3 files changed, 40 insertions, 5 deletions
diff --git a/src/tools/rust-analyzer/crates/stdx/src/lib.rs b/src/tools/rust-analyzer/crates/stdx/src/lib.rs
index 51e109798..5639aaf57 100644
--- a/src/tools/rust-analyzer/crates/stdx/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/stdx/src/lib.rs
@@ -2,15 +2,16 @@
 
 #![warn(rust_2018_idioms, unused_lifetimes, semicolon_in_expressions_from_macros)]
 
+use std::io as sio;
 use std::process::Command;
 use std::{cmp::Ordering, ops, time::Instant};
-use std::{io as sio, iter};
 
 mod macros;
 pub mod hash;
 pub mod process;
 pub mod panic_context;
 pub mod non_empty_vec;
+pub mod rand;
 
 pub use always_assert::{always, never};
 
@@ -39,15 +40,19 @@ Uncomment `default = [ "backtrace" ]` in `crates/stdx/Cargo.toml`.
 }
 
 pub fn to_lower_snake_case(s: &str) -> String {
-    to_snake_case(s, char::to_ascii_lowercase)
+    to_snake_case(s, char::to_lowercase)
 }
 pub fn to_upper_snake_case(s: &str) -> String {
-    to_snake_case(s, char::to_ascii_uppercase)
+    to_snake_case(s, char::to_uppercase)
 }
 
 // Code partially taken from rust/compiler/rustc_lint/src/nonstandard_style.rs
 // commit: 9626f2b
-fn to_snake_case<F: Fn(&char) -> char>(mut s: &str, change_case: F) -> String {
+fn to_snake_case<F, I>(mut s: &str, change_case: F) -> String
+where
+    F: Fn(char) -> I,
+    I: Iterator<Item = char>,
+{
     let mut words = vec![];
 
     // Preserve leading underscores
@@ -75,7 +80,7 @@ fn to_snake_case<F: Fn(&char) -> char>(mut s: &str, change_case: F) -> String {
             }
 
             last_upper = ch.is_uppercase();
-            buf.extend(iter::once(change_case(&ch)));
+            buf.extend(change_case(ch));
         }
 
         words.push(buf);
diff --git a/src/tools/rust-analyzer/crates/stdx/src/macros.rs b/src/tools/rust-analyzer/crates/stdx/src/macros.rs
index d91fc690c..1a9982fa8 100644
--- a/src/tools/rust-analyzer/crates/stdx/src/macros.rs
+++ b/src/tools/rust-analyzer/crates/stdx/src/macros.rs
@@ -43,5 +43,14 @@ macro_rules! impl_from {
                 }
             )*)?
         )*
+    };
+    ($($variant:ident$(<$V:ident>)?),* for $enum:ident) => {
+        $(
+            impl$(<$V>)? From<$variant$(<$V>)?> for $enum$(<$V>)? {
+                fn from(it: $variant$(<$V>)?) -> $enum$(<$V>)? {
+                    $enum::$variant(it)
+                }
+            }
+        )*
     }
 }
diff --git a/src/tools/rust-analyzer/crates/stdx/src/rand.rs b/src/tools/rust-analyzer/crates/stdx/src/rand.rs
new file mode 100644
index 000000000..64aa57eae
--- /dev/null
+++ b/src/tools/rust-analyzer/crates/stdx/src/rand.rs
@@ -0,0 +1,21 @@
+//! We don't use `rand`, as that's too many things for us.
+//!
+//! We currently use oorandom instead, but it's missing these two utilities.
+//! Perhaps we should switch to `fastrand`, or our own small PRNG, it's not like
+//! we need anything more complicated than xor-shift.
+
+pub fn shuffle<T>(slice: &mut [T], mut rand_index: impl FnMut(usize) -> usize) {
+    let mut remaining = slice.len() - 1;
+    while remaining > 0 {
+        let index = rand_index(remaining);
+        slice.swap(remaining, index);
+        remaining -= 1;
+    }
+}
+
+pub fn seed() -> u64 {
+    use std::collections::hash_map::RandomState;
+    use std::hash::{BuildHasher, Hasher};
+
+    RandomState::new().build_hasher().finish()
+}