5 files changed, 30 insertions, 22 deletions

diff --git a/crates/ra_project_model/src/cfg_flag.rs b/crates/ra_project_model/src/cfg_flag.rs
index 1bc5d4832..bd50056c6 100644
--- a/crates/ra_project_model/src/cfg_flag.rs
+++ b/crates/ra_project_model/src/cfg_flag.rs
@@ -4,7 +4,7 @@
 use std::str::FromStr;
 
 use ra_cfg::CfgOptions;
-use stdx::split_delim;
+use stdx::split_once;
 
 #[derive(Clone, Eq, PartialEq, Debug)]
 pub enum CfgFlag {
@@ -15,7 +15,7 @@ pub enum CfgFlag {
 impl FromStr for CfgFlag {
     type Err = String;
     fn from_str(s: &str) -> Result<Self, Self::Err> {
-        let res = match split_delim(s, '=') {
+        let res = match split_once(s, '=') {
             Some((key, value)) => {
                 if !(value.starts_with('"') && value.ends_with('"')) {
                     return Err(format!("Invalid cfg ({:?}), value should be in quotes", s));
diff --git a/crates/rust-analyzer/src/cli/analysis_bench.rs b/crates/rust-analyzer/src/cli/analysis_bench.rs
index 076184ad6..13a106638 100644
--- a/crates/rust-analyzer/src/cli/analysis_bench.rs
+++ b/crates/rust-analyzer/src/cli/analysis_bench.rs
@@ -2,7 +2,7 @@
 
 use std::{env, path::Path, str::FromStr, sync::Arc, time::Instant};
 
-use anyhow::{format_err, Result};
+use anyhow::{bail, format_err, Result};
 use ra_db::{
     salsa::{Database, Durability},
     FileId,
@@ -30,19 +30,18 @@ pub struct Position {
 impl FromStr for Position {
     type Err = anyhow::Error;
     fn from_str(s: &str) -> Result<Self> {
-        let (path_line, column) = rsplit_at_char(s, ':')?;
-        let (path, line) = rsplit_at_char(path_line, ':')?;
-        let path = env::current_dir().unwrap().join(path);
-        let path = AbsPathBuf::assert(path);
-        Ok(Position { path, line: line.parse()?, column: column.parse()? })
+        let mut split = s.rsplitn(3, ':');
+        match (split.next(), split.next(), split.next()) {
+            (Some(column), Some(line), Some(path)) => {
+                let path = env::current_dir().unwrap().join(path);
+                let path = AbsPathBuf::assert(path);
+                Ok(Position { path, line: line.parse()?, column: column.parse()? })
+            }
+            _ => bail!("position should be in file:line:column format: {:?}", s),
+        }
     }
 }
 
-fn rsplit_at_char(s: &str, c: char) -> Result<(&str, &str)> {
-    let idx = s.rfind(c).ok_or_else(|| format_err!("no `{}` in {}", c, s))?;
-    Ok((&s[..idx], &s[idx + 1..]))
-}
-
 pub fn analysis_bench(
     verbosity: Verbosity,
     path: &Path,
diff --git a/crates/rust-analyzer/src/handlers.rs b/crates/rust-analyzer/src/handlers.rs
index 62ed6880b..e73b3a211 100644
--- a/crates/rust-analyzer/src/handlers.rs
+++ b/crates/rust-analyzer/src/handlers.rs
@@ -26,7 +26,7 @@ use ra_project_model::TargetKind;
 use ra_syntax::{algo, ast, AstNode, SyntaxKind, TextRange, TextSize};
 use serde::{Deserialize, Serialize};
 use serde_json::to_value;
-use stdx::{format_to, split_delim};
+use stdx::{format_to, split_once};
 
 use crate::{
     cargo_target_spec::CargoTargetSpec,
@@ -865,7 +865,7 @@ pub(crate) fn handle_resolve_code_action(
         .map(|it| it.into_iter().filter_map(from_proto::assist_kind).collect());
 
     let assists = snap.analysis.resolved_assists(&snap.config.assist, frange)?;
-    let (id_string, index) = split_delim(&params.id, ':').unwrap();
+    let (id_string, index) = split_once(&params.id, ':').unwrap();
     let index = index.parse::<usize>().unwrap();
     let assist = &assists[index];
     assert!(assist.assist.id.0 == id_string);
diff --git a/crates/stdx/src/lib.rs b/crates/stdx/src/lib.rs
index ea0e6b949..b65875c96 100644
--- a/crates/stdx/src/lib.rs
+++ b/crates/stdx/src/lib.rs
@@ -109,9 +109,18 @@ pub fn replace(buf: &mut String, from: char, to: &str) {
     *buf = buf.replace(from, to)
 }
 
-pub fn split_delim(haystack: &str, delim: char) -> Option<(&str, &str)> {
-    let idx = haystack.find(delim)?;
-    Some((&haystack[..idx], &haystack[idx + delim.len_utf8()..]))
+// https://github.com/rust-lang/rust/issues/74773
+pub fn split_once(haystack: &str, delim: char) -> Option<(&str, &str)> {
+    let mut split = haystack.splitn(2, delim);
+    let prefix = split.next()?;
+    let suffix = split.next()?;
+    Some((prefix, suffix))
+}
+pub fn rsplit_once(haystack: &str, delim: char) -> Option<(&str, &str)> {
+    let mut split = haystack.rsplitn(2, delim);
+    let suffix = split.next()?;
+    let prefix = split.next()?;
+    Some((prefix, suffix))
 }
 
 pub fn trim_indent(mut text: &str) -> String {
diff --git a/crates/test_utils/src/fixture.rs b/crates/test_utils/src/fixture.rs
index ed764046b..e40b61a94 100644
--- a/crates/test_utils/src/fixture.rs
+++ b/crates/test_utils/src/fixture.rs
@@ -2,7 +2,7 @@
 //! rust-analyzer database from a single string.
 
 use rustc_hash::FxHashMap;
-use stdx::{lines_with_ends, split_delim, trim_indent};
+use stdx::{lines_with_ends, split_once, trim_indent};
 
 #[derive(Debug, Eq, PartialEq)]
 pub struct Fixture {
@@ -71,14 +71,14 @@ impl Fixture {
         let mut cfg_key_values = Vec::new();
         let mut env = FxHashMap::default();
         for component in components[1..].iter() {
-            let (key, value) = split_delim(component, ':').unwrap();
+            let (key, value) = split_once(component, ':').unwrap();
             match key {
                 "crate" => krate = Some(value.to_string()),
                 "deps" => deps = value.split(',').map(|it| it.to_string()).collect(),
                 "edition" => edition = Some(value.to_string()),
                 "cfg" => {
                     for entry in value.split(',') {
-                        match split_delim(entry, '=') {
+                        match split_once(entry, '=') {
                             Some((k, v)) => cfg_key_values.push((k.to_string(), v.to_string())),
                             None => cfg_atoms.push(entry.to_string()),
                         }
@@ -86,7 +86,7 @@ impl Fixture {
                 }
                 "env" => {
                     for key in value.split(',') {
-                        if let Some((k, v)) = split_delim(key, '=') {
+                        if let Some((k, v)) = split_once(key, '=') {
                             env.insert(k.into(), v.into());
                         }
                     }