Auto merge of #15618 - shogo-nakano-desu:internal/port-anymap, r=Veykril

internal: port anymap

## Description
- The anymap crate has been ported. During this process, unnecessary features for rust-analyzer have been removed.
- From the tests that were checking the existing licenses, the anymap license (`BlueOak-1.0.0 OR MIT OR Apache-2.0`) has been removed.

## Requests
- While porting the code this time, I have tried to respect the original author's intentions and have kept the comments/codes as much as possible. Please don't hesitate to tell me if you think the comments/codes also need to be appropriately modified.
- If there are any necessary changes regarding the licensing or anything else, please let me know so I can fix them.

## Issue
https://github.com/rust-lang/rust-analyzer/issues/15500

7 files changed, 386 insertions, 14 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 7eac6267b8b..476c0475ce4 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -33,12 +33,6 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9c7d0618f0e0b7e8ff11427422b64564d5fb0be1940354bfe2e0529b18a9d9b8"
 
 [[package]]
-name = "anymap"
-version = "1.0.0-beta.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8f1f8f5a6f3d50d89e3797d7593a50f96bb2aaa20ca0cc7be1fb673232c91d72"
-
-[[package]]
 name = "arbitrary"
 version = "1.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -518,7 +512,6 @@ dependencies = [
 name = "hir-def"
 version = "0.0.0"
 dependencies = [
- "anymap",
  "arrayvec",
  "base-db",
  "bitflags 2.3.2",
diff --git a/Cargo.toml b/Cargo.toml
index ffac946b18f..c382a5a37d2 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -91,9 +91,9 @@ lsp-server = { version = "0.7.4" }
 
 # non-local crates
 smallvec = { version = "1.10.0", features = [
-    "const_new",
-    "union",
-    "const_generics",
+  "const_new",
+  "union",
+  "const_generics",
 ] }
 smol_str = "0.2.0"
 nohash-hasher = "0.2.0"
@@ -103,5 +103,5 @@ serde_json = "1.0.96"
 triomphe = { version = "0.1.8", default-features = false, features = ["std"] }
 # can't upgrade due to dashmap depending on 0.12.3 currently
 hashbrown = { version = "0.12.3", features = [
-    "inline-more",
+  "inline-more",
 ], default-features = false }
diff --git a/crates/hir-def/Cargo.toml b/crates/hir-def/Cargo.toml
index 092aab01120..99b8e9bf0e1 100644
--- a/crates/hir-def/Cargo.toml
+++ b/crates/hir-def/Cargo.toml
@@ -12,7 +12,6 @@ rust-version.workspace = true
 doctest = false
 
 [dependencies]
-anymap = "1.0.0-beta.2"
 arrayvec = "0.7.2"
 bitflags = "2.1.0"
 cov-mark = "2.0.0-pre.1"
@@ -45,6 +44,7 @@ cfg.workspace = true
 tt.workspace = true
 limit.workspace = true
 
+
 [dev-dependencies]
 expect-test = "1.4.0"
 
diff --git a/crates/hir-def/src/dyn_map.rs b/crates/hir-def/src/dyn_map.rs
index 63138aa6ad7..a59bbf7e221 100644
--- a/crates/hir-def/src/dyn_map.rs
+++ b/crates/hir-def/src/dyn_map.rs
@@ -29,8 +29,8 @@ use std::{
     ops::{Index, IndexMut},
 };
 
-use anymap::Map;
 use rustc_hash::FxHashMap;
+use stdx::anymap::Map;
 
