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Issue Description:

I'm seeing a crash with the following synopsis:

Assertion failed: (FoundCXX && "Record type mismatch"), function VisitRecordDecl, file /Users/buildnode/jenkins/workspace/oss-swift-package-osx/llvm/tools/clang/lib/AST/ASTImporter.cpp, line 2678.

I've been able to reliably cause LLDB to crash when debugging an app that uses multiple static libraries, where at least 1 static library is Swift based and depends on a different Objective-C based static library. The important steps for repro are: disable serialize debugging options and rely on a struct from iOS SDK (e.g. CGRect, UIEdgeInsets) in the Objective-C code. I'm attaching a crash report from LLDB and an example Xcode project that demonstrates the crash.

In my Xcode project, I've used a xcconfig to set -no-serialize-debug-options for the Swift components and customized the Swift import paths to find a modulemap file for the Objective-C based static library. This is configured to be as similar as possible to my "real" projects that use Bazel.

The Xcode project includes:

1. An app target with an empty Swift file, this is just to link together the relevant static libraries.
2. A Swift based static library, AppLibrary, that includes the app's AppDelegate.
3. An Objective-C based static library, CoreLibrary, which includes an Objective-C view controller. This implementation includes a method whose signature includes a CGRect, which seems to be part of the root cause of the LLDB crash.

I repro'd this on the latest available toolchain snapshot, from 11/6/19.

I believe this is specific to Swift's LLDB because there are no issues with similar pure Objective-C projects.