rust/tests/ui/lint/unused/issue-30730.rs

#![warn(unused)]
#![deny(warnings)]
use std::thread;
//~^ ERROR: unused import
fn main() {}
rustc: Rearchitect lints to be emitted more eagerly In preparation for incremental compilation this commit refactors the lint handling infrastructure in the compiler to be more "eager" and overall more incremental-friendly. Many passes of the compiler can emit lints at various points but before this commit all lints were buffered in a table to be emitted at the very end of compilation. This commit changes these lints to be emitted immediately during compilation using pre-calculated lint level-related data structures. Linting today is split into two phases, one set of "early" lints run on the `syntax::ast` and a "late" set of lints run on the HIR. This commit moves the "early" lints to running as late as possible in compilation, just before HIR lowering. This notably means that we're catching resolve-related lints just before HIR lowering. The early linting remains a pass very similar to how it was before, maintaining context of the current lint level as it walks the tree. Post-HIR, however, linting is structured as a method on the `TyCtxt` which transitively executes a query to calculate lint levels. Each request to lint on a `TyCtxt` will query the entire crate's 'lint level data structure' and then go from there about whether the lint should be emitted or not. The query depends on the entire HIR crate but should be very quick to calculate (just a quick walk of the HIR) and the red-green system should notice that the lint level data structure rarely changes, and should hopefully preserve incrementality. Overall this resulted in a pretty big change to the test suite now that lints are emitted much earlier in compilation (on-demand vs only at the end). This in turn necessitated the addition of many `#![allow(warnings)]` directives throughout the compile-fail test suite and a number of updates to the UI test suite. 2017-07-26 21:51:09 -07:00			`#![warn(unused)]`
Remove NOTE/HELP annotations from UI tests 2017-12-10 23:29:24 +03:00			`#![deny(warnings)]`
note individual lint name set via lint group attribute in notes Warning or error messages set via a lint group attribute (e.g. `#[deny(warnings)]`) should still make it clear which individual lint (by name) was triggered, similarly to how we include "on by default" language for default lints. This—and, while we're here, the existing "on by default" language—can be tucked into a note rather than cluttering the main error message. This occasions the slightest of refactorings (we now have to get the diagnostic-builder with the main message first, before matching on the lint source). This is in the matter of #36846. 2017-01-05 18:55:36 -08:00			`use std::thread;`
			`//~^ ERROR: unused import`
Add compile fail test for #30730 2016-01-12 15:05:08 +00:00			`fn main() {}`