Open Radar

 
Summary:
Crash when I use the type-parametric getter of a @final class.


Steps to Reproduce:
1. Write this Box class:

@final class Box<T> {
	let value: T
	
	init(_ value: T) {
		self.value = value
	}
}

func f<T>(box: Box<T>) {
	let x = box.value
}

2. Compile it.


Expected Results:
I expected it to compile.


Actual Results:
The compiler crashed.


Regression:
You couldn’t do non-fixed layouts at all in beta 2, so it’s new in that sense.
Workaround: remove `@final`.


Notes:
0  swift                    0x000000010779dde8 llvm::sys::PrintStackTrace(__sFILE*) + 40
1  swift                    0x000000010779e2d4 SignalHandler(int) + 452
2  libsystem_platform.dylib 0x00007fff8b6965aa _sigtramp + 26
3  libsystem_platform.dylib 0x000000000000001b _sigtramp + 1956027019
4  swift                    0x0000000106b6fef7 swift::irgen::IRGenFunction::emitValueWitnessTableRefForMetadata(llvm::Value*) + 71
5  swift                    0x0000000106b9610d swift::irgen::emitInitializeWithCopyCall(swift::irgen::IRGenFunction&, llvm::Value*, llvm::Value*, llvm::Value*) + 45
6  swift                    0x0000000106bdc96c swift::SILVisitor<(anonymous namespace)::IRGenSILFunction, void>::visit(swift::ValueBase*) + 39260
7  swift                    0x0000000106bd2800 swift::irgen::IRGenModule::emitSILFunction(swift::SILFunction*) + 8896
8  swift                    0x0000000106b53d18 swift::irgen::IRGenModule::emitGlobalTopLevel() + 200
9  swift                    0x0000000106bbf575 performIRGeneration(swift::IRGenOptions&, swift::Module*, swift::SILModule*, llvm::StringRef, llvm::LLVMContext&, swift::SourceFile*, unsigned int) + 1829
10 swift                    0x0000000106bbee3a swift::performIRGeneration(swift::IRGenOptions&, swift::Module*, swift::SILModule*, llvm::StringRef, llvm::LLVMContext&) + 42
11 swift                    0x0000000106cfb130 swift::RunImmediately(swift::CompilerInstance&, std::__1::vector<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > > const&, swift::IRGenOptions&, swift::SILOptions const&) + 128
12 swift                    0x0000000106b31cd3 frontend_main(llvm::ArrayRef<char const*>, char const*, void*) + 5283
13 swift                    0x0000000106b3081d main + 1533
14 libdyld.dylib            0x00007fff94bc25fd start + 1
15 libdyld.dylib            0x000000000000000b start + 1799608847
Stack dump:
0.	Program arguments: /Applications/Xcode6-Beta3.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swift -frontend -i ./Test.swift -enable-objc-attr-requires-objc-module -target x86_64-apple-darwin13.3.0 -module-name Test -sdk /Applications/Xcode6-Beta3.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk 
1.	While emitting IR SIL function @_TF4Test1fU__FGCS_3BoxQ__T_ for 'f' at ./Test.swift:11:1