struct Movie2 {
    let character: Int?
}

// RUN: %refactor -convert-to-async -dump-text -source-filename %s -pos=%(line+1):6
func peoplesStateReducer() {
    let cast: [Movie2] = []
    for meta in cast where meta.character != nil {
    }
}

Stack dump without symbol names (ensure you have llvm-symbolizer in your PATH or set the environment var `LLVM_SYMBOLIZER_PATH` to point to it):
0  swift-refactor           0x0000000112b48dc7 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) + 39
1  swift-refactor           0x0000000112b47be8 llvm::sys::RunSignalHandlers() + 248
2  swift-refactor           0x0000000112b493f6 SignalHandler(int) + 262
3  libsystem_platform.dylib 0x00007fff20365d7d _sigtramp + 29
4  libsystem_platform.dylib 0x00007ffee1a8f768 _sigtramp + 18446744072660097544
5  swift-refactor           0x000000010f9d3215 void llvm::SmallVectorImpl<char>::append<char const*, void>(char const*, char const*) + 149
6  swift-refactor           0x0000000112b2e403 llvm::raw_ostream::write(char const*, unsigned long) + 643
7  swift-refactor           0x000000010e1f0d6e (anonymous namespace)::asyncrefactorings::AsyncConverter::walkToExprPre(swift::Expr*) + 1230
8  swift-refactor           0x000000010e215a18 (anonymous namespace)::SemaAnnotator::walkToExprPre(swift::Expr*) + 232
9  swift-refactor           0x000000010f0f14a5 swift::ASTVisitor<(anonymous namespace)::Traversal, swift::Expr*, swift::Stmt*, bool, swift::Pattern*, bool, void>::visit(swift::Stmt*) + 3093
10 swift-refactor           0x000000010f0f09ff swift::ASTVisitor<(anonymous namespace)::Traversal, swift::Expr*, swift::Stmt*, bool, swift::Pattern*, bool, void>::visit(swift::Stmt*) + 367
11 swift-refactor           0x000000010f0edc47 swift::Stmt::walk(swift::ASTWalker&) + 87
12 swift-refactor           0x000000010e2151e6 swift::SourceEntityWalker::walk(swift::Stmt*) + 278
13 swift-refactor           0x000000010e1f44be (anonymous namespace)::asyncrefactorings::AsyncConverter::convertNode(swift::ASTNode, swift::SourceLoc, bool) + 206
14 swift-refactor           0x000000010e1efd72 (anonymous namespace)::asyncrefactorings::AsyncConverter::convert() + 130
15 swift-refactor           0x000000010e1df7a8 (anonymous namespace)::RefactoringActionConvertToAsync::performChange() + 120
16 swift-refactor           0x000000010e1da130 swift::ide::refactorSwiftModule(swift::ModuleDecl*, swift::ide::RefactoringOptions, swift::ide::SourceEditConsumer&, swift::DiagnosticConsumer&) + 2672
17 swift-refactor           0x000000010e170f81 main + 3649
18 libdyld.dylib            0x00007fff2033bf3d start + 1