging if we get an unexpected baseTy.
     assert(0 && "Bad base type");
     break;

lib/Sema/TypeCheckPropertyWrapper.cpp

@@ -565,6 +565,8 @@ PropertyWrapperBackingPropertyTypeRequest::evaluate(
     (void)var->getInterfaceType();
     if (!binding->isInitializerChecked(index))
       TypeChecker::typeCheckPatternBinding(binding, index);
+    if (binding->isInvalid())
+      return Type();
   } else {
     using namespace constraints;
     auto dc = var->getInnermostDeclContext();

validation-test/IDE/crashers_2_fixed/rdar64141399-complete_generic_property_wrapper_initialization.swift

@@ -0,0 +1,35 @@
+// RUN: %target-swift-ide-test -code-completion -code-completion-token=COMPLETE_GENERIC -source-filename=%s
+// RUN: %target-swift-ide-test -code-completion -code-completion-token=COMPLETE_IN_GENERIC_CONTEXT -source-filename=%s
+
+struct Foo {
+  static let bar: Foo
+}
+
+@propertyWrapper public struct GenericWrapper<Value> {
+  public var wrappedValue: Value
+  public var projectedValue: Int
+
+  public init(wrappedValue: Value) {
+    self.wrappedValue = wrappedValue
+    self.projectedValue = 1
+  }
+}
+
+public struct GenericContext<T> {
+  @propertyWrapper public struct GenericWrapper<Value> {
+    public var wrappedValue: Value
+    public var projectedValue: Int
+
+    public init(wrappedValue: Value) {
+      self.wrappedValue = wrappedValue
+      self.projectedValue = 1
+    }
+  }
+}
+
+public struct MyStruct {
+  @GenericWrapper var someProperty = #^COMPLETE_GENERIC^#
+}
+public struct MyStruct2 {
+  @GenericContext<Foo>.GenericWrapper var someProperty2 = #^COMPLETE_IN_GENERIC_CONTEXT^#
+}