From b72996e3220d4a32f1d2bd40c3e0b8ae5d87d351 Mon Sep 17 00:00:00 2001
From: "Christopher B. Speir" <chris@cbspeir.dev>
Date: Tue, 20 Feb 2024 20:07:54 -0600
Subject: [PATCH] Add check for 'in_external_macro' and 'is_from_proc_macro'
 inside [infinite_loop] lint.

---
 clippy_lints/src/loops/infinite_loop.rs | 11 +++++---
 tests/ui/infinite_loops.rs              | 27 ++++++++++++++++++++
 tests/ui/infinite_loops.stderr          | 34 ++++++++++++-------------
 3 files changed, 52 insertions(+), 20 deletions(-)

diff --git a/clippy_lints/src/loops/infinite_loop.rs b/clippy_lints/src/loops/infinite_loop.rs
index 5e099f1e7..5b5bb88c1 100644
--- a/clippy_lints/src/loops/infinite_loop.rs
+++ b/clippy_lints/src/loops/infinite_loop.rs
@@ -1,17 +1,18 @@
 use clippy_utils::diagnostics::span_lint_and_then;
-use clippy_utils::{fn_def_id, is_lint_allowed};
+use clippy_utils::{fn_def_id, is_from_proc_macro, is_lint_allowed};
 use hir::intravisit::{walk_expr, Visitor};
 use hir::{Expr, ExprKind, FnRetTy, FnSig, Node};
 use rustc_ast::Label;
 use rustc_errors::Applicability;
 use rustc_hir as hir;
-use rustc_lint::LateContext;
+use rustc_lint::{LateContext, LintContext};
+use rustc_middle::lint::in_external_macro;
 
 use super::INFINITE_LOOP;
 
 pub(super) fn check<'tcx>(
     cx: &LateContext<'tcx>,
-    expr: &Expr<'_>,
+    expr: &Expr<'tcx>,
     loop_block: &'tcx hir::Block<'_>,
     label: Option<Label>,
 ) {
@@ -34,6 +35,10 @@ pub(super) fn check<'tcx>(
         return;
     }
 
+    if in_external_macro(cx.sess(), expr.span) || is_from_proc_macro(cx, expr) {
+        return;
+    }
+
     let mut loop_visitor = LoopVisitor {
         cx,
         label,
diff --git a/tests/ui/infinite_loops.rs b/tests/ui/infinite_loops.rs
index 646f1eca5..52fbbaa8e 100644
--- a/tests/ui/infinite_loops.rs
+++ b/tests/ui/infinite_loops.rs
@@ -1,7 +1,12 @@
 //@no-rustfix
+//@aux-build:proc_macros.rs
+
 #![allow(clippy::never_loop)]
 #![warn(clippy::infinite_loop)]
 
+extern crate proc_macros;
+use proc_macros::{external, with_span};
+
 fn do_something() {}
 
 fn no_break() {
@@ -363,4 +368,26 @@ fn inf_loop_in_res() -> Result<(), i32> {
     })
 }
 
+with_span! { span
+    fn no_loop() {}
+}
+
+with_span! { span
+    fn with_loop() {
+        loop {
+            do_nothing();
+        }
+    }
+}
+
+fn do_nothing() {}
+
+fn span_inside_fn() {
+    with_span! { span
+        loop {
+            do_nothing();
+        }
+    }
+}
+
 fn main() {}
diff --git a/tests/ui/infinite_loops.stderr b/tests/ui/infinite_loops.stderr
index 012696f38..ec6bd81dc 100644
--- a/tests/ui/infinite_loops.stderr
+++ b/tests/ui/infinite_loops.stderr
@@ -1,5 +1,5 @@
 error: infinite loop detected
-  --> tests/ui/infinite_loops.rs:8:5
+  --> tests/ui/infinite_loops.rs:13:5
    |
 LL | /     loop {
 LL | |
@@ -15,7 +15,7 @@ LL | fn no_break() -> ! {
    |               ++++
 
 error: infinite loop detected
-  --> tests/ui/infinite_loops.rs:15:5
+  --> tests/ui/infinite_loops.rs:20:5
    |
 LL | /     loop {
 LL | |
@@ -32,7 +32,7 @@ LL | fn all_inf() -> ! {
    |              ++++
 
 error: infinite loop detected
-  --> tests/ui/infinite_loops.rs:17:9
+  --> tests/ui/infinite_loops.rs:22:9
    |
 LL | /         loop {
 LL | |
@@ -49,7 +49,7 @@ LL | fn all_inf() -> ! {
    |              ++++
 
