change category and refactor

Author: Centri3

clippy_lints/src/raw_strings.rs

@@ -13,7 +13,8 @@ declare_clippy_lint! {
     /// Checks for raw string literals where a string literal can be used instead.
     ///
     /// ### Why is this bad?
-    /// It's just unnecessary.
+    /// It's just unnecessary, but there are many cases where using a raw string literal is more
+    /// idiomatic than a string literal, so it's opt-in.
     ///
     /// ### Example
     /// ```rust
@@ -25,7 +26,7 @@ declare_clippy_lint! {
     /// ```
     #[clippy::version = "1.72.0"]
     pub NEEDLESS_RAW_STRING,
-    complexity,
+    restriction,
     "suggests using a string literal when a raw string literal is unnecessary"
 }
 declare_clippy_lint! {
@@ -46,7 +47,7 @@ declare_clippy_lint! {
     /// ```
     #[clippy::version = "1.72.0"]
     pub NEEDLESS_RAW_STRING_HASHES,
-    complexity,
+    style,
     "suggests reducing the number of hashes around a raw string literal"
 }
 impl_lint_pass!(RawStrings => [NEEDLESS_RAW_STRING, NEEDLESS_RAW_STRING_HASHES]);
@@ -59,7 +60,7 @@ impl EarlyLintPass for RawStrings {
     fn check_expr(&mut self, cx: &EarlyContext<'_>, expr: &Expr) {
         if !in_external_macro(cx.sess(), expr.span)
             && let ExprKind::Lit(lit) = expr.kind
-            && let LitKind::StrRaw(num) | LitKind::ByteStrRaw(num) | LitKind::CStrRaw(num) = lit.kind
+            && let LitKind::StrRaw(max) | LitKind::ByteStrRaw(max) | LitKind::CStrRaw(max) = lit.kind
         {
             let prefix = match lit.kind {
                 LitKind::StrRaw(..) => "r",
@@ -86,14 +87,26 @@ impl EarlyLintPass for RawStrings {
             }
 
             #[expect(clippy::cast_possible_truncation)]
-            let req = lit.symbol.as_str().as_bytes()
+            let req = lit
+                .symbol
+                .as_str()
+                .as_bytes()
                 .split(|&b| b == b'"')
                 .skip(1)
-                .map(|bs| 1 + bs.iter().take_while(|&&b| b == b'#').count() as u8)
+                .map_while(|bs| {
+                    let num = bs.iter().take_while(|&&b| b == b'#').count() as u8;
+                    if num.saturating_sub(1) == max {
+                        // Since `num - 1` is the max number of hashes it can have, we can
+                        // short-circuit with full confidence this is correct
+                        return None;
+                    }
+
+                    Some(num + 1)
+                })
                 .max()
                 .unwrap_or(0);
 
-            if req < num {
+            if req < max {
                 let hashes = "#".repeat(req as usize);
 
                 span_lint_and_sugg(

tests/ui/needless_raw_string_hashes.fixed

@@ -1,5 +1,5 @@
 //@run-rustfix
-#![allow(clippy::needless_raw_string, clippy::no_effect, unused)]
+#![allow(clippy::no_effect, unused)]
 #![warn(clippy::needless_raw_string_hashes)]
 #![feature(c_str_literals)]
 

tests/ui/needless_raw_string_hashes.rs

@@ -1,5 +1,5 @@
 //@run-rustfix
-#![allow(clippy::needless_raw_string, clippy::no_effect, unused)]
+#![allow(clippy::no_effect, unused)]
 #![warn(clippy::needless_raw_string_hashes)]
 #![feature(c_str_literals)]