 pub struct Key<K, V, P = (K, V)> {
     _phantom: PhantomData<(K, V, P)>,
diff --git a/crates/rust-analyzer/tests/slow-tests/tidy.rs b/crates/rust-analyzer/tests/slow-tests/tidy.rs
index e9b250bebf2..56b5fcef3c2 100644
--- a/crates/rust-analyzer/tests/slow-tests/tidy.rs
+++ b/crates/rust-analyzer/tests/slow-tests/tidy.rs
@@ -157,7 +157,6 @@ Apache-2.0 OR MIT
 Apache-2.0 WITH LLVM-exception OR Apache-2.0 OR MIT
 Apache-2.0/MIT
 BSD-3-Clause
-BlueOak-1.0.0 OR MIT OR Apache-2.0
 CC0-1.0
 ISC
 MIT
diff --git a/crates/stdx/src/anymap.rs b/crates/stdx/src/anymap.rs
new file mode 100644
index 00000000000..fd44e6c6d0f
--- /dev/null
+++ b/crates/stdx/src/anymap.rs
@@ -0,0 +1,379 @@
+//! This file is a port of only the necessary features from https://github.com/chris-morgan/anymap version 1.0.0-beta.2 for use within rust-analyzer.
+//! Copyright © 2014–2022 Chris Morgan. COPYING: https://github.com/chris-morgan/anymap/blob/master/COPYING"
+//! Note that the license is changed from Blue Oak Model 1.0.0 or MIT or Apache-2.0 to MIT OR Apache-2.0
+//!
+//! This implementation provides a safe and convenient store for one value of each type.
+//!
+//! Your starting point is [`Map`]. It has an example.
+//!
+//! # Cargo features
+//!
+//! This implementation has two independent features, each of which provides an implementation providing
+//! types `Map`, `AnyMap`, `OccupiedEntry`, `VacantEntry`, `Entry` and `RawMap`:
+//!
+//! - **std** (default, *enabled* in this build):
+//!   an implementation using `std::collections::hash_map`, placed in the crate root
+//!   (e.g. `anymap::AnyMap`).
+
+#![warn(missing_docs, unused_results)]
+
+use core::convert::TryInto;
+use core::hash::Hasher;
+
+/// A hasher designed to eke a little more speed out, given `TypeId`’s known characteristics.
+///
+/// Specifically, this is a no-op hasher that expects to be fed a u64’s worth of
+/// randomly-distributed bits. It works well for `TypeId` (eliminating start-up time, so that my
+/// get_missing benchmark is ~30ns rather than ~900ns, and being a good deal faster after that, so
+/// that my insert_and_get_on_260_types benchmark is ~12μs instead of ~21.5μs), but will
+/// panic in debug mode and always emit zeros in release mode for any other sorts of inputs, so
+/// yeah, don’t use it! 😀
+#[derive(Default)]
+pub struct TypeIdHasher {
+    value: u64,
+}
+
+impl Hasher for TypeIdHasher {
+    #[inline]
+    fn write(&mut self, bytes: &[u8]) {
+        // This expects to receive exactly one 64-bit value, and there’s no realistic chance of
+        // that changing, but I don’t want to depend on something that isn’t expressly part of the
+        // contract for safety. But I’m OK with release builds putting everything in one bucket
+        // if it *did* change (and debug builds panicking).
+        debug_assert_eq!(bytes.len(), 8);
+        let _ = bytes.try_into().map(|array| self.value = u64::from_ne_bytes(array));
+    }
+
+    #[inline]
+    fn finish(&self) -> u64 {
+        self.value
+    }
+}
+
+use core::any::{Any, TypeId};
+use core::hash::BuildHasherDefault;
+use core::marker::PhantomData;
+
+use ::std::collections::hash_map::{self, HashMap};
+
+/// Raw access to the underlying `HashMap`.
+///
+/// This alias is provided for convenience because of the ugly third generic parameter.
+pub type RawMap<A> = HashMap<TypeId, Box<A>, BuildHasherDefault<TypeIdHasher>>;
+
+/// A collection containing zero or one values for any given type and allowing convenient,
+/// type-safe access to those values.
+///
+/// The type parameter `A` allows you to use a different value type; normally you will want
+/// it to be `core::any::Any` (also known as `std::any::Any`), but there are other choices:
+///
+/// - If you want the entire map to be cloneable, use `CloneAny` instead of `Any`; with
+///   that, you can only add types that implement `Clone` to the map.
+/// - You can add on `+ Send` or `+ Send + Sync` (e.g. `Map<dyn Any + Send>`) to add those
