Rollup merge of #141985 - compiler-errors:cycle-in-dep-graph-print, r=oli-obk

Ensure query keys are printed with reduced queries

Using `-Z query-dep-graph` and debug assertions leads to an ICE that was originally discovered in rust-lang/rust#141700:

> This isn't an incremental bug per se, but instead a bug that has to do with debug printing query keys when debug assertions and `-Z query-dep-graph` is enabled. We end up printing a const (b/c we're using generic const args here) whose debug printing for -Z query-dep-graph requires invoking the same query cyclically 😃
>
> I've pushed a commit which should fix this.

This isn't related to the standard library changes, but instead b/c it seems to be the first usage of `feature(adt_const_params)` in the standard library that ends up being triggered in incremental tests.

r? oli-obk

2 files changed, 26 insertions, 1 deletions

diff --git a/tests/incremental/print-dep-node-cycle.rs b/tests/incremental/print-dep-node-cycle.rs
new file mode 100644
index 00000000000..931d3da521e
--- /dev/null
+++ b/tests/incremental/print-dep-node-cycle.rs
@@ -0,0 +1,25 @@
+//@ compile-flags: -Z query-dep-graph
+//@ revisions: rpass1
+
+// Exercises a debug-assertions-only query cycle that when printing a valtree const in
+// a dep node's debug representation, we end up invoking a query that also has a valtree
+// const in its dep node's debug representation, which leads to a cycle (and ICE, since
+// deps are not tracked when printing dep nodes' debug representations).
+
+#![feature(adt_const_params)]
+
+use std::marker::ConstParamTy;
+
+#[derive(Debug, ConstParamTy, PartialEq, Eq)]
+enum Foo {
+    A1,
+}
+
+#[inline(never)]
+fn hello<const F: Foo>() {
+    println!("{:#?}", F);
+}
+
+fn main() {
+    hello::<{ Foo::A1 }>();
+}
diff --git a/tests/ui/transmutability/structs/repr/transmute_infinitely_recursive_type.stderr b/tests/ui/transmutability/structs/repr/transmute_infinitely_recursive_type.stderr
index bdf2d3b6a58..1a0563b469c 100644
--- a/tests/ui/transmutability/structs/repr/transmute_infinitely_recursive_type.stderr
+++ b/tests/ui/transmutability/structs/repr/transmute_infinitely_recursive_type.stderr
@@ -12,7 +12,7 @@ LL |     struct ExplicitlyPadded(Box<ExplicitlyPadded>);
 error[E0391]: cycle detected when computing layout of `should_pad_explicitly_packed_field::ExplicitlyPadded`
    |
    = note: ...which immediately requires computing layout of `should_pad_explicitly_packed_field::ExplicitlyPadded` again
-   = note: cycle used when evaluating trait selection obligation `(): core::mem::transmutability::TransmuteFrom<should_pad_explicitly_packed_field::ExplicitlyPadded, core::mem::transmutability::Assume { alignment: false, lifetimes: false, safety: false, validity: false }>`
+   = note: cycle used when evaluating trait selection obligation `(): core::mem::transmutability::TransmuteFrom<should_pad_explicitly_packed_field::ExplicitlyPadded, ValTree(Branch([Leaf(0x00), Leaf(0x00), Leaf(0x00), Leaf(0x00)]): core::mem::transmutability::Assume)>`
    = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
 
 error: aborting due to 2 previous errors