From 8a96884981c97c4c35e304004290271308a67637 Mon Sep 17 00:00:00 2001
From: Nilstrieb <48135649+Nilstrieb@users.noreply.github.com>
Date: Tue, 27 Sep 2022 20:56:05 +0200
Subject: [PATCH 1/4] Flush delayed bugs before codegen

Sometimes it can happen that invalid code like a TyKind::Error makes
its way through the compiler without triggering any errors (this is
always a bug in rustc but bugs do happen sometimes :)). These ICEs
will manifest in the backend like as cg_llvm not being able to get
the layout of `[type error]`, which makes it hard to debug. By flushing
before codegen, we display all the delayed bugs, making it easier to
trace it to the root of the problem.
---
 compiler/rustc_errors/src/lib.rs        | 6 ++++++
 compiler/rustc_interface/src/queries.rs | 2 ++
 2 files changed, 8 insertions(+)

diff --git a/compiler/rustc_errors/src/lib.rs b/compiler/rustc_errors/src/lib.rs
index 4d262ae0f5ec8..b4e99225f811f 100644
--- a/compiler/rustc_errors/src/lib.rs
+++ b/compiler/rustc_errors/src/lib.rs
@@ -1133,6 +1133,12 @@ impl Handler {
         );
         std::mem::take(&mut self.inner.borrow_mut().fulfilled_expectations)
     }
+
+    pub fn flush_delayed(&self) {
+        let mut inner = self.inner.lock();
+        let bugs = std::mem::replace(&mut inner.delayed_span_bugs, Vec::new());
+        inner.flush_delayed(bugs, "no errors encountered even though `delay_span_bug` issued");
+    }
 }
 
 impl HandlerInner {
diff --git a/compiler/rustc_interface/src/queries.rs b/compiler/rustc_interface/src/queries.rs
index 6c725a01b5315..60ed48d89886f 100644
--- a/compiler/rustc_interface/src/queries.rs
+++ b/compiler/rustc_interface/src/queries.rs
@@ -246,6 +246,8 @@ impl<'tcx> Queries<'tcx> {
                 // Don't do code generation if there were any errors
                 self.session().compile_status()?;
 
+                self.session().diagnostic().flush_delayed();
+
                 // Hook for UI tests.
                 Self::check_for_rustc_errors_attr(tcx);
 

From 477846f491284973f1f3f8b4bf9c6d9deb6ad98e Mon Sep 17 00:00:00 2001
From: nils <48135649+Nilstrieb@users.noreply.github.com>
Date: Fri, 30 Sep 2022 14:11:18 +0200
Subject: [PATCH 2/4] Add comment explaining why we flush delayed bugs before
 codegen

---
 compiler/rustc_interface/src/queries.rs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/compiler/rustc_interface/src/queries.rs b/compiler/rustc_interface/src/queries.rs
index 60ed48d89886f..05775f376472a 100644
--- a/compiler/rustc_interface/src/queries.rs
+++ b/compiler/rustc_interface/src/queries.rs
@@ -246,6 +246,8 @@ impl<'tcx> Queries<'tcx> {
                 // Don't do code generation if there were any errors
                 self.session().compile_status()?;
 
+                // If we have any delayed bugs, for example beacuse we created TyKind::Error earlier,
+                // it's likey that codegen will only cause more ICEs, obscuring the original problem
                 self.session().diagnostic().flush_delayed();
 
                 // Hook for UI tests.

From 4b1cf846bd39a7409949a394f4c1655f2410c7e6 Mon Sep 17 00:00:00 2001
From: Camille Gillot <gillot.camille@gmail.com>
Date: Fri, 30 Sep 2022 19:50:48 +0200
Subject: [PATCH 3/4] Update compiler/rustc_interface/src/queries.rs

---
 compiler/rustc_interface/src/queries.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compiler/rustc_interface/src/queries.rs b/compiler/rustc_interface/src/queries.rs
index 05775f376472a..6dfaa4453ef3e 100644
--- a/compiler/rustc_interface/src/queries.rs
+++ b/compiler/rustc_interface/src/queries.rs
@@ -246,7 +246,7 @@ impl<'tcx> Queries<'tcx> {
                 // Don't do code generation if there were any errors
                 self.session().compile_status()?;
 
-                // If we have any delayed bugs, for example beacuse we created TyKind::Error earlier,
+                // If we have any delayed bugs, for example because we created TyKind::Error earlier,
                 // it's likey that codegen will only cause more ICEs, obscuring the original problem
                 self.session().diagnostic().flush_delayed();
 

From e8f1bfe1937c51c1a408c98cf810d10ead454314 Mon Sep 17 00:00:00 2001
From: nils <48135649+Nilstrieb@users.noreply.github.com>
Date: Fri, 30 Sep 2022 21:02:53 +0200
Subject: [PATCH 4/4] Fix typo

---
 compiler/rustc_interface/src/queries.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compiler/rustc_interface/src/queries.rs b/compiler/rustc_interface/src/queries.rs
index 6dfaa4453ef3e..91d180e1eb7e5 100644
--- a/compiler/rustc_interface/src/queries.rs
+++ b/compiler/rustc_interface/src/queries.rs
@@ -247,7 +247,7 @@ impl<'tcx> Queries<'tcx> {
                 self.session().compile_status()?;
 
                 // If we have any delayed bugs, for example because we created TyKind::Error earlier,
-                // it's likey that codegen will only cause more ICEs, obscuring the original problem
+                // it's likely that codegen will only cause more ICEs, obscuring the original problem
                 self.session().diagnostic().flush_delayed();
 
                 // Hook for UI tests.