Auto merge of #140695 - Zalathar:rollup-i32gzbo, r=Zalathar

Rollup of 12 pull requests

Successful merges:

 - #139550 (Fix `-Zremap-path-scope` rmeta handling)
 - #139764 (Consistent trait bounds for ExtractIf Debug impls)
 - #139773 (Implement `Iterator::last` for `vec::IntoIter`)
 - #140035 (Implement RFC 3503: frontmatters)
 - #140251 (coverage-dump: Resolve global file IDs to filenames)
 - #140393 (std: get rid of `sys_common::process`)
 - #140532 (Fix RustAnalyzer discovery of rustc's `stable_mir` crate)
 - #140598 (Steer docs to `utf8_chunks` and `Iterator::take`)
 - #140634 (Use more accurate ELF flags on MIPS)
 - #140673 (Clean rustdoc tests folder)
 - #140678 (Be a bit more relaxed about not yet constrained infer vars in closure upvar analysis)
 - #140687 (Update mdbook to 0.4.49)

r? `@ghost`
`@rustbot` modify labels: rollup

1 files changed, 91 insertions, 0 deletions

diff --git a/tests/rustdoc/constant/hide-complex-unevaluated-const-arguments.rs b/tests/rustdoc/constant/hide-complex-unevaluated-const-arguments.rs
new file mode 100644
index 00000000000..e94c1ea5c61
--- /dev/null
+++ b/tests/rustdoc/constant/hide-complex-unevaluated-const-arguments.rs
@@ -0,0 +1,91 @@
+// Test that certain unevaluated constant expression arguments that are
+// deemed too verbose or complex and that may leak private or
+// `doc(hidden)` struct fields are not displayed in the documentation.
+//
+// Read the documentation of `rustdoc::clean::utils::print_const_expr`
+// for further details.
+#![feature(const_trait_impl, generic_const_exprs, adt_const_params, generic_const_items)]
+#![allow(incomplete_features)]
+
+use std::marker::ConstParamTy;
+
+//@ has hide_complex_unevaluated_const_arguments/trait.Stage.html
+pub trait Stage {
+    // A helper constant that prevents const expressions containing it
+    // from getting fully evaluated since it doesn't have a body and
+    // thus is non-reducible. This allows us to specifically test the
+    // pretty-printing of *unevaluated* consts.
+    const ABSTRACT: usize;
+
+    // Currently considered "overly complex" by the `generic_const_exprs`
+    // feature. If / once this expression kind gets supported, this
+    // unevaluated const expression could leak the private struct field.
+    //
+    // FIXME: Once the line below compiles, make this a test that
+    //        ensures that the private field is not printed.
+    //
+    //const ARRAY0: [u8; Struct { private: () } + Self::ABSTRACT];
+
+    // This assoc. const could leak the private assoc. function `Struct::new`.
+    // Ensure that this does not happen.
+    //
+    //@ has - '//*[@id="associatedconstant.ARRAY1"]' \
+    //        'const ARRAY1: [u8; { _ }]'
+    const ARRAY1: [u8; Struct::new(/* ... */).do_something(Self::ABSTRACT * 1_000)]
+        where [(); Struct::new(/* ... */).do_something(Self::ABSTRACT * 1_000)]:;
+
+    //@ has - '//*[@id="associatedconstant.VERBOSE"]' \
+    //        'const VERBOSE: [u16; { _ }]'
+    const VERBOSE: [u16; compute("thing", 9 + 9) * Self::ABSTRACT]
+        where [(); compute("thing", 9 + 9) * Self::ABSTRACT]:;
+
+    // Check that we do not leak the private struct field contained within
+    // the path. The output could definitely be improved upon
+    // (e.g. printing sth. akin to `<Self as Helper<{ _ }>>::OUT`) but
+    // right now “safe is safe”.
+    //
+    //@ has - '//*[@id="associatedconstant.PATH"]' \
+    //        'const PATH: usize = _'
+    const PATH: usize = <Self as Helper<{ Struct { private: () } }>>::OUT;
+}
+
+const fn compute(input: &str, extra: usize) -> usize {
+    input.len() + extra
+}
+
+pub trait Helper<const S: Struct> {
+    const OUT: usize;
+}
+
+impl<const S: Struct, St: Stage + ?Sized> Helper<S> for St {
+    const OUT: usize = St::ABSTRACT;
+}
+
+// Currently in rustdoc, const arguments are not evaluated in this position
+// and therefore they fall under the realm of `print_const_expr`.
+// If rustdoc gets patched to evaluate const arguments, it is fine to replace
+// this test as long as one can ensure that private fields are not leaked!
+//
+//@ has hide_complex_unevaluated_const_arguments/trait.Sub.html \
+//      '//pre[@class="rust item-decl"]' \
+//      'pub trait Sub: Sup<{ _ }, { _ }> { }'
+pub trait Sub: Sup<{ 90 * 20 * 4 }, { Struct { private: () } }> {}
+
+pub trait Sup<const N: usize, const S: Struct> {}
+
+#[derive(ConstParamTy, PartialEq, Eq)]
+pub struct Struct { private: () }
+
+impl Struct {
+    const fn new() -> Self { Self { private: () } }
+    const fn do_something(self, x: usize) -> usize {
+        x
+    }
+}
+/* FIXME(const-trait): readd this
+impl const std::ops::Add<usize> for Struct {
+    type Output = usize;
+
+    fn add(self, _: usize) -> usize { 0 }
+}
+*/