don't lint allow_attributes on attributes from proc macros

Author: Centri3

clippy_lints/src/allow_attributes.rs

@@ -1,5 +1,5 @@
 use ast::AttrStyle;
-use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::{diagnostics::span_lint_and_sugg, is_from_proc_macro};
 use rustc_ast as ast;
 use rustc_errors::Applicability;
 use rustc_lint::{LateContext, LateLintPass, LintContext};
@@ -57,6 +57,7 @@ impl LateLintPass<'_> for AllowAttribute {
             if let AttrStyle::Outer = attr.style;
             if let Some(ident) = attr.ident();
             if ident.name == rustc_span::symbol::sym::allow;
+            if !is_from_proc_macro(cx, &(attr, cx));
             then {
                 span_lint_and_sugg(
                     cx,

clippy_lints/src/attrs.rs

@@ -1,9 +1,12 @@
 //! checks for attributes
 
-use clippy_utils::diagnostics::{span_lint, span_lint_and_help, span_lint_and_sugg, span_lint_and_then};
 use clippy_utils::macros::{is_panic, macro_backtrace};
 use clippy_utils::msrvs::{self, Msrv};
 use clippy_utils::source::{first_line_of_span, is_present_in_source, snippet_opt, without_block_comments};
+use clippy_utils::{
+    diagnostics::{span_lint, span_lint_and_help, span_lint_and_sugg, span_lint_and_then},
+    is_from_proc_macro,
+};
 use if_chain::if_chain;
 use rustc_ast::{AttrKind, AttrStyle, Attribute, LitKind, MetaItemKind, MetaItemLit, NestedMetaItem};
 use rustc_errors::Applicability;
@@ -540,7 +543,7 @@ fn check_clippy_lint_names(cx: &LateContext<'_>, name: Symbol, items: &[NestedMe
     }
 }
 
-fn check_lint_reason(cx: &LateContext<'_>, name: Symbol, items: &[NestedMetaItem], attr: &'_ Attribute) {
+fn check_lint_reason(cx: &LateContext<'_>, name: Symbol, items: &[NestedMetaItem], attr: &Attribute) {
     // Check for the feature
     if !cx.tcx.features().lint_reasons {
         return;
@@ -555,7 +558,7 @@ fn check_lint_reason(cx: &LateContext<'_>, name: Symbol, items: &[NestedMetaItem
     }
 
     // Check if the attribute is in an external macro and therefore out of the developer's control
-    if in_external_macro(cx.sess(), attr.span) {
+    if in_external_macro(cx.sess(), attr.span) || is_from_proc_macro(cx, &(attr, cx)) {
         return;
     }
 

clippy_utils/src/check_proc_macro.rs

@@ -12,7 +12,11 @@
 //! code was written, and check if the span contains that text. Note this will only work correctly
 //! if the span is not from a `macro_rules` based macro.
 
-use rustc_ast::ast::{IntTy, LitIntType, LitKind, StrStyle, UintTy};
+use rustc_ast::{
+    ast::{AttrKind, Attribute, IntTy, LitIntType, LitKind, StrStyle, UintTy},
+    token::CommentKind,
+    AttrStyle,
+};
 use rustc_hir::{
     intravisit::FnKind, Block, BlockCheckMode, Body, Closure, Destination, Expr, ExprKind, FieldDef, FnHeader, HirId,
     Impl, ImplItem, ImplItemKind, IsAuto, Item, ItemKind, LoopSource, MatchSource, Node, QPath, TraitItem,
@@ -271,6 +275,32 @@ fn fn_kind_pat(tcx: TyCtxt<'_>, kind: &FnKind<'_>, body: &Body<'_>, hir_id: HirI
     (start_pat, end_pat)
 }
 
+fn attr_search_pat(attr: &Attribute) -> (Pat, Pat) {
+    match attr.kind {
+        AttrKind::Normal(..) => {
+            if matches!(attr.style, AttrStyle::Outer) {
+                (Pat::Str("#["), Pat::Str("]"))
+            } else {
+                (Pat::Str("#!["), Pat::Str("]"))
+            }
+        },
+        AttrKind::DocComment(_kind @ CommentKind::Line, ..) => {
+            if matches!(attr.style, AttrStyle::Outer) {
+                (Pat::Str("///"), Pat::Str(""))
+            } else {
+                (Pat::Str("//!"), Pat::Str(""))
+            }
+        },
+        AttrKind::DocComment(_kind @ CommentKind::Block, ..) => {
+            if matches!(attr.style, AttrStyle::Outer) {
+                (Pat::Str("/**"), Pat::Str("*/"))
+            } else {
+                (Pat::Str("/*!"), Pat::Str("*/"))
+            }
+        },
+    }
+}
+
 pub trait WithSearchPat {
     type Context: LintContext;
     fn search_pat(&self, cx: &Self::Context) -> (Pat, Pat);
@@ -310,6 +340,18 @@ impl<'cx> WithSearchPat for (&FnKind<'cx>, &Body<'cx>, HirId, Span) {
     }
 }
 
+impl<'cx> WithSearchPat for (&Attribute, &LateContext<'cx>) {
+    type Context = LateContext<'cx>;
+
+    fn search_pat(&self, _cx: &Self::Context) -> (Pat, Pat) {
+        attr_search_pat(&self.0)
+    }
+
+    fn span(&self) -> Span {
+        self.0.span
+    }
+}
+
 /// Checks if the item likely came from a proc-macro.
 ///
 /// This should be called after `in_external_macro` and the initial pattern matching of the ast as

tests/ui/allow_attributes.fixed

@@ -1,9 +1,12 @@
 //@run-rustfix
+//@aux-build:proc_macros.rs
 #![allow(unused)]
 #![warn(clippy::allow_attributes)]
 #![feature(lint_reasons)]
+#![no_main]
 
-fn main() {}
+extern crate proc_macros;
+use proc_macros::{external, with_span};
 
 // Using clippy::needless_borrow just as a placeholder, it isn't relevant.
 
