use strip_prefix() instead of starts_with and slicing (clippy::manual_strip)

Author: matthiaskrgr

crates/hir_expand/src/name.rs

@@ -48,9 +48,8 @@ impl Name {
 
     /// Resolve a name from the text of token.
     fn resolve(raw_text: &str) -> Name {
-        let raw_start = "r#";
-        if raw_text.starts_with(raw_start) {
-            Name::new_text(SmolStr::new(&raw_text[raw_start.len()..]))
+        if let Some(text) = raw_text.strip_prefix("r#") {
+            Name::new_text(SmolStr::new(text))
         } else {
             Name::new_text(raw_text.into())
         }

crates/syntax/src/ast/edit.rs

@@ -333,8 +333,7 @@ impl ast::Use {
             .and_then(ast::Whitespace::cast);
         if let Some(next_ws) = next_ws {
             let ws_text = next_ws.syntax().text();
-            if ws_text.starts_with('\n') {
-                let rest = &ws_text[1..];
+            if let Some(rest) = ws_text.strip_prefix('\n') {
                 if rest.is_empty() {
                     res.delete(next_ws.syntax())
                 } else {

xtask/src/codegen/gen_assists_docs.rs

@@ -154,8 +154,8 @@ fn hide_hash_comments(text: &str) -> String {
 fn reveal_hash_comments(text: &str) -> String {
     text.split('\n') // want final newline
         .map(|it| {
-            if it.starts_with("# ") {
-                &it[2..]
+            if let Some(stripped) = it.strip_prefix("# ") {
+                stripped
             } else if it == "#" {
                 ""
             } else {

xtask/src/codegen/gen_parser_tests.rs

@@ -60,12 +60,10 @@ fn collect_tests(s: &str) -> Vec<Test> {
     let mut res = Vec::new();
     for comment_block in extract_comment_blocks(s) {
         let first_line = &comment_block[0];
-        let (name, ok) = if first_line.starts_with("test ") {
-            let name = first_line["test ".len()..].to_string();
-            (name, true)
-        } else if first_line.starts_with("test_err ") {
-            let name = first_line["test_err ".len()..].to_string();
-            (name, false)
+        let (name, ok) = if let Some(name) = first_line.strip_prefix("test ") {
+            (name.to_string(), true)
+        } else if let Some(name) = first_line.strip_prefix("test_err ") {
+            (name.to_string(), false)
         } else {
             continue;
         };