From a28a78f247a0f02521e97eabf98e790085a4a753 Mon Sep 17 00:00:00 2001
From: Fabian Wolff <fabian.wolff@alumni.ethz.ch>
Date: Sun, 3 Oct 2021 21:04:36 +0200
Subject: [PATCH] Fix ICE with buffered lint referring to AST node deleted by
 everybody_loops

---
 compiler/rustc_interface/src/passes.rs | 18 ++++++++++++------
 src/test/ui/lint/issue-87308.rs        | 12 ++++++++++++
 src/test/ui/lint/issue-87308.stdout    | 14 ++++++++++++++
 3 files changed, 38 insertions(+), 6 deletions(-)
 create mode 100644 src/test/ui/lint/issue-87308.rs
 create mode 100644 src/test/ui/lint/issue-87308.stdout

diff --git a/compiler/rustc_interface/src/passes.rs b/compiler/rustc_interface/src/passes.rs
index a221746f975ed..2d12ea94a0bbf 100644
--- a/compiler/rustc_interface/src/passes.rs
+++ b/compiler/rustc_interface/src/passes.rs
@@ -437,12 +437,18 @@ pub fn configure_and_expand(
     });
 
     // Add all buffered lints from the `ParseSess` to the `Session`.
-    sess.parse_sess.buffered_lints.with_lock(|buffered_lints| {
-        info!("{} parse sess buffered_lints", buffered_lints.len());
-        for early_lint in buffered_lints.drain(..) {
-            resolver.lint_buffer().add_early_lint(early_lint);
-        }
-    });
+    // The ReplaceBodyWithLoop pass may have deleted some AST nodes, potentially
+    // causing a delay_span_bug later if a buffered lint refers to such a deleted
+    // AST node (issue #87308). Since everybody_loops is for pretty-printing only,
+    // anyway, we simply skip all buffered lints here.
+    if !matches!(sess.opts.pretty, Some(PpMode::Source(PpSourceMode::EveryBodyLoops))) {
+        sess.parse_sess.buffered_lints.with_lock(|buffered_lints| {
+            info!("{} parse sess buffered_lints", buffered_lints.len());
+            for early_lint in buffered_lints.drain(..) {
+                resolver.lint_buffer().add_early_lint(early_lint);
+            }
+        });
+    }
 
     Ok(krate)
 }
diff --git a/src/test/ui/lint/issue-87308.rs b/src/test/ui/lint/issue-87308.rs
new file mode 100644
index 0000000000000..48fbb2a0139f0
--- /dev/null
+++ b/src/test/ui/lint/issue-87308.rs
@@ -0,0 +1,12 @@
+// Regression test for issue #87308.
+
+// compile-flags: -Zunpretty=everybody_loops
+// check-pass
+
+macro_rules! foo {
+    () => { break 'x; }
+}
+
+pub fn main() {
+    'x: loop { foo!() }
+}
diff --git a/src/test/ui/lint/issue-87308.stdout b/src/test/ui/lint/issue-87308.stdout
new file mode 100644
index 0000000000000..68a076c93be61
--- /dev/null
+++ b/src/test/ui/lint/issue-87308.stdout
@@ -0,0 +1,14 @@
+#![feature(prelude_import)]
+#![no_std]
+#[prelude_import]
+use ::std::prelude::rust_2015::*;
+#[macro_use]
+extern crate std;
+// Regression test for issue #87308.
+
+// compile-flags: -Zunpretty=everybody_loops
+// check-pass
+
+macro_rules! foo { () => { break 'x ; } }
+
+pub fn main() { loop { } }