Use #![no_std] in test crates wherever feasible. (#798) (#799)

In the original code:
```
generate rustdoc JSON:
real    0m20.535s
user    0m17.535s
sys     0m2.646s

cargo test:
real    0m1.223s
user    0m11.498s
sys     0m0.737s

19MB in localdata/test_data
```

With `#![no_std]` where easily feasible:
```
generate rustdoc JSON:
real    0m15.892s
user    0m13.102s
sys     0m2.543s

cargo test:
real    0m1.070s
user    0m10.122s
sys     0m0.791s

8.6MB in localdata/test_data
```

Author: obi1kenobi

src/adapter/tests.rs

@@ -4575,7 +4575,7 @@ fn type_generic_bounds() {
             kind: "Union".into(),
             name: "ExampleUnion".into(),
             generic: "T".into(),
-            bound: "std::fmt::Debug".into(),
+            bound: "core::fmt::Debug".into(),
         },
         Output {
             kind: "Union".into(),

test_crates/associated_consts/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 pub struct Counter(i64);
 
 impl Counter {

test_crates/automatically_derived/src/lib.rs

@@ -1,2 +1,4 @@
+#![no_std]
+
 #[derive(Debug, Clone, PartialOrd, PartialEq, Ord, Eq, Hash)]
 pub struct Example(i64);

test_crates/consts/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 pub const FIRST: u32 = 1;
 
 pub mod inner {

test_crates/cyclic_overlapping_glob_and_local_item/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 // This crate exports:
 // - `Foo` only as itself
 // - `inner::Foo` also as `inner::nested::Foo`, `nested::Foo`, and `nested::inner::Foo`.

test_crates/declarative_macros/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 /// Usable externally as:
 /// ```rust
 /// declarative_macros::top_level!();

test_crates/enum_discriminants/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 #![allow(incomplete_features)]
 #![feature(repr128)]
 /// Some examples from <https://doc.rust-lang.org/reference/items/enumerations.html#implicit-discriminants>

test_crates/enums_are_not_modules/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 pub enum Foo {
     // Enum variants are the exception: they are both visible and importable.
     Variant,

test_crates/explicit_reexport_of_matching_names/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 //! In Rust, type names and value names (including both `fn` and `const`) have different,
 //! mutually-disjoint namespaces. It's allowed for those namespaces to have matching names.
 //! When the name is used, the surrounding context determines whether it's resolved

test_crates/extern_fn/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 extern "C" {
     pub fn legacy_extern_fn();
 }

test_crates/features/src/lib.rs

@@ -0,0 +1,2 @@
+#![no_std]
+

test_crates/function_abi/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 pub extern "C-unwind" fn example_unwind() {}
 
 pub extern "C" fn example_not_unwind() {}

test_crates/function_export_name/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 #[unsafe(no_mangle)]
 pub fn example_not_mangled() {}
 

test_crates/function_export_name_2021/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 #[no_mangle]
 pub fn example_not_mangled() {}
 

test_crates/function_has_body/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 pub fn top_level() {}
 
 pub struct Foo;

test_crates/generic_param_positions/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 #![allow(unused_variables)]
 
 pub fn function<'a, 'b, T, U, const N: usize, const M: usize>(left: &'a [T; N], right: &'b [U; M]) {}
@@ -9,7 +11,7 @@ pub trait Trait<'a, T, const N: usize> {
 pub fn impl_trait<T, U>(first: T, impld: impl Into<U>) -> impl Iterator<Item = T> {}
 
 pub struct Example<'a, 'b> {
-    _marker: std::marker::PhantomData<&'a &'b ()>,
+    _marker: core::marker::PhantomData<&'a &'b ()>,
 }
 
 impl<'a, 'b> Example<'a, 'b> {
@@ -19,7 +21,7 @@ impl<'a, 'b> Example<'a, 'b> {
 }
 
 pub struct SingleLifetimeElided<'a> {
-    _marker: std::marker::PhantomData<&'a ()>,
+    _marker: core::marker::PhantomData<&'a ()>,
 }
 
 impl SingleLifetimeElided<'_> {

test_crates/glob_of_enum_does_not_shadow_local_fn/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 // This crate exports:
 // - `Foo` only as itself.
 // - `inner::First` as itself: it's a function, variants are in the type namespace so no conflict.

