clippy::trivial_regex: Checks for trivial regex creation (with Regex::new, RegexBuilder::new, or RegexSet::new)

Regex::new("^foobar")

str::starts_with("foobar")

[lints.clippy]
trivial_regex = "warn"

#![warn(clippy::trivial_regex)]

cargo clippy -- -W clippy::trivial-regex

Clippy's own documentation

What it does

Checks for trivial regex creation (with Regex::new, RegexBuilder::new, or RegexSet::new).

Why is this bad?

Matching the regex can likely be replaced by == or str::starts_with, str::ends_with or std::contains or other str methods.

Known problems

If the same regex is going to be applied to multiple inputs, the precomputations done by Regex construction can give significantly better performance than any of the str-based methods.

Example

Regex::new("^foobar")

Use instead:

str::starts_with("foobar")

From the Clippy lint list (0.1.99), part of the Rust project, MIT or Apache-2.0. Official entry.

Related lints

• redundant_cloneChecks for a redundant clone() (and its relatives) which clones an owned value that is going to be dropped without further use
• trailing_empty_arraytrailing zero-sized array in a struct which is not marked with a `repr` attribute
• trait_duplication_in_boundsthis trait bound is already specified in the where clause
• transmute_undefined_reprtransmute from `main::Foo<u32>` to `main::Foo<i32>`, both of which have an undefined layout
• tuple_array_conversionsit looks like you're trying to convert a tuple to an array
• type_repetition_in_boundstype `T` has already been used as a bound predicate
• uninhabited_referencesdereferencing a reference to an uninhabited type would be undefined behavior

All 847 Clippy lints · Rust compiler errors · Cargo.toml checker