206b1a1ac9
This commit introduces a check to ensure that the lint won't trigger when the initializer is
unreachable, such as:
```
thread_local! {
static STATE: Cell<usize> = panic!();
}
```
This is achieved by looking at the unpeeled initializer expression and ensuring that the parent
macro is not `panic!()`, `todo!()`, `unreachable!()`, `unimplemented!()`.
fixes #12637
changelog: [`threadlocal_initializer_can_be_made_const`] will no longer trigger on `unreachable` macros.
76 lines
2.4 KiB
Rust
76 lines
2.4 KiB
Rust
#![warn(clippy::thread_local_initializer_can_be_made_const)]
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use std::cell::{Cell, RefCell};
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fn main() {
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// lint and suggest const
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thread_local! {
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static BUF_1: RefCell<String> = RefCell::new(String::new());
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}
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//~^^ ERROR: initializer for `thread_local` value can be made `const`
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// don't lint
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thread_local! {
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static BUF_2: RefCell<String> = const { RefCell::new(String::new()) };
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}
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thread_local! {
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static SIMPLE:i32 = 1;
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}
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//~^^ ERROR: initializer for `thread_local` value can be made `const`
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// lint and suggest const for all non const items
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thread_local! {
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static BUF_3_CAN_BE_MADE_CONST: RefCell<String> = RefCell::new(String::new());
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static CONST_MIXED_WITH:i32 = const { 1 };
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static BUF_4_CAN_BE_MADE_CONST: RefCell<String> = RefCell::new(String::new());
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}
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//~^^^^ ERROR: initializer for `thread_local` value can be made `const`
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//~^^^ ERROR: initializer for `thread_local` value can be made `const`
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thread_local! {
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static PEEL_ME: i32 = { 1 };
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//~^ ERROR: initializer for `thread_local` value can be made `const`
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static PEEL_ME_MANY: i32 = { let x = 1; x * x };
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//~^ ERROR: initializer for `thread_local` value can be made `const`
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}
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}
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fn issue_12637() {
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/// The set methods on LocalKey<Cell<T>> and LocalKey<RefCell<T>> are
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/// guaranteed to bypass the thread_local's initialization expression.
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/// See rust-lang/rust#92122. Thus, = panic!() is a useful idiom for
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/// forcing the use of set on each thread before it accesses the thread local in any other
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/// manner.
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thread_local! {
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static STATE_12637_PANIC: Cell<usize> = panic!();
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}
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STATE_12637_PANIC.set(9);
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println!("{}", STATE_12637_PANIC.get());
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thread_local! {
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static STATE_12637_TODO: Cell<usize> = todo!();
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}
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STATE_12637_TODO.set(9);
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println!("{}", STATE_12637_TODO.get());
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thread_local! {
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static STATE_12637_UNIMPLEMENTED: Cell<usize> = unimplemented!();
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}
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STATE_12637_UNIMPLEMENTED.set(9);
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println!("{}", STATE_12637_UNIMPLEMENTED.get());
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thread_local! {
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static STATE_12637_UNREACHABLE: Cell<usize> = unreachable!();
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}
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STATE_12637_UNREACHABLE.set(9);
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println!("{}", STATE_12637_UNREACHABLE.get());
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}
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#[clippy::msrv = "1.58"]
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fn f() {
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thread_local! {
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static TLS: i32 = 1;
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}
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}
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