+///   auto traits.
+///
+/// Cumulatively, there are thus six forms of map:
+///
+/// - <code>[Map]&lt;dyn [core::any::Any]&gt;</code>,
+///   also spelled [`AnyMap`] for convenience.
+/// - <code>[Map]&lt;dyn [core::any::Any] + Send&gt;</code>
+/// - <code>[Map]&lt;dyn [core::any::Any] + Send + Sync&gt;</code>
+/// - <code>[Map]&lt;dyn [CloneAny]&gt;</code>
+/// - <code>[Map]&lt;dyn [CloneAny] + Send&gt;</code>
+/// - <code>[Map]&lt;dyn [CloneAny] + Send + Sync&gt;</code>
+///
+/// ## Example
+///
+/// (Here using the [`AnyMap`] convenience alias; the first line could use
+/// <code>[anymap::Map][Map]::&lt;[core::any::Any]&gt;::new()</code> instead if desired.)
+///
+/// ```rust
+#[doc = "let mut data = anymap::AnyMap::new();"]
+/// assert_eq!(data.get(), None::<&i32>);
+/// ```
+///
+/// Values containing non-static references are not permitted.
+#[derive(Debug)]
+pub struct Map<A: ?Sized + Downcast = dyn Any> {
+    raw: RawMap<A>,
+}
+
+/// The most common type of `Map`: just using `Any`; <code>[Map]&lt;dyn [Any]&gt;</code>.
+///
+/// Why is this a separate type alias rather than a default value for `Map<A>`?
+/// `Map::new()` doesn’t seem to be happy to infer that it should go with the default
+/// value. It’s a bit sad, really. Ah well, I guess this approach will do.
+pub type AnyMap = Map<dyn Any>;
+impl<A: ?Sized + Downcast> Default for Map<A> {
+    #[inline]
+    fn default() -> Map<A> {
+        Map::new()
+    }
+}
+
+impl<A: ?Sized + Downcast> Map<A> {
+    /// Create an empty collection.
+    #[inline]
+    pub fn new() -> Map<A> {
+        Map { raw: RawMap::with_hasher(Default::default()) }
+    }
+
+    /// Returns a reference to the value stored in the collection for the type `T`,
+    /// if it exists.
+    #[inline]
+    pub fn get<T: IntoBox<A>>(&self) -> Option<&T> {
+        self.raw.get(&TypeId::of::<T>()).map(|any| unsafe { any.downcast_ref_unchecked::<T>() })
+    }
+
+    /// Gets the entry for the given type in the collection for in-place manipulation
+    #[inline]
+    pub fn entry<T: IntoBox<A>>(&mut self) -> Entry<'_, A, T> {
+        match self.raw.entry(TypeId::of::<T>()) {
+            hash_map::Entry::Occupied(e) => {
+                Entry::Occupied(OccupiedEntry { inner: e, type_: PhantomData })
+            }
+            hash_map::Entry::Vacant(e) => {
+                Entry::Vacant(VacantEntry { inner: e, type_: PhantomData })
+            }
+        }
+    }
+}
+
+/// A view into a single occupied location in an `Map`.
+pub struct OccupiedEntry<'a, A: ?Sized + Downcast, V: 'a> {
+    inner: hash_map::OccupiedEntry<'a, TypeId, Box<A>>,
+    type_: PhantomData<V>,
+}
+
+/// A view into a single empty location in an `Map`.
+pub struct VacantEntry<'a, A: ?Sized + Downcast, V: 'a> {
+    inner: hash_map::VacantEntry<'a, TypeId, Box<A>>,
+    type_: PhantomData<V>,
+}
+
+/// A view into a single location in an `Map`, which may be vacant or occupied.
+pub enum Entry<'a, A: ?Sized + Downcast, V> {
+    /// An occupied Entry
+    Occupied(OccupiedEntry<'a, A, V>),
+    /// A vacant Entry
+    Vacant(VacantEntry<'a, A, V>),
+}
+
+impl<'a, A: ?Sized + Downcast, V: IntoBox<A>> Entry<'a, A, V> {
+    /// Ensures a value is in the entry by inserting the result of the default function if
+    /// empty, and returns a mutable reference to the value in the entry.
+    #[inline]
+    pub fn or_insert_with<F: FnOnce() -> V>(self, default: F) -> &'a mut V {
+        match self {
+            Entry::Occupied(inner) => inner.into_mut(),
+            Entry::Vacant(inner) => inner.insert(default()),
+        }
+    }
+}
+
+impl<'a, A: ?Sized + Downcast, V: IntoBox<A>> OccupiedEntry<'a, A, V> {
+    /// Converts the OccupiedEntry into a mutable reference to the value in the entry
+    /// with a lifetime bound to the collection itself
+    #[inline]
+    pub fn into_mut(self) -> &'a mut V {
+        unsafe { self.inner.into_mut().downcast_mut_unchecked() }
