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matthiaskrgrmatthiaskrgr
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Rollup merge of #121560 - Noratrieb:stop-lint-macro-nonsense, r=jieyouxu
Allow `#[deny]` inside `#[forbid]` as a no-op Forbid cannot be overriden. When someome tries to do this anyways, it results in a hard error. That makes sense. Except it doesn't, because macros. Macros may reasonably use `#[deny]` (or `#[warn]` for an allow-by-default lint) in their expansion to assert that their expanded code follows the lint. This is doesn't work when the output gets expanded into a `forbid()` context. This is pretty silly, since both the macros and the code agree on the lint! By making it a warning instead, we remove the problem with the macro, which is now nothing as warnings are suppressed in macro expanded code, while still telling users that something is up. fixes #121483
2 parents bfab34a + 1af9d11 commit 7b714d4

18 files changed

+260
-32
lines changed

‎compiler/rustc_lint/src/levels.rs

Lines changed: 4 additions & 1 deletion
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@@ -493,7 +493,10 @@ impl<'s, P: LintLevelsProvider> LintLevelsBuilder<'s, P> {
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//
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// This means that this only errors if we're truly lowering the lint
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// level from forbid.
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if self.lint_added_lints && level != Level::Forbid && old_level == Level::Forbid {
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if self.lint_added_lints && level == Level::Deny && old_level == Level::Forbid {
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// Having a deny inside a forbid is fine and is ignored, so we skip this check.
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return;
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} else if self.lint_added_lints && level != Level::Forbid && old_level == Level::Forbid {
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// Backwards compatibility check:
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//
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// We used to not consider `forbid(lint_group)`

‎compiler/rustc_lint_defs/src/builtin.rs

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@@ -156,7 +156,7 @@ declare_lint! {
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///
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/// ```rust
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/// #![forbid(warnings)]
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/// #![deny(bad_style)]
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/// #![warn(bad_style)]
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///
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/// fn main() {}
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/// ```

‎src/tools/tidy/src/issues.txt

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@@ -2758,7 +2758,6 @@ ui/lint/issue-63364.rs
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ui/lint/issue-70819-dont-override-forbid-in-same-scope.rs
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ui/lint/issue-79546-fuel-ice.rs
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ui/lint/issue-79744.rs
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ui/lint/issue-80988.rs
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ui/lint/issue-81218.rs
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ui/lint/issue-83477.rs
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ui/lint/issue-87274-paren-parent.rs

‎tests/ui/lint/auxiliary/allow-macro.rs

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@@ -0,0 +1,7 @@
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#[macro_export]
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macro_rules! emit_allow {
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() => {
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#[allow(unsafe_code)]
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let _so_safe = 0;
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};
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}

‎tests/ui/lint/auxiliary/deny-macro.rs

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@@ -0,0 +1,7 @@
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#[macro_export]
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macro_rules! emit_deny {
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() => {
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#[deny(unsafe_code)]
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let _so_safe = 0;
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};
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}

‎tests/ui/lint/auxiliary/forbid-macro.rs

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,7 @@
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#[macro_export]
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macro_rules! emit_forbid {
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() => {
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#[forbid(unsafe_code)]
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let _so_safe = 0;
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};
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}

‎tests/ui/lint/auxiliary/warn-macro.rs

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@@ -0,0 +1,7 @@
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#[macro_export]
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macro_rules! emit_warn {
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() => {
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#[warn(unsafe_code)]
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let _so_safe = 0;
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};
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}

‎tests/ui/lint/deny-inside-forbid-ignored.cli_forbid.stderr

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@@ -0,0 +1,35 @@
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error[E0453]: allow(unsafe_code) incompatible with previous forbid
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--> $DIR/deny-inside-forbid-ignored.rs:12:17
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|
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LL | #[forbid(unsafe_code)] // NO UNSAFE CODE IN HERE!!
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| ----------- `forbid` level set here
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...
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LL | #[allow(unsafe_code)] // let's have some unsafe code in here
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| ^^^^^^^^^^^ overruled by previous forbid
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error[E0453]: allow(unsafe_code) incompatible with previous forbid
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--> $DIR/deny-inside-forbid-ignored.rs:12:17
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|
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LL | #[forbid(unsafe_code)] // NO UNSAFE CODE IN HERE!!
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| ----------- `forbid` level set here
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...
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LL | #[allow(unsafe_code)] // let's have some unsafe code in here
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| ^^^^^^^^^^^ overruled by previous forbid
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|
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= note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
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error: usage of an `unsafe` block
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--> $DIR/deny-inside-forbid-ignored.rs:16:13
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|
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LL | unsafe { /* ≽^•⩊•^≼ */ }
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| ^^^^^^^^^^^^^^^^^^^^^^^^
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|
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note: the lint level is defined here
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--> $DIR/deny-inside-forbid-ignored.rs:8:10
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|
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LL | #[forbid(unsafe_code)] // NO UNSAFE CODE IN HERE!!
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| ^^^^^^^^^^^
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error: aborting due to 3 previous errors
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For more information about this error, try `rustc --explain E0453`.

‎tests/ui/lint/deny-inside-forbid-ignored.cli_forbid_warnings.stderr

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@@ -0,0 +1,35 @@
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error[E0453]: allow(unsafe_code) incompatible with previous forbid
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--> $DIR/deny-inside-forbid-ignored.rs:12:17
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|
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LL | #[forbid(unsafe_code)] // NO UNSAFE CODE IN HERE!!
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| ----------- `forbid` level set here
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...
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LL | #[allow(unsafe_code)] // let's have some unsafe code in here
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| ^^^^^^^^^^^ overruled by previous forbid
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error[E0453]: allow(unsafe_code) incompatible with previous forbid
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--> $DIR/deny-inside-forbid-ignored.rs:12:17
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|
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LL | #[forbid(unsafe_code)] // NO UNSAFE CODE IN HERE!!
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| ----------- `forbid` level set here
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...
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LL | #[allow(unsafe_code)] // let's have some unsafe code in here
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| ^^^^^^^^^^^ overruled by previous forbid
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|
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= note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
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error: usage of an `unsafe` block
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--> $DIR/deny-inside-forbid-ignored.rs:16:13
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|
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LL | unsafe { /* ≽^•⩊•^≼ */ }
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| ^^^^^^^^^^^^^^^^^^^^^^^^
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|
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note: the lint level is defined here
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--> $DIR/deny-inside-forbid-ignored.rs:8:10
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|
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LL | #[forbid(unsafe_code)] // NO UNSAFE CODE IN HERE!!
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| ^^^^^^^^^^^
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error: aborting due to 3 previous errors
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For more information about this error, try `rustc --explain E0453`.

‎tests/ui/lint/deny-inside-forbid-ignored.rs

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@@ -0,0 +1,20 @@
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//! Ensure that using deny inside forbid is treated as a no-op, and does not override the level to
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//! deny.
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//@ revisions: source_only cli_forbid cli_forbid_warnings
5+
//@[cli_forbid] compile-flags: -F unsafe_code
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//@[cli_forbid_warnings] compile-flags: -F warnings
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#[forbid(unsafe_code)] // NO UNSAFE CODE IN HERE!!
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fn main() {
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#[deny(unsafe_code)] // m-m-maybe we can have unsafe code in here?
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{
12+
#[allow(unsafe_code)] // let's have some unsafe code in here
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//~^ ERROR allow(unsafe_code) incompatible with previous forbid
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//~| ERROR allow(unsafe_code) incompatible with previous forbid
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{
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unsafe { /* ≽^•⩊•^≼ */ }
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//~^ ERROR usage of an `unsafe` block
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}
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}
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}

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