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Auto merge of #43522 - alexcrichton:rewrite-lints, r=michaelwoerister

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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.

Closes https://github.com/rust-lang/rust/issues/42511
This commit is contained in:
bors 2017-08-10 11:20:15 +00:00
commit 2400ebfe76
84 changed files with 1345 additions and 1067 deletions
Download patch file Download diff file Expand all files Collapse all files

3
src/test/ui/check_match/issue-43253.rs
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@ -9,6 +9,7 @@
// except according to those terms.
#![feature(exclusive_range_pattern)]
#![warn(unreachable_patterns)]
fn main() {
// These cases should generate no warning.
@ -48,4 +49,4 @@ fn main() {
9...9 => {},
_ => {},
}
}
}

18
src/test/ui/check_match/issue-43253.stderr
View file

@ -1,20 +1,24 @@
warning: unreachable pattern
--> $DIR/issue-43253.rs:36:9
--> $DIR/issue-43253.rs:37:9
|
36 | 9 => {},
37 | 9 => {},
| ^
|
= note: #[warn(unreachable_patterns)] on by default
note: lint level defined here
--> $DIR/issue-43253.rs:12:9
|
12 | #![warn(unreachable_patterns)]
| ^^^^^^^^^^^^^^^^^^^^
warning: unreachable pattern
--> $DIR/issue-43253.rs:42:9
--> $DIR/issue-43253.rs:43:9
|
42 | 8...9 => {},
43 | 8...9 => {},
| ^^^^^
warning: unreachable pattern
--> $DIR/issue-43253.rs:48:9
--> $DIR/issue-43253.rs:49:9
|
48 | 9...9 => {},
49 | 9...9 => {},
| ^^^^^

2
src/test/ui/compare-method/proj-outlives-region.stderr
View file

@ -1,4 +1,4 @@
error[E0276]: impl has stricter requirements than trait
error: impl has stricter requirements than trait
--> $DIR/proj-outlives-region.rs:19:5
|
14 | fn foo() where T: 'a;

2
src/test/ui/compare-method/region-unrelated.stderr
View file

@ -1,4 +1,4 @@
error[E0276]: impl has stricter requirements than trait
error: impl has stricter requirements than trait
--> $DIR/region-unrelated.rs:19:5
|
14 | fn foo() where T: 'a;

1
src/test/ui/lint/fn_must_use.rs
View file

@ -8,6 +8,7 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
#![warn(unused_must_use)]
struct MyStruct {
n: usize

14
src/test/ui/lint/fn_must_use.stderr
View file

@ -1,14 +1,18 @@
warning: unused return value of `need_to_use_this_value` which must be used: it's important
--> $DIR/fn_must_use.rs:29:5
--> $DIR/fn_must_use.rs:30:5
|
29 | need_to_use_this_value();
30 | need_to_use_this_value();
| ^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: #[warn(unused_must_use)] on by default
note: lint level defined here
--> $DIR/fn_must_use.rs:11:9
|
11 | #![warn(unused_must_use)]
| ^^^^^^^^^^^^^^^
warning: unused return value of `MyStruct::need_to_use_this_method_value` which must be used
--> $DIR/fn_must_use.rs:32:5
--> $DIR/fn_must_use.rs:33:5
|
32 | m.need_to_use_this_method_value();
33 | m.need_to_use_this_method_value();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

8
src/test/ui/lint/outer-forbid.rs
View file

@ -16,7 +16,13 @@
#![forbid(unused, non_snake_case)]
#[allow(unused, unused_variables, bad_style)]
#[allow(unused_variables)]
fn foo() {}
#[allow(unused)]
fn bar() {}
#[allow(bad_style)]
fn main() {
println!("hello forbidden world")
}