test_crates/glob_of_glob_reexport/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 //! This package exports the following:
 //! - `foo`
 //! - `Bar`

test_crates/glob_of_renamed_reexport/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 //! This package exports the following:
 //! - `renamed_foo`
 //! - `RenamedBar`

test_crates/glob_reexport/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 //! This package exports the following:
 //! - `foo`, also as `inner::foo`
 //! - `Bar`, also as `inner::Bar`

test_crates/glob_reexport_cycle/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 //! This package exports the following:
 //! - `first::foo`, also as `second::foo`
 //! - `second::Bar`, also as `first::Bar`

test_crates/glob_reexport_enum_variants/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 //! This package exports the following:
 //! - `First`
 //! - `Second`

test_crates/glob_vs_glob_no_shadowing_for_same_item/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 // There's no shadowing across glob re-exports of the same name
 // if it's the same item both times.
 //

test_crates/glob_vs_glob_no_shadowing_for_same_multiply_renamed_item/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 // There's no shadowing across glob re-exports of the same name
 // if it's the same item both times.
 //

test_crates/glob_vs_glob_no_shadowing_for_same_renamed_item/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 // There's no shadowing across glob re-exports of the same name
 // if it's the same item both times.
 //

test_crates/glob_vs_glob_shadowing/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 // This crate exports only the names `Bar` and `Baz`.
 // While both `Foo` structs are public, their names conflict and are not exported.
 

test_crates/glob_vs_glob_shadowing_downstream/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 // This crate only exports the name `second::Bar`.
 // Inside `first`, the name `Foo` conflicts between the two glob exports.
 //

test_crates/importable_paths/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 pub struct PublicImportable {}
 
 mod private {

test_crates/infinite_corecursive_reexport/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 //! The below function should be available as:
 //! - `a::foo()`
 //! - `b::a::foo()`

test_crates/infinite_indirect_recursive_reexport/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 //! The below function should be available as:
 //! - `foo()`
 //! - `nested::foo()`

test_crates/infinite_recursive_reexport/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 //! The below function should be available as:
 //! - `foo()`
 //! - `inner::foo()`

test_crates/modules/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 pub mod hello {
     pub mod world {
         pub struct T1 {}

test_crates/nested_overlapping_glob_and_local_item/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 // This crate exports:
 // - `Foo` only as itself
 // - `inner::Foo` also as `inner::nested::Foo`, so `inner`'s glob import is a no-op

test_crates/nested_reexport_as_underscore/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 //! This crate does not re-export any *nameable* items.
 //!
 //! However, glob imports of this file (in the style of a prelude)

test_crates/no_shadowing_across_namespaces/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 // Glob imports do not import items whose names would conflict
 // with locally-defined items with those names.
 //

test_crates/non_exhaustive_attribute/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 #[non_exhaustive]
 pub enum NonExhaustiveEnum {
     First,

test_crates/overlapping_glob_and_local_item/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 // This crate exports:
 // - `Foo` only as itself
 // - `inner::Foo` only as itself, meaning that the glob import is a no-op here

test_crates/overlapping_glob_and_local_module/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 // This crate exports:
 // - `sibling::duplicated::Foo` only as itself
 // - `inner::duplicated::Bar` only as itself.

test_crates/overlapping_glob_and_private_import/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 // This crate does not export any names!
 // The only name it could export is `sibling::Foo`, but shadowing prevents it.
 

test_crates/overlapping_glob_and_renamed_module/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 // This crate exports:
 // - `sibling::duplicated::Foo` only as itself
 // - `inner::duplicated::Bar` only as itself.

test_crates/overlapping_glob_of_enum_with_local_item/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 // This crate exports:
 // - `Foo` only as itself
 // - `inner::First` only as itself, overriding the glob import

test_crates/overlapping_reexport_as_underscore/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 //! This crate re-exports only the struct `Example`.
 //!
 //! Even though `second` imports two items named `Example`, one of them is renamed to `_`

test_crates/proc_macros/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 //! Notes on test completeness, as of Rust 1.81:
 //! - Functions annotated with `#[proc_macro]` must be private, or else it's a compile error.
 //! - All proc macros must be defined at the root of the crate, or else it's a compile error.