+    }
+}
+
+impl<'a, A: ?Sized + Downcast, V: IntoBox<A>> VacantEntry<'a, A, V> {
+    /// Sets the value of the entry with the VacantEntry's key,
+    /// and returns a mutable reference to it
+    #[inline]
+    pub fn insert(self, value: V) -> &'a mut V {
+        unsafe { self.inner.insert(value.into_box()).downcast_mut_unchecked() }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[derive(Clone, Debug, PartialEq)]
+    struct A(i32);
+    #[derive(Clone, Debug, PartialEq)]
+    struct B(i32);
+    #[derive(Clone, Debug, PartialEq)]
+    struct C(i32);
+    #[derive(Clone, Debug, PartialEq)]
+    struct D(i32);
+    #[derive(Clone, Debug, PartialEq)]
+    struct E(i32);
+    #[derive(Clone, Debug, PartialEq)]
+    struct F(i32);
+    #[derive(Clone, Debug, PartialEq)]
+    struct J(i32);
+
+    #[test]
+    fn test_varieties() {
+        fn assert_send<T: Send>() {}
+        fn assert_sync<T: Sync>() {}
+        fn assert_debug<T: ::core::fmt::Debug>() {}
+        assert_send::<Map<dyn Any + Send>>();
+        assert_send::<Map<dyn Any + Send + Sync>>();
+        assert_sync::<Map<dyn Any + Send + Sync>>();
+        assert_debug::<Map<dyn Any>>();
+        assert_debug::<Map<dyn Any + Send>>();
+        assert_debug::<Map<dyn Any + Send + Sync>>();
+        assert_send::<Map<dyn CloneAny + Send>>();
+        assert_send::<Map<dyn CloneAny + Send + Sync>>();
+        assert_sync::<Map<dyn CloneAny + Send + Sync>>();
+        assert_debug::<Map<dyn CloneAny>>();
+        assert_debug::<Map<dyn CloneAny + Send>>();
+        assert_debug::<Map<dyn CloneAny + Send + Sync>>();
+    }
+
+    #[test]
+    fn type_id_hasher() {
+        use core::any::TypeId;
+        use core::hash::Hash;
+        fn verify_hashing_with(type_id: TypeId) {
+            let mut hasher = TypeIdHasher::default();
+            type_id.hash(&mut hasher);
+            // SAFETY: u64 is valid for all bit patterns.
+            let _ = hasher.finish();
+        }
+        // Pick a variety of types, just to demonstrate it’s all sane. Normal, zero-sized, unsized, &c.
+        verify_hashing_with(TypeId::of::<usize>());
+        verify_hashing_with(TypeId::of::<()>());
+        verify_hashing_with(TypeId::of::<str>());
+        verify_hashing_with(TypeId::of::<&str>());
+        verify_hashing_with(TypeId::of::<Vec<u8>>());
+    }
+}
+
+// impl some traits for dyn Any
+use core::fmt;
+
+#[doc(hidden)]
+pub trait CloneToAny {
+    /// Clone `self` into a new `Box<dyn CloneAny>` object.
+    fn clone_to_any(&self) -> Box<dyn CloneAny>;
+}
+
+impl<T: Any + Clone> CloneToAny for T {
+    #[inline]
+    fn clone_to_any(&self) -> Box<dyn CloneAny> {
+        Box::new(self.clone())
+    }
+}
+
+macro_rules! impl_clone {
+    ($t:ty) => {
+        impl Clone for Box<$t> {
+            #[inline]
+            fn clone(&self) -> Box<$t> {
+                // SAFETY: this dance is to reapply any Send/Sync marker. I’m not happy about this
+                // approach, given that I used to do it in safe code, but then came a dodgy
+                // future-compatibility warning where_clauses_object_safety, which is spurious for
+                // auto traits but still super annoying (future-compatibility lints seem to mean
+                // your bin crate needs a corresponding allow!). Although I explained my plight¹
+                // and it was all explained and agreed upon, no action has been taken. So I finally
+                // caved and worked around it by doing it this way, which matches what’s done for
+                // core::any², so it’s probably not *too* bad.
+                //
+                // ¹ https://github.com/rust-lang/rust/issues/51443#issuecomment-421988013
+                // ² https://github.com/rust-lang/rust/blob/e7825f2b690c9a0d21b6f6d84c404bb53b151b38/library/alloc/src/boxed.rs#L1613-L1616
+                let clone: Box<dyn CloneAny> = (**self).clone_to_any();
