cpp-typecheck

A command line tool to type check a C++ source file with a clang compilation database.

cpp-typecheck extracts the compiler command for the given source file from the database, executes it and outputs the output of the compiler.

The design of cpp-typecheck was to get the most minimal program, that doesn't need any configuration, should just work and is easy to integrate into editors.

The database contains the compiler commands - with all flags, defines and includes - of all source files of the project. The easiest way to get a database is for a cmake build project by calling cmake with the option -DCMAKE_EXPORT_COMPILE_COMMANDS=ON. After the complete rebuild of the project the root of the build directory will contain a database named compile_commands.json.

There're several programs operating with a database and also doing type checking, like rtags or YouCompleteMe, but either - in the case of rtags - they do the type checking asynchronously, which makes it harder to integrate into several editors or - in the case of YouCompleteMe - they feel quite a bit heavyweight, are harder to configure and slow done my prefered editor vim quite a bit.

Another issue is, that these programs sometimes use clang for the type checking and not the compiler used in the database, which might give different warnings for the type checking and the building, which sometimes isn't the desired behaviour.

cpp-typecheck isn't the best fit for on the fly type checking - here the asynchronously solutions are more appropriate - it is meant for synchronous on demand type checking - by pressing some editor shortcut - with minimal hassle to configure.

Installation

cpp-typecheck is build with Rust so at least rustc and cargo are needed to build it.

The easiest way to get both is by using rustup:

$> curl https://sh.rustup.rs -sSf | sh

After this call you should have a rustc and cargo binary available at ~/.cargo/bin/, so adding this path to the PATH enviroment variable is recommendable.

For non unix like platforms take a look at here.

And now building and installing cpp-typecheck:

$> cargo install cpp-typecheck

The build binary will be located at ~/.cargo/bin/cpp-typecheck.

Usage

Type checking a source file:

$> cpp-typecheck  /absolute_path_to/SomeSource.cpp

This will search for a database named compile_commands.json upwards the directory tree starting at the directory /absolute_path_to/. Then SomeSource.cpp is looked up in the database, the compiler command is executed and the compiler output is output.

This makes it possible to use cpp-typecheck as a compiler replacement in editors that parse the output of the compiler and display the errors.

If the database isn't reachable through the source file directory then the database has also to be given:

$> cpp-typecheck  /absolute_path_to/SomeSource.cpp  path_to/compile_commands.json

It's also possible to use an other compiler for the type checking than the one defined in the database, as long as the compiler arguments are compatible (which is the case for gcc and clang):

$> cpp-typecheck  --compiler clang  /absolute_path_to/SomeSource.cpp

Text Editor Integration

vim-cpp-typecheck

Possible Issues

The compiler commands for source files are cached at ~/.cpp_typecheck/cache/cmds, so that multiple type checks of the same source don't need to look up the command again in the database. Normally this shouldn't be an issue, because the commands in the database very rarely change in a way that affects type checking, but if there're problems, then the cache at ~/.cpp_typecheck/cache/cmds can be just cleared.

There's also the option --no-cache to ignore the cache and to always lookup the compiler command in the database.