Open Radar

 
Summary:
Provide a descriptive summary of the issue.

Steps to Reproduce:
This code:
func s() {
	var f: () -> () = {}
	let _: (() -> ()) -> () = { g in
		let _f = f
		f = {
			_f()
			g()
		}
	}
}

Expected Results:
shouldn’t crash swiftc

Actual Results:
but totally does:
rob@Resonance ~/Desktop> swiftc boom.swift; and ./boom
argument type mismatch!
  argument:   %1 = argument of bb0 : $@box @callee_owned () -> () // user: %13
  expected: $@box (() -> ())
SIL verification failed: entry point argument types do not match function type: std::equal(entry->bbarg_begin(), entry->bbarg_end(), ti->getParameterSILTypes().begin(), [&](SILArgument *bbarg, SILType ty) { auto mappedTy = F.mapTypeIntoContext(ty); if (bbarg->getType() != mappedTy) { llvm::errs() << "argument type mismatch!\n"; llvm::errs() << "  argument: "; bbarg->dump(); llvm::errs() << "  expected: "; mappedTy.dump(); return false; } return true; })
In function:
// boom.(s () -> ()).(closure #2)
sil shared @_TFF4boom1sFT_T_U0_FFT_T_T_ : $@convention(thin) (@owned @callee_owned () -> (), @owned @box (() -> ()), @inout @callee_owned () -> ()) -> () {
bb0(%0 : $@callee_owned () -> (), %1 : $@box @callee_owned () -> (), %2 : $*@callee_owned () -> ()):
  debug_value %0 : $@callee_owned () -> ()  // let g // id: %3
  %4 = load %2 : $*@callee_owned () -> ()         // users: %5, %6, %8, %10, %12
  strong_retain %4 : $@callee_owned () -> ()      // id: %5
  debug_value %4 : $@callee_owned () -> ()  // let _f // id: %6
  // function_ref boom.(s () -> ()).(closure #2).(closure #1)
  %7 = function_ref @_TFFF4boom1sFT_T_U0_FFT_T_T_U_FT_T_ : $@convention(thin) (@owned @callee_owned () -> (), @owned @callee_owned () -> ()) -> () // user: %10
  strong_retain %4 : $@callee_owned () -> ()      // id: %8
  strong_retain %0 : $@callee_owned () -> ()      // id: %9
  %10 = partial_apply %7(%4, %0) : $@convention(thin) (@owned @callee_owned () -> (), @owned @callee_owned () -> ()) -> () // user: %11
  assign %10 to %2 : $*@callee_owned () -> ()     // id: %11
  strong_release %4 : $@callee_owned () -> ()     // id: %12
  strong_release %1 : $@box @callee_owned () -> () // id: %13
  strong_release %0 : $@callee_owned () -> ()     // id: %14
  %15 = tuple ()                                  // user: %16
  return %15 : $()                                // id: %16
}

0  swift                    0x000000010ebbeb8b llvm::sys::PrintStackTrace(__sFILE*) + 43
1  swift                    0x000000010ebbf2cb SignalHandler(int) + 379
2  libsystem_platform.dylib 0x00007fff85ef3eaa _sigtramp + 26
3  swift                    0x000000010f1bda87 FirstTarget + 61919
4  swift                    0x000000010ebbf0c6 abort + 22
5  swift                    0x000000010cd6b239 (anonymous namespace)::SILVerifier::_require(bool, llvm::Twine const&, std::__1::function<void ()> const&) + 425
6  swift                    0x000000010cd682d0 swift::SILFunction::verify() const + 2336
7  swift                    0x000000010cda9c70 swift::Lowering::SILGenModule::emitClosure(swift::AbstractClosureExpr*) + 256
8  swift                    0x000000010ce000eb (anonymous namespace)::RValueEmitter::visitAbstractClosureExpr(swift::AbstractClosureExpr*, swift::Lowering::SGFContext) + 107
9  swift                    0x000000010cdf5f47 swift::ASTVisitor<(anonymous namespace)::RValueEmitter, swift::Lowering::RValue, void, void, void, void, void, swift::Lowering::SGFContext>::visit(swift::Expr*, swift::Lowering::SGFContext) + 151
10 swift                    0x000000010cdef66f swift::Lowering::SILGenFunction::emitExprInto(swift::Expr*, swift::Lowering::Initialization*) + 303
11 swift                    0x000000010cddfd08 swift::Lowering::SILGenFunction::visitPatternBindingDecl(swift::PatternBindingDecl*) + 232
12 swift                    0x000000010ce4326a swift::ASTVisitor<(anonymous namespace)::StmtEmitter, void, void, void, void, void, void>::visit(swift::Stmt*) + 362
13 swift                    0x000000010ce430f5 swift::Lowering::SILGenFunction::emitStmt(swift::Stmt*) + 21
14 swift                    0x000000010ce0a496 swift::Lowering::SILGenFunction::emitFunction(swift::FuncDecl*) + 390
15 swift                    0x000000010cda8131 swift::Lowering::SILGenModule::emitFunction(swift::FuncDecl*) + 513
16 swift                    0x000000010cdb001f swift::ASTVisitor<swift::Lowering::SILGenModule, void, void, void, void, void, void>::visit(swift::Decl*) + 255
17 swift                    0x000000010cdac14b swift::Lowering::SILGenModule::emitSourceFile(swift::SourceFile*, unsigned int) + 587
18 swift                    0x000000010cdacfdf swift::SILModule::constructSIL(swift::ModuleDecl*, swift::SILOptions&, swift::FileUnit*, llvm::Optional<unsigned int>, bool, bool) + 975
19 swift                    0x000000010cdad43b swift::performSILGeneration(swift::FileUnit&, swift::SILOptions&, llvm::Optional<unsigned int>, bool) + 123
20 swift                    0x000000010cba4c61 performCompile(swift::CompilerInstance&, swift::CompilerInvocation&, llvm::ArrayRef<char const*>, int&) + 9569
21 swift                    0x000000010cba24e3 frontend_main(llvm::ArrayRef<char const*>, char const*, void*) + 2627
22 swift                    0x000000010cb9e5af main + 2015
23 libdyld.dylib            0x00007fff942115ad start + 1
Stack dump:
0.	Program arguments: /Applications/Xcode-beta.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swift -frontend -c -primary-file boom.swift -target x86_64-apple-darwin15.0.0 -enable-objc-interop -sdk /Applications/Xcode-beta.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.11.sdk -color-diagnostics -module-name boom -o /var/folders/9y/f7n4rvx901nctm_5d16c1wm40000gn/T/boom-6bb0c8.o 
1.	While emitting SIL for 's' at boom.swift:1:1
2.	While silgen closureexpr SIL function @_TFF4boom1sFT_T_U0_FFT_T_T_ for expression at [boom.swift:3:28 - line:9:2] RangeText="{ g in
		let _f = f
		f = {
			_f()
			g()
		}
	}"
3.	While verifying SIL function @_TFF4boom1sFT_T_U0_FFT_T_T_ for expression at [boom.swift:3:28 - line:9:2] RangeText="{ g in
		let _f = f
		f = {
			_f()
			g()
		}
	}"
<unknown>:0: error: unable to execute command: Illegal instruction: 4
<unknown>:0: error: swift frontend command failed due to signal (use -v to see invocation)


Regression:
N/A

Notes:
N/A