 error: infinite loop detected
-  --> tests/ui/infinite_loops.rs:19:13
+  --> tests/ui/infinite_loops.rs:24:13
    |
 LL | /             loop {
 LL | |
@@ -63,7 +63,7 @@ LL | fn all_inf() -> ! {
    |              ++++
 
 error: infinite loop detected
-  --> tests/ui/infinite_loops.rs:33:5
+  --> tests/ui/infinite_loops.rs:38:5
    |
 LL | /     loop {
 LL | |
@@ -74,7 +74,7 @@ LL | |     }
    = help: if this is not intended, try adding a `break` or `return` condition in the loop
 
 error: infinite loop detected
-  --> tests/ui/infinite_loops.rs:46:5
+  --> tests/ui/infinite_loops.rs:51:5
    |
 LL | /     loop {
 LL | |         fn inner_fn() -> ! {
@@ -90,7 +90,7 @@ LL | fn no_break_never_ret_noise() -> ! {
    |                               ++++
 
 error: infinite loop detected
-  --> tests/ui/infinite_loops.rs:89:5
+  --> tests/ui/infinite_loops.rs:94:5
    |
 LL | /     loop {
 LL | |
@@ -107,7 +107,7 @@ LL | fn break_inner_but_not_outer_1(cond: bool) -> ! {
    |                                            ++++
 
 error: infinite loop detected
-  --> tests/ui/infinite_loops.rs:100:5
+  --> tests/ui/infinite_loops.rs:105:5
    |
 LL | /     loop {
 LL | |
@@ -124,7 +124,7 @@ LL | fn break_inner_but_not_outer_2(cond: bool) -> ! {
    |                                            ++++
 
 error: infinite loop detected
-  --> tests/ui/infinite_loops.rs:114:9
+  --> tests/ui/infinite_loops.rs:119:9
    |
 LL | /         loop {
 LL | |
@@ -138,7 +138,7 @@ LL | fn break_outer_but_not_inner() -> ! {
    |                                ++++
 
 error: infinite loop detected
-  --> tests/ui/infinite_loops.rs:137:9
+  --> tests/ui/infinite_loops.rs:142:9
    |
 LL | /         loop {
 LL | |
@@ -155,7 +155,7 @@ LL | fn break_wrong_loop(cond: bool) -> ! {
    |                                 ++++
 
 error: infinite loop detected
-  --> tests/ui/infinite_loops.rs:177:5
+  --> tests/ui/infinite_loops.rs:182:5
    |
 LL | /     loop {
 LL | |
@@ -172,7 +172,7 @@ LL | fn match_like() -> ! {
    |                 ++++
 
 error: infinite loop detected
-  --> tests/ui/infinite_loops.rs:218:5
+  --> tests/ui/infinite_loops.rs:223:5
    |
 LL | /     loop {
 LL | |
@@ -186,7 +186,7 @@ LL | fn match_like() -> ! {
    |                 ++++
 
 error: infinite loop detected
-  --> tests/ui/infinite_loops.rs:223:5
+  --> tests/ui/infinite_loops.rs:228:5
    |
 LL | /     loop {
 LL | |
@@ -203,7 +203,7 @@ LL | fn match_like() -> ! {
    |                 ++++
 
 error: infinite loop detected
-  --> tests/ui/infinite_loops.rs:328:9
+  --> tests/ui/infinite_loops.rs:333:9
    |
 LL | /         loop {
 LL | |
@@ -217,7 +217,7 @@ LL |     fn problematic_trait_method() -> ! {
    |                                   ++++
 
 error: infinite loop detected
-  --> tests/ui/infinite_loops.rs:338:9
+  --> tests/ui/infinite_loops.rs:343:9
    |
 LL | /         loop {
 LL | |
@@ -231,7 +231,7 @@ LL |     fn could_be_problematic() -> ! {
    |                               ++++
 
 error: infinite loop detected
-  --> tests/ui/infinite_loops.rs:347:9
+  --> tests/ui/infinite_loops.rs:352:9
    |
 LL | /         loop {
 LL | |
@@ -245,7 +245,7 @@ LL |     let _loop_forever = || -> ! {
    |                            ++++
 
 error: infinite loop detected
-  --> tests/ui/infinite_loops.rs:361:8
+  --> tests/ui/infinite_loops.rs:366:8
    |
 LL |       Ok(loop {
    |  ________^