24
src/test/ui/lint/outer-forbid.stderr
View file

@ -1,29 +1,29 @@
error[E0453]: allow(unused) overruled by outer forbid(unused)
error[E0453]: allow(unused_variables) overruled by outer forbid(unused)
--> $DIR/outer-forbid.rs:19:9
|
17 | #![forbid(unused, non_snake_case)]
| ------ `forbid` level set here
18 |
19 | #[allow(unused, unused_variables, bad_style)]
| ^^^^^^ overruled by previous forbid
19 | #[allow(unused_variables)]
| ^^^^^^^^^^^^^^^^ overruled by previous forbid
error[E0453]: allow(unused_variables) overruled by outer forbid(unused)
--> $DIR/outer-forbid.rs:19:17
error[E0453]: allow(unused) overruled by outer forbid(unused)
--> $DIR/outer-forbid.rs:22:9
|
17 | #![forbid(unused, non_snake_case)]
| ------ `forbid` level set here
18 |
19 | #[allow(unused, unused_variables, bad_style)]
| ^^^^^^^^^^^^^^^^ overruled by previous forbid
...
22 | #[allow(unused)]
| ^^^^^^ overruled by previous forbid
error[E0453]: allow(bad_style) overruled by outer forbid(non_snake_case)
--> $DIR/outer-forbid.rs:19:35
--> $DIR/outer-forbid.rs:25:9
|
17 | #![forbid(unused, non_snake_case)]
| -------------- `forbid` level set here
18 |
19 | #[allow(unused, unused_variables, bad_style)]
| ^^^^^^^^^ overruled by previous forbid
...
25 | #[allow(bad_style)]
| ^^^^^^^^^ overruled by previous forbid
error: aborting due to 3 previous errors

2
src/test/ui/path-lookahead.rs
View file

@ -10,6 +10,8 @@
// run-pass
#![warn(unused)]
// Parser test for #37765
fn with_parens<T: ToString>(arg: T) -> String { //~WARN function is never used: `with_parens`

27
src/test/ui/path-lookahead.stderr
View file

@ -1,26 +1,31 @@
warning: unnecessary parentheses around `return` value
--> $DIR/path-lookahead.rs:16:10
--> $DIR/path-lookahead.rs:18:10
|
16 | return (<T as ToString>::to_string(&arg)); //~WARN unnecessary parentheses around `return` value
18 | return (<T as ToString>::to_string(&arg)); //~WARN unnecessary parentheses around `return` value
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: #[warn(unused_parens)] on by default
warning: function is never used: `with_parens`
--> $DIR/path-lookahead.rs:15:1
--> $DIR/path-lookahead.rs:17:1
|
15 | / fn with_parens<T: ToString>(arg: T) -> String { //~WARN function is never used: `with_parens`
16 | | return (<T as ToString>::to_string(&arg)); //~WARN unnecessary parentheses around `return` value
17 | | }
17 | / fn with_parens<T: ToString>(arg: T) -> String { //~WARN function is never used: `with_parens`
18 | | return (<T as ToString>::to_string(&arg)); //~WARN unnecessary parentheses around `return` value
19 | | }
| |_^
|
= note: #[warn(dead_code)] on by default
note: lint level defined here
--> $DIR/path-lookahead.rs:13:9
|
13 | #![warn(unused)]
| ^^^^^^
= note: #[warn(dead_code)] implied by #[warn(unused)]
warning: function is never used: `no_parens`
--> $DIR/path-lookahead.rs:19:1
--> $DIR/path-lookahead.rs:21:1
|
19 | / fn no_parens<T: ToString>(arg: T) -> String { //~WARN function is never used: `no_parens`
20 | | return <T as ToString>::to_string(&arg);
21 | | }
21 | / fn no_parens<T: ToString>(arg: T) -> String { //~WARN function is never used: `no_parens`
22 | | return <T as ToString>::to_string(&arg);
23 | | }
| |_^

14
src/test/ui/reachable/expr_unary.stderr
View file

@ -1,8 +1,20 @@
error: unreachable expression
--> $DIR/expr_unary.rs:18:28
|
18 | let x: ! = ! { return; 22 };
| ^^
|
note: lint level defined here
--> $DIR/expr_unary.rs:14:9
|
14 | #![deny(unreachable_code)]
| ^^^^^^^^^^^^^^^^
error[E0600]: cannot apply unary operator `!` to type `!`
--> $DIR/expr_unary.rs:18:16
|
18 | let x: ! = ! { return; 22 };
| ^^^^^^^^^^^^^^^^
error: aborting due to previous error
error: aborting due to 2 previous errors

9
src/test/ui/span/issue-24690.rs
View file

@ -11,10 +11,13 @@
//! A test to ensure that helpful `note` messages aren't emitted more often
//! than necessary.
// Although there are three errors, we should only get two "lint level defined
// here" notes pointing at the `warnings` span, one for each error type.
#![deny(warnings)]
#![feature(rustc_attrs)]
// Although there are three warnings, we should only get two "lint level defined
// here" notes pointing at the `warnings` span, one for each error type.
#![warn(unused)]
#[rustc_error]
fn main() {
let theTwo = 2;
let theOtherTwo = 2;