test_crates/pub_generic_type_alias_added_defaults/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 //! This package exports the following:
 //! - `inner::Foo`
 //! - `inner::Bar`
@@ -10,12 +12,12 @@
 
 pub mod inner {
     pub struct Foo<'a, T, const N: usize> {
-        _marker: std::marker::PhantomData<&'a T>,
+        _marker: core::marker::PhantomData<&'a T>,
         _n: [i64; N],
     }
 
     pub struct Bar<'a, const N: usize, T> {
-        _marker: std::marker::PhantomData<&'a T>,
+        _marker: core::marker::PhantomData<&'a T>,
         _n: [i64; N],
     }
 }

test_crates/pub_generic_type_alias_changed_defaults/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 //! This package does *not* include any re-exports of `inner::Foo` and `inner::Bar`.
 //!
 //! All type aliases change the semantics of the underlying type's generic parameters,
@@ -9,12 +11,12 @@
 
 pub mod inner {
     pub struct Foo<'a, T = i64, const N: usize = 5> {
-        _marker: std::marker::PhantomData<&'a T>,
+        _marker: core::marker::PhantomData<&'a T>,
         _n: [i64; N],
     }
 
     pub struct Bar<'a, const N: usize = 5, T = i64> {
-        _marker: std::marker::PhantomData<&'a T>,
+        _marker: core::marker::PhantomData<&'a T>,
         _n: [i64; N],
     }
 }

test_crates/pub_generic_type_alias_omitted_default/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 //! This package exports the following:
 //! - `inner::DefaultConst`
 //! - `inner::DefaultType`
@@ -14,19 +16,19 @@
 
 pub mod inner {
     pub struct DefaultConst<'a, T, const N: usize = 5> {
-        _marker: std::marker::PhantomData<&'a [T; N]>,
+        _marker: core::marker::PhantomData<&'a [T; N]>,
     }
 
     pub struct DefaultType<'a, const N: usize, T = i64> {
-        _marker: std::marker::PhantomData<&'a [T; N]>,
+        _marker: core::marker::PhantomData<&'a [T; N]>,
     }
 
     pub struct ConstOnly<const N: usize = 5> {
-        _marker: std::marker::PhantomData<[i64; N]>,
+        _marker: core::marker::PhantomData<[i64; N]>,
     }
 
     pub struct TypeOnly<T = i64> {
-        _marker: std::marker::PhantomData<T>,
+        _marker: core::marker::PhantomData<T>,
     }
 }
 

test_crates/pub_generic_type_alias_reexport/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 //! This package exports the following renames of `Foo` (which itself is not directly visible):
 //! - `Exported<'a, T, const N: usize>`
 //! - `ExportedRenamedParams<'b, U, const M: usize>`
@@ -19,7 +21,7 @@
 
 mod inner {
     pub struct Foo<'a, T, const N: usize> {
-        _marker: std::marker::PhantomData<&'a T>,
+        _marker: core::marker::PhantomData<&'a T>,
         _n: [i64; N],
     }
 

test_crates/pub_generic_type_alias_same_signature_but_not_equivalent/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 //! This package exports the following:
 //! - `inner::GenericFoo<A, B>`
 //! - `ChangedFoo<const A: usize, const B: usize>`
@@ -8,7 +10,7 @@
 
 pub mod inner {
     pub struct GenericFoo<A, B> {
-        _marker: std::marker::PhantomData<(A, B)>,
+        _marker: core::marker::PhantomData<(A, B)>,
     }
 }
 

test_crates/pub_generic_type_alias_shuffled_order/src/lib.rs

@@ -1,3 +1,5 @@
+#![no_std]
+
 //! This package exports the following:
 //! - `inner::GenericFoo<A, B>`
 //! - `inner::LifetimeFoo<'a, 'b>`
@@ -13,11 +15,11 @@
 
 pub mod inner {
     pub struct GenericFoo<A, B> {
-        _marker: std::marker::PhantomData<(A, B)>,
+        _marker: core::marker::PhantomData<(A, B)>,
     }
 
     pub struct LifetimeFoo<'a, 'b> {
-        _marker: std::marker::PhantomData<&'a &'b ()>,
+        _marker: core::marker::PhantomData<&'a &'b ()>,
     }
 
     pub struct ConstFoo<const A: usize, const B: usize> {