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