tvl-depot/tvix/eval
Florian Klink c9c8b10370 feat(tvix/eval): don't warn twice about dead code
We currently send two warnings in case of detecting dead code - W008
inside compile_dead_code, and a more detailed warning in all places that
invoke compile_dead_code:

```
warning[W007]: useless operation on boolean: this expression is always false
     --> /nix/store/qz3gjn95gazab4fkb7s8lm6hz17rdzzy-414z9nnj1wy66ymq6vgb693x9xjz6hf2-nixpkgs-src/pkgs/top-level/perl-packages.nix:12079:15
      |
12079 |     doCheck = false && !stdenv.isDarwin;
      |               ^^^^^^^^^^^^^^^^^^^^^^^^^

warning[W008]: this code will never be executed
     --> /nix/store/qz3gjn95gazab4fkb7s8lm6hz17rdzzy-414z9nnj1wy66ymq6vgb693x9xjz6hf2-nixpkgs-src/pkgs/top-level/perl-packages.nix:12079:24
      |
12079 |     doCheck = false && !stdenv.isDarwin;
      |                        ^^^^^^^^^^^^^^^^
```

The place invoking `compile_dead_code` has more context to why the code
is unused, so it's error message is much more useful.

Stop emitting the less informative warning inside compile_dead_code
(W008), and update the comment that we expect the caller to emit a
warning.

I kept W008 itself still around, in case we end up having places this
will get used again.

Change-Id: I2c5d84fc0cb4035872cd4b71cc3e9e34e120eb37
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8024
Tested-by: BuildkiteCI
Autosubmit: flokli <flokli@flokli.de>
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
2023-03-11 14:26:49 +00:00
..
benches fix(tvix/eval): fix current clippy warnings 2022-12-25 18:25:06 +00:00
builtin-macros feat(tvix/eval): let builtin macro capture external state 2023-01-20 15:39:51 +00:00
docs docs(tvix/eval): add proposal for VM loop restructuring 2023-02-16 22:23:51 +00:00
proptest-regressions/value test(tvix/eval): Add tests for the Eq laws of Value 2022-09-18 17:57:09 +00:00
src feat(tvix/eval): don't warn twice about dead code 2023-03-11 14:26:49 +00:00
tests feat(tvix/eval): use EvalIO::import_path when coercing paths 2022-12-21 22:59:18 +00:00
.skip-subtree feat(tvix/tests): check in Nix' language test suite 2022-08-24 21:25:41 +00:00
build.rs feat(tvix/eval): implement builtins.currentSystem 2022-10-24 12:20:01 +00:00
Cargo.toml feat(tvix/eval): introduce generators module 2023-03-07 22:04:59 +00:00
default.nix refactor(tvix): build Rust projects using crate2nix 2022-12-15 17:26:45 +00:00
README.md docs(tvix): move most of //tvix/eval README up to //tvix 2023-01-21 15:08:38 +00:00

Tvix Evaluator

This project implements an interpreter for the Nix programming language. You can experiment with an online version of the evaluator: tvixbolt.

The interpreter aims to be compatible with nixpkgs, on the foundation of Nix 2.3.

Important note: The evaluator is not yet feature-complete, and while the core mechanisms (compiler, runtime, ...) have stabilised somewhat, a lot of components are still changing rapidly.

Please contact TVL with any questions you might have.

Building tvix-eval

Please check the README.md one level up for instructions on how to build this.

The evaluator itself can also be built with standard Rust tooling (i.e. cargo build).

If you would like to clone only the evaluator and build it directly with Rust tooling, you can do:

git clone https://code.tvl.fyi/depot.git:/tvix/eval.git tvix-eval

cd tvix-eval && cargo build

Nix test suite

C++ Nix implements a language test suite in the form of Nix source code files, and their expected output. The coverage of this test suite is not complete, but we intend to be compatible with it.

We have ported the test suite to Tvix, but do not run it by default as we are not yet compatible with it.

You can run the test suite by enabling the nix_tests feature in Cargo:

cargo test --features nix_tests

rnix-parser

Tvix is written in memory of jD91mZM2, the author of rnix-parser who sadly passed away.

Tvix makes heavy use of rnix-parser in its bytecode compiler. The parser is now maintained by Nix community members.