[BUG]: mojo crash: Assertion `size() >= N && "Dropping more elements than exist"' failed.

[junweizeng]

Bug description

mojo crashes on the following code (i.e. test.mojo).

import object
def main():

Steps to reproduce

$ mojo build test.mojo
/path/to/test.mojo:1:8: error: unable to locate module 'object'
import object
       ^
mojo: /__w/modular/modular/third-party/llvm-project/llvm/include/llvm/ADT/ArrayRef.h:205: ArrayRef<T> llvm::ArrayRef<mlir::Type>::drop_front(size_t) const [T = mlir::Type]: Assertion `size() >= N && "Dropping more elements than exist"' failed.
Please submit a bug report to https://github.com/modularml/mojo/issues and include the crash backtrace along with all the relevant source codes.
Stack dump:
0.      Program arguments: mojo build test.mojo
1.      Crash resolving decl signature at loc("/path/to/test.mojo":2:5)
    >> def main():
           ^......<
 #0 0x0000557eb9f73f57 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/home/jwzeng/.modular/pkg/packages.modular.com_mojo/bin/mojo+0x1c32f57)
 #1 0x0000557eb9f71b2e llvm::sys::RunSignalHandlers() (/home/jwzeng/.modular/pkg/packages.modular.com_mojo/bin/mojo+0x1c30b2e)
 #2 0x0000557eb9f745ef SignalHandler(int) (/home/jwzeng/.modular/pkg/packages.modular.com_mojo/bin/mojo+0x1c335ef)
 #3 0x00007f5a8f62e520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #4 0x00007f5a8f682a7c __pthread_kill_implementation ./nptl/pthread_kill.c:44:76
 #5 0x00007f5a8f682a7c __pthread_kill_internal ./nptl/pthread_kill.c:78:10
 #6 0x00007f5a8f682a7c pthread_kill ./nptl/pthread_kill.c:89:10
 #7 0x00007f5a8f62e476 gsignal ./signal/../sysdeps/posix/raise.c:27:6
 #8 0x00007f5a8f6147f3 abort ./stdlib/abort.c:81:7
 #9 0x00007f5a8f61471b _nl_load_domain ./intl/loadmsgcat.c:1177:9
#10 0x00007f5a8f625e96 (/lib/x86_64-linux-gnu/libc.so.6+0x39e96)
#11 0x0000557eba36134c M::KGEN::LIT::DeclResolver::exportMain(M::KGEN::LIT::ASTDecl&) (/home/jwzeng/.modular/pkg/packages.modular.com_mojo/bin/mojo+0x202034c)
#12 0x0000557eba34b415 M::KGEN::LIT::DeclResolver::resolveSignature(M::KGEN::LIT::FuncOp, M::KGEN::LIT::Lexer&, M::KGEN::LIT::ASTDecl&) (/home/jwzeng/.modular/pkg/packages.modular.com_mojo/bin/mojo+0x200a415)
#13 0x0000557eba35ebce M::KGEN::LIT::DeclResolver::resolve(M::KGEN::LIT::ASTDecl&, M::KGEN::LIT::DeclResolvedness, llvm::SMLoc) (/home/jwzeng/.modular/pkg/packages.modular.com_mojo/bin/mojo+0x201dbce)
#14 0x0000557eba35f6a8 M::KGEN::LIT::DeclResolver::resolveAllReferencedFrom(M::KGEN::LIT::ASTDecl&) (/home/jwzeng/.modular/pkg/packages.modular.com_mojo/bin/mojo+0x201e6a8)
#15 0x0000557eba36a2a2 importMojoImpl(M::LLCL::Runtime&, llvm::StringRef, llvm::SourceMgr&, M::KGEN::LIT::SharedState&, mlir::TimingScope&, llvm::SmallVectorImpl<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>>*, llvm::function_ref<M::KGEN::LIT::ASTDecl& (mlir::ModuleOp)>) (/home/jwzeng/.modular/pkg/packages.modular.com_mojo/bin/mojo+0x20292a2)
#16 0x0000557eba36a62d M::KGEN::LIT::importMojoFile(M::LLCL::Runtime&, llvm::SourceMgr&, M::KGEN::LIT::ParserConfig&, mlir::TimingScope&, llvm::SmallVectorImpl<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>>*) (/home/jwzeng/.modular/pkg/packages.modular.com_mojo/bin/mojo+0x202962d)
#17 0x0000557eb9e8bb0c mlir::OwningOpRef<mlir::ModuleOp> llvm::function_ref<mlir::OwningOpRef<mlir::ModuleOp> (M::KGEN::LIT::ParserConfig&, mlir::TimingScope&)>::callback_fn<build(M::State const&)::$_2>(long, M::KGEN::LIT::ParserConfig&, mlir::TimingScope&) (/home/jwzeng/.modular/pkg/packages.modular.com_mojo/bin/mojo+0x1b4ab0c)
#18 0x0000557eb9e8e111 M::invokeMojoParser(M::State const&, llvm::opt::InputArgList const&, M::KGEN::CompilationOptions&, mlir::MLIRContext*, M::LLCL::Runtime&, llvm::opt::OptSpecifier, llvm::opt::OptSpecifier, llvm::opt::OptSpecifier, llvm::function_ref<mlir::OwningOpRef<mlir::ModuleOp> (M::KGEN::LIT::ParserConfig&, mlir::TimingScope&)>) (/home/jwzeng/.modular/pkg/packages.modular.com_mojo/bin/mojo+0x1b4d111)
#19 0x0000557eb9e894c9 build(M::State const&) (/home/jwzeng/.modular/pkg/packages.modular.com_mojo/bin/mojo+0x1b484c9)
#20 0x0000557eb9e87ade main (/home/jwzeng/.modular/pkg/packages.modular.com_mojo/bin/mojo+0x1b46ade)
#21 0x00007f5a8f615d90 __libc_start_call_main ./csu/../sysdeps/nptl/libc_start_call_main.h:58:16
#22 0x00007f5a8f615e40 call_init ./csu/../csu/libc-start.c:128:20
#23 0x00007f5a8f615e40 __libc_start_main ./csu/../csu/libc-start.c:379:5
#24 0x0000557eb9e8742e _start (/home/jwzeng/.modular/pkg/packages.modular.com_mojo/bin/mojo+0x1b4642e)
0x557ebcd70238 crashed!
Please file a bug report.
Aborted

System information

$ lsb_release -a
LSB Version:    core-11.1.0ubuntu2-noarch:security-11.1.0ubuntu2-noarch
Distributor ID: Ubuntu
Description:    Ubuntu 22.04 LTS
Release:        22.04
Codename:       jammy
$ mojo -v
mojo 24.2.1 (2f0dcf11)
$ modular -v
modular 0.7.2 (d0adc668)

[junweizeng]

This bug seems to have been fixed on nightly/mojo. The retest process is as follows:

$ cat test.mojo
import object
def main():
$
$ mojo -v
mojo 2024.4.2923 (f54d89e3)
$
$ mojo build test.mojo
/path/to/test.mojo:1:8: error: unable to locate module 'object'
import object
       ^
mojo: error: failed to parse the provided Mojo source module