53
src/test/ui/span/issue-24690.stderr
View file

@ -1,34 +1,37 @@
error: variable `theTwo` should have a snake case name such as `the_two`
--> $DIR/issue-24690.rs:19:9
warning: unused variable: `theOtherTwo`
--> $DIR/issue-24690.rs:23:9
|
19 | let theTwo = 2;
23 | let theOtherTwo = 2;
| ^^^^^^^^^^^
|
note: lint level defined here
--> $DIR/issue-24690.rs:18:9
|
18 | #![warn(unused)]
| ^^^^^^
= note: #[warn(unused_variables)] implied by #[warn(unused)]
warning: variable `theTwo` should have a snake case name such as `the_two`
--> $DIR/issue-24690.rs:22:9
|
22 | let theTwo = 2;
| ^^^^^^
|
note: lint level defined here
--> $DIR/issue-24690.rs:16:9
|
16 | #![deny(warnings)]
| ^^^^^^^^
= note: #[deny(non_snake_case)] implied by #[deny(warnings)]
= note: #[warn(non_snake_case)] on by default
error: variable `theOtherTwo` should have a snake case name such as `the_other_two`
--> $DIR/issue-24690.rs:20:9
warning: variable `theOtherTwo` should have a snake case name such as `the_other_two`
--> $DIR/issue-24690.rs:23:9
|
20 | let theOtherTwo = 2;
23 | let theOtherTwo = 2;
| ^^^^^^^^^^^
error: unused variable: `theOtherTwo`
--> $DIR/issue-24690.rs:20:9
error: compilation successful
--> $DIR/issue-24690.rs:21:1
|
20 | let theOtherTwo = 2;
| ^^^^^^^^^^^
|
note: lint level defined here
--> $DIR/issue-24690.rs:16:9
|
16 | #![deny(warnings)]
| ^^^^^^^^
= note: #[deny(unused_variables)] implied by #[deny(warnings)]
error: aborting due to 3 previous errors
21 | / fn main() {
22 | | let theTwo = 2;
23 | | let theOtherTwo = 2;
24 | | println!("{}", theTwo);
25 | | }
| |_^

2
src/test/ui/span/macro-span-replacement.rs
View file

@ -8,6 +8,8 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
#![warn(unused)]
macro_rules! m {
($a:tt $b:tt) => {
$b $a;

13
src/test/ui/span/macro-span-replacement.stderr
View file

@ -1,11 +1,16 @@
warning: struct is never used: `S`
--> $DIR/macro-span-replacement.rs:13:9
--> $DIR/macro-span-replacement.rs:15:9
|
13 | $b $a;
15 | $b $a;
| ^^^^^^
...
18 | m!(S struct);
20 | m!(S struct);
| ------------- in this macro invocation
|
= note: #[warn(dead_code)] on by default
note: lint level defined here
--> $DIR/macro-span-replacement.rs:11:9
|
11 | #![warn(unused)]
| ^^^^^^
= note: #[warn(dead_code)] implied by #[warn(unused)]

2
src/test/ui/span/multispan-import-lint.rs
View file

@ -8,6 +8,8 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
#![warn(unused)]
use std::cmp::{Eq, Ord, min, PartialEq, PartialOrd};
fn main() {

11
src/test/ui/span/multispan-import-lint.stderr
View file

@ -1,8 +1,13 @@
warning: unused imports: `Eq`, `Ord`, `PartialEq`, `PartialOrd`
--> $DIR/multispan-import-lint.rs:11:16
--> $DIR/multispan-import-lint.rs:13:16
|
11 | use std::cmp::{Eq, Ord, min, PartialEq, PartialOrd};
13 | use std::cmp::{Eq, Ord, min, PartialEq, PartialOrd};
| ^^ ^^^ ^^^^^^^^^ ^^^^^^^^^^
|
= note: #[warn(unused_imports)] on by default
note: lint level defined here
--> $DIR/multispan-import-lint.rs:11:9
|
11 | #![warn(unused)]
| ^^^^^^
= note: #[warn(unused_imports)] implied by #[warn(unused)]