+                let raw: *mut dyn CloneAny = Box::into_raw(clone);
+                unsafe { Box::from_raw(raw as *mut $t) }
+            }
+        }
+
+        impl fmt::Debug for $t {
+            #[inline]
+            fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+                f.pad(stringify!($t))
+            }
+        }
+    };
+}
+
+/// Methods for downcasting from an `Any`-like trait object.
+///
+/// This should only be implemented on trait objects for subtraits of `Any`, though you can
+/// implement it for other types and it’ll work fine, so long as your implementation is correct.
+pub trait Downcast {
+    /// Gets the `TypeId` of `self`.
+    fn type_id(&self) -> TypeId;
+
+    // Note the bound through these downcast methods is 'static, rather than the inexpressible
+    // concept of Self-but-as-a-trait (where Self is `dyn Trait`). This is sufficient, exceeding
+    // TypeId’s requirements. Sure, you *can* do CloneAny.downcast_unchecked::<NotClone>() and the
+    // type system won’t protect you, but that doesn’t introduce any unsafety: the method is
+    // already unsafe because you can specify the wrong type, and if this were exposing safe
+    // downcasting, CloneAny.downcast::<NotClone>() would just return an error, which is just as
+    // correct.
+    //
+    // Now in theory we could also add T: ?Sized, but that doesn’t play nicely with the common
+    // implementation, so I’m doing without it.
+
+    /// Downcast from `&Any` to `&T`, without checking the type matches.
+    ///
+    /// # Safety
+    ///
+    /// The caller must ensure that `T` matches the trait object, on pain of *undefined behaviour*.
+    unsafe fn downcast_ref_unchecked<T: 'static>(&self) -> &T;
+
+    /// Downcast from `&mut Any` to `&mut T`, without checking the type matches.
+    ///
+    /// # Safety
+    ///
+    /// The caller must ensure that `T` matches the trait object, on pain of *undefined behaviour*.
+    unsafe fn downcast_mut_unchecked<T: 'static>(&mut self) -> &mut T;
+}
+
+/// A trait for the conversion of an object into a boxed trait object.
+pub trait IntoBox<A: ?Sized + Downcast>: Any {
+    /// Convert self into the appropriate boxed form.
+    fn into_box(self) -> Box<A>;
+}
+
+macro_rules! implement {
+    ($any_trait:ident $(+ $auto_traits:ident)*) => {
+        impl Downcast for dyn $any_trait $(+ $auto_traits)* {
+            #[inline]
+            fn type_id(&self) -> TypeId {
+                self.type_id()
+            }
+
+            #[inline]
+            unsafe fn downcast_ref_unchecked<T: 'static>(&self) -> &T {
+                &*(self as *const Self as *const T)
+            }
+
+            #[inline]
+            unsafe fn downcast_mut_unchecked<T: 'static>(&mut self) -> &mut T {
+                &mut *(self as *mut Self as *mut T)
+            }
+        }
+
+        impl<T: $any_trait $(+ $auto_traits)*> IntoBox<dyn $any_trait $(+ $auto_traits)*> for T {
+            #[inline]
+            fn into_box(self) -> Box<dyn $any_trait $(+ $auto_traits)*> {
+                Box::new(self)
+            }
+        }
+    }
+}
+
+implement!(Any);
+implement!(Any + Send);
+implement!(Any + Send + Sync);
+
+/// [`Any`], but with cloning.
+///
+/// Every type with no non-`'static` references that implements `Clone` implements `CloneAny`.
+/// See [`core::any`] for more details on `Any` in general.
+pub trait CloneAny: Any + CloneToAny {}
+impl<T: Any + Clone> CloneAny for T {}
+implement!(CloneAny);
+implement!(CloneAny + Send);
+implement!(CloneAny + Send + Sync);
+impl_clone!(dyn CloneAny);
+impl_clone!(dyn CloneAny + Send);
+impl_clone!(dyn CloneAny + Send + Sync);
diff --git a/crates/stdx/src/lib.rs b/crates/stdx/src/lib.rs
index 89c54eee55f..f26c7f6dfc2 100644
--- a/crates/stdx/src/lib.rs
+++ b/crates/stdx/src/lib.rs
@@ -12,6 +12,7 @@ pub mod panic_context;
 pub mod non_empty_vec;
 pub mod rand;
 pub mod thread;
+pub mod anymap;
 
 pub use always_assert::{always, never};