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Matt Godbolt sold me on Rust by showing me C++

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611 points LorenDB | 1 comments | 06 May 25 17:51 UTC | HN request time: 0s | source
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grumbel ◴[06 May 25 18:33 UTC] No.43908210[source]▶
There is '-Wconversion' to catch things like this. It will however not trigger in this specific case since g++ assumes converting 1000.0 to 1000 is ok due to no loss in precision.

Quantity(100) is counterproductive here, as that doesn't narrow the type, it does the opposite, it casts whatever value is given to the type, so even Quantity(100.5) will still work, while just plain 100.5 would have given an error with '-Wconversion'.

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b5n ◴[06 May 25 19:04 UTC] No.43908555[source]▶
> -Wconversion ... assumes converting 1000.0 to 1000 is ok due to no loss in precision.

Additionally, `clang-tidy` catches this via `bugprone-narrowing-conversions` and your linter will alert if properly configured.

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kelnos ◴[06 May 25 19:25 UTC] No.43908717[source]▶
My opinion is that if you need to run extra tools/linters in order to catch basic errors, the language & its compiler are not doing enough to protect me from correctness bugs.

I do run clippy on my Rust projects, but that's a matter of style and readability, not correctness (for the most part!).

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1. uecker ◴[07 May 25 07:07 UTC] No.43912990[source]▶
The reason certain warnings are on or off by default in compilers in certain warnings modes depends on whether enough people find them useful enough or not. Rust caters to people who want strictness which makes it annoying to use for others, but if you want this you can also - to a large degree - have this in C and C++.