Unhandled exception discovered in the Neon REPL. (Windows only)

[gitlarryf]

Typing the following lines in the REPL:

VAR d: Dictionary<Number> := { "10": 10, "20": 20 }
print(d[100])

Will cause an unhandled exception in Windows vcruntime140.dll.
Unhandled exception at 0x00007FF819B41416 (vcruntime140d.dll) in neon.exe: 0xC0000005: Access violation reading location 0xFFFFFFFFFFFFFFFF. occurred
The exception happens on line 26 of lexer.cpp, and appears to be some sort of uninitialized variable, resulting in a std::bad_alloc() attempting to be thrown.

Stack trace

 	ucrtbased.dll!issue_debug_notification(const wchar_t * const message) Line 28	C++
 	ucrtbased.dll!__acrt_report_runtime_error(const wchar_t * message) Line 154	C++
 	ucrtbased.dll!abort() Line 61	C++
 	ucrtbased.dll!terminate() Line 59	C++
 	neon.exe!__scrt_unhandled_exception_filter(_EXCEPTION_POINTERS * const pointers) Line 94	C++
 	KernelBase.dll!UnhandledExceptionFilter�()	Unknown
 	ntdll.dll!RtlUserThreadStart$filt$0()	Unknown
 	ntdll.dll!__C_specific_handler�()	Unknown
 	ntdll.dll!RtlpExecuteHandlerForException�()	Unknown
 	ntdll.dll!RtlDispatchException()	Unknown
 	ntdll.dll!RtlRaiseException�()	Unknown
 	KernelBase.dll!RaiseException�()	Unknown
 	vcruntime140d.dll!_CxxThrowException(void * pExceptionObject, const _s__ThrowInfo * pThrowInfo) Line 75	C++
>	neon.exe!__scrt_throw_std_bad_alloc() Line 36	C++
 	neon.exe!operator new(unsigned __int64 size) Line 53	C++
 	neon.exe!std::_Default_allocate_traits::_Allocate(const unsigned __int64 _Bytes) Line 53	C++
 	neon.exe!std::_Allocate_manually_vector_aligned(const unsigned __int64 _Bytes) Line 100	C++
 	neon.exe!std::_Allocate<16,std::_Default_allocate_traits,0>(const unsigned __int64 _Bytes) Line 184	C++
 	neon.exe!std::allocator::allocate(const unsigned __int64 _Count) Line 998	C++
 	neon.exe!std::basic_string,std::allocator >::_Construct_lv_contents(const std::basic_string,std::allocator > & _Right) Line 2411	C++
 	neon.exe!std::basic_string,std::allocator >::basic_string,std::allocator >(const std::basic_string,std::allocator > & _Right) Line 2131	C++
 	neon.exe!Token::file() Line 26	C++
 	neon.exe!SourceErrorToken::SourceErrorToken(const Token & token) Line 30	C++
 	neon.exe!SourceError::SourceError(const std::basic_string,std::allocator > & compiler_file, int compiler_line, int number, const Token & token, const std::basic_string,std::allocator > & message, const Token & token2, const std::basic_string,std::allocator > & message2) Line 42	C++
 	neon.exe!abort_error(const char * compiler_file, int compiler_line, int number, const Token & token, const std::basic_string,std::allocator > & message, const Token & token2, const std::basic_string,std::allocator > & message2) Line 33	C++
 	neon.exe!Analyzer::analyze(const pt::SubscriptExpression * expr) Line 2618	C++
 	neon.exe!ExpressionAnalyzer::visit(const pt::SubscriptExpression * p) Line 304	C++
 	neon.exe!pt::SubscriptExpression::accept(pt::IParseTreeVisitor * visitor) Line 428	C++
 	neon.exe!Analyzer::analyze(const pt::Expression * expr) Line 2232	C++
 	neon.exe!Analyzer::analyze_function_call(const pt::FunctionCallExpression * expr, const ast::TypeFunction * ftype, const ast::Expression * self, const ast::Expression * dispatch, const std::vector > & initial_args, const ast::Expression * func, bool allow_ignore_result) Line 3038	C++
 	neon.exe!Analyzer::analyze(const pt::FunctionCallExpression * expr) Line 3298	C++
 	neon.exe!ExpressionAnalyzer::visit(const pt::FunctionCallExpression * p) Line 306	C++
 	neon.exe!pt::FunctionCallExpression::accept(pt::IParseTreeVisitor * visitor) Line 452	C++
 	neon.exe!Analyzer::analyze(const pt::Expression * expr) Line 2232	C++
 	neon.exe!Analyzer::analyze(const pt::FunctionCallExpression * expr) Line 3273	C++
 	neon.exe!ExpressionAnalyzer::visit(const pt::FunctionCallExpression * p) Line 306	C++
 	neon.exe!pt::FunctionCallExpression::accept(pt::IParseTreeVisitor * visitor) Line 452	C++
 	neon.exe!Analyzer::analyze(const pt::Expression * expr) Line 2232	C++
 	neon.exe!Analyzer::analyze_function_call(const pt::FunctionCallExpression * expr, const ast::TypeFunction * ftype, const ast::Expression * self, const ast::Expression * dispatch, const std::vector > & initial_args, const ast::Expression * func, bool allow_ignore_result) Line 3038	C++
 	neon.exe!Analyzer::analyze(const pt::FunctionCallExpression * expr) Line 3298	C++
 	neon.exe!ExpressionAnalyzer::visit(const pt::FunctionCallExpression * p) Line 306	C++
 	neon.exe!pt::FunctionCallExpression::accept(pt::IParseTreeVisitor * visitor) Line 452	C++
 	neon.exe!Analyzer::analyze(const pt::Expression * expr) Line 2232	C++
 	neon.exe!Analyzer::analyze(const pt::ExpressionStatement * statement) Line 6106	C++
 	neon.exe!StatementAnalyzer::visit(const pt::ExpressionStatement * p) Line 548	C++
 	neon.exe!pt::ExpressionStatement::accept(pt::IParseTreeVisitor * visitor) Line 910	C++
 	neon.exe!Analyzer::analyze(const std::vector >,std::allocator > > > & statement) Line 4918	C++
 	neon.exe!Analyzer::analyze() Line 7078	C++
 	neon.exe!analyze(ICompilerSupport * support, const pt::Program * program, std::map,std::allocator >,ast::ExternalGlobalInfo,std::less,std::allocator > >,std::allocator,std::allocator > const ,ast::ExternalGlobalInfo> > > * external_globals) Line 7597	C++
 	neon.exe!Repl::handle(const std::basic_string,std::allocator > & s) Line 91	C++
 	neon.exe!repl(int argc, char * * argv, const ExecOptions & options) Line 80	C++
 	neon.exe!main(int argc, char * * argv) Line 154	C++
 	[External Code]	

Note: This happens in both a release and a debug build.