From 5db5d8f87e2d224df6feea200af371d13394f2be Mon Sep 17 00:00:00 2001
From: Matthew Jasper <mjjasper1@gmail.com>
Date: Fri, 15 Jan 2021 20:45:38 +0000
Subject: [PATCH] Make hitting the recursion limit in projection non-fatal
This is relied on by wundergraph.
---
.../src/traits/project.rs | 11 +---
.../src/traits/select/mod.rs | 4 --
.../project-recursion-limit-non-fatal.rs | 58 +++++++++++++++++++
src/test/ui/issues/issue-23122-2.stderr | 3 +-
4 files changed, 63 insertions(+), 13 deletions(-)
create mode 100644 src/test/ui/associated-types/project-recursion-limit-non-fatal.rs
diff --git a/compiler/rustc_trait_selection/src/traits/project.rs b/compiler/rustc_trait_selection/src/traits/project.rs
index fa0526445c1..f22b5b96616 100644
--- a/compiler/rustc_trait_selection/src/traits/project.rs
+++ b/compiler/rustc_trait_selection/src/traits/project.rs
@@ -736,14 +736,9 @@ fn project_type<'cx, 'tcx>(
if !selcx.tcx().sess.recursion_limit().value_within_limit(obligation.recursion_depth) {
debug!("project: overflow!");
- match selcx.query_mode() {
- super::TraitQueryMode::Standard => {
- selcx.infcx().report_overflow_error(&obligation, true);
- }
- super::TraitQueryMode::Canonical => {
- return Err(ProjectionTyError::TraitSelectionError(SelectionError::Overflow));
- }
- }
+ // This should really be an immediate error, but some existing code
+ // relies on being able to recover from this.
+ return Err(ProjectionTyError::TraitSelectionError(SelectionError::Overflow));
}
let obligation_trait_ref = &obligation.predicate.trait_ref(selcx.tcx());
diff --git a/compiler/rustc_trait_selection/src/traits/select/mod.rs b/compiler/rustc_trait_selection/src/traits/select/mod.rs
index 8ca540fc893..7221ce811d1 100644
--- a/compiler/rustc_trait_selection/src/traits/select/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/mod.rs
@@ -291,10 +291,6 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
self.infcx.tcx
}
- pub(super) fn query_mode(&self) -> TraitQueryMode {
- self.query_mode
- }
-
///////////////////////////////////////////////////////////////////////////
// Selection
//
diff --git a/src/test/ui/associated-types/project-recursion-limit-non-fatal.rs b/src/test/ui/associated-types/project-recursion-limit-non-fatal.rs
new file mode 100644
index 00000000000..3e68b140102
--- /dev/null
+++ b/src/test/ui/associated-types/project-recursion-limit-non-fatal.rs
@@ -0,0 +1,58 @@
+// Regression test for #80953. Hitting the recursion limit in projection
+// is non-fatal. The above code, minimised from wundergraph shows a case
+// where this is relied on.
+
+// check-pass
+
+struct AlternateTable {}
+struct AlternateQuery {}
+
+pub trait Query {}
+pub trait AsQuery {
+ type Query;
+}
+impl<T: Query> AsQuery for T {
+ type Query = Self;
+}
+impl AsQuery for AlternateTable {
+ type Query = AlternateQuery;
+}
+
+pub trait Table: AsQuery {
+ type PrimaryKey;
+}
+impl Table for AlternateTable {
+ type PrimaryKey = ();
+}
+
+pub trait FilterDsl<Predicate> {
+ type Output;
+}
+pub type Filter<Source, Predicate> = <Source as FilterDsl<Predicate>>::Output;
+impl<T, Predicate> FilterDsl<Predicate> for T
+where
+ T: Table,
+ T::Query: FilterDsl<Predicate>,
+{
+ type Output = Filter<T::Query, Predicate>;
+}
+impl<Predicate> FilterDsl<Predicate> for AlternateQuery {
+ type Output = &'static str;
+}
+
+pub trait HandleDelete {
+ type Filter;
+}
+impl<T> HandleDelete for T
+where
+ T: Table,
+ T::Query: FilterDsl<T::PrimaryKey>,
+ Filter<T::Query, T::PrimaryKey>: ,
+{
+ type Filter = Filter<T::Query, T::PrimaryKey>;
+}
+
+fn main() {
+ let x: <AlternateTable as HandleDelete>::Filter = "Hello, world";
+ println!("{}", x);
+}
diff --git a/src/test/ui/issues/issue-23122-2.stderr b/src/test/ui/issues/issue-23122-2.stderr
index ff7e884ea6f..ce3bffe602c 100644
--- a/src/test/ui/issues/issue-23122-2.stderr
+++ b/src/test/ui/issues/issue-23122-2.stderr
@@ -1,10 +1,11 @@
-error[E0275]: overflow evaluating the requirement `<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<T as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next`
+error[E0275]: overflow evaluating the requirement `<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<T as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next: Sized`
--> $DIR/issue-23122-2.rs:9:5
|
LL | type Next = <GetNext<T::Next> as Next>::Next;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= help: consider adding a `#![recursion_limit="256"]` attribute to your crate (`issue_23122_2`)
+ = note: required because of the requirements on the impl of `Next` for `GetNext<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<T as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next>`
error: aborting due to previous error