@@ -17,9 +20,24 @@ struct T3;
 #[warn(clippy::needless_borrow)] // Should not lint
 struct T4;
 // `panic = "unwind"` should always be true
-#[cfg_attr(panic = "unwind", expect(dead_code))]
+#[cfg_attr(panic = "unwind", allow(dead_code))]
 struct CfgT;
 
+fn ignore_external() {
+    external! {
+        #[allow(clippy::needless_borrow)]
+        fn a() {}
+    }
+}
+
+fn ignore_proc_macro() {
+    with_span! {
+        span
+        #[allow(clippy::needless_borrow)] // Should not lint
+        fn a() {}
+    }
+}
+
 fn ignore_inner_attr() {
     #![allow(unused)] // Should not lint
 }

tests/ui/allow_attributes.rs

@@ -1,9 +1,12 @@
 //@run-rustfix
+//@aux-build:proc_macros.rs
 #![allow(unused)]
 #![warn(clippy::allow_attributes)]
 #![feature(lint_reasons)]
+#![no_main]
 
-fn main() {}
+extern crate proc_macros;
+use proc_macros::{external, with_span};
 
 // Using clippy::needless_borrow just as a placeholder, it isn't relevant.
 
@@ -20,6 +23,21 @@ struct T4;
 #[cfg_attr(panic = "unwind", allow(dead_code))]
 struct CfgT;
 
+fn ignore_external() {
+    external! {
+        #[allow(clippy::needless_borrow)] // Should not lint
+        fn a() {}
+    }
+}
+
+fn ignore_proc_macro() {
+    with_span! {
+        span
+        #[allow(clippy::needless_borrow)] // Should not lint
+        fn a() {}
+    }
+}
+
 fn ignore_inner_attr() {
     #![allow(unused)] // Should not lint
 }

tests/ui/allow_attributes.stderr

@@ -1,16 +1,10 @@
 error: #[allow] attribute found
-  --> $DIR/allow_attributes.rs:11:3
+  --> $DIR/allow_attributes.rs:14:3
    |
 LL | #[allow(dead_code)]
    |   ^^^^^ help: replace it with: `expect`
    |
    = note: `-D clippy::allow-attributes` implied by `-D warnings`
 
-error: #[allow] attribute found
-  --> $DIR/allow_attributes.rs:20:30
-   |
-LL | #[cfg_attr(panic = "unwind", allow(dead_code))]
-   |                              ^^^^^ help: replace it with: `expect`
-
-error: aborting due to 2 previous errors
+error: aborting due to previous error
 

tests/ui/allow_attributes_false_positive.rs

@@ -1,14 +1,30 @@
+//@aux-build:proc_macros.rs
 #![feature(lint_reasons)]
 #![deny(clippy::allow_attributes_without_reason)]
+#![allow(unfulfilled_lint_expectations)]
+
+extern crate proc_macros;
+use proc_macros::{external, with_span};
 
 // These should trigger the lint
 #[allow(dead_code)]
 #[allow(dead_code, deprecated)]
+#[expect(dead_code)]
 // These should be fine
 #[allow(dead_code, reason = "This should be allowed")]
 #[warn(dyn_drop, reason = "Warnings can also have reasons")]
 #[warn(deref_nullptr)]
 #[deny(deref_nullptr)]
 #[forbid(deref_nullptr)]
 
-fn main() {}
+fn main() {
+    external! {
+        #[allow(dead_code)]
+        fn a() {}
+    }
+    with_span! {
+        span
+        #[allow(dead_code)]
+        fn b() {}
+    }
+}

tests/ui/allow_attributes_without_reason.rs

@@ -1,23 +1,39 @@
 error: `allow` attribute without specifying a reason
-  --> $DIR/allow_attributes_without_reason.rs:5:1
+  --> $DIR/allow_attributes_without_reason.rs:4:1
    |
-LL | #[allow(dead_code)]
-   | ^^^^^^^^^^^^^^^^^^^
+LL | #![allow(unfulfilled_lint_expectations)]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: try adding a reason at the end with `, reason = ".."`
 note: the lint level is defined here
-  --> $DIR/allow_attributes_without_reason.rs:2:9
+  --> $DIR/allow_attributes_without_reason.rs:3:9
    |
 LL | #![deny(clippy::allow_attributes_without_reason)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: `allow` attribute without specifying a reason
-  --> $DIR/allow_attributes_without_reason.rs:6:1
+  --> $DIR/allow_attributes_without_reason.rs:10:1
+   |
+LL | #[allow(dead_code)]
+   | ^^^^^^^^^^^^^^^^^^^
+   |
+   = help: try adding a reason at the end with `, reason = ".."`
+
+error: `allow` attribute without specifying a reason
+  --> $DIR/allow_attributes_without_reason.rs:11:1
    |
 LL | #[allow(dead_code, deprecated)]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: try adding a reason at the end with `, reason = ".."`
 
-error: aborting due to 2 previous errors
+error: `expect` attribute without specifying a reason
+  --> $DIR/allow_attributes_without_reason.rs:12:1
+   |
+LL | #[expect(dead_code)]
+   | ^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: try adding a reason at the end with `, reason = ".."`
+
+error: aborting due to 4 previous errors