convert to Rule "directly" from NoqaCode

it's not exactly direct because we're still matching on a bunch of &'static
strs, but it's better than having to call Rule::from_code, which has to format a
string and then reparse the NoqaCode into pieces

Author: ntBre

crates/ruff_linter/src/message/mod.rs

@@ -285,7 +285,7 @@ impl OldDiagnostic {
     /// Returns the [`Rule`] corresponding to the diagnostic message.
     pub fn to_rule(&self) -> Option<Rule> {
         self.noqa_code
-            .map(|code| Rule::from_code(&code.to_string()).expect("Expected a valid noqa code"))
+            .map(|code| code.rule().expect("Expected a valid noqa code"))
     }
 
     /// Returns the [`NoqaCode`] corresponding to the diagnostic message.

crates/ruff_linter/src/registry.rs

@@ -214,12 +214,6 @@ pub enum Linter {
 }
 
 pub trait RuleNamespace: Sized {
-    /// Returns the prefix that every single code that ruff uses to identify
-    /// rules from this linter starts with.  In the case that multiple
-    /// `#[prefix]`es are configured for the variant in the `Linter` enum
-    /// definition this is the empty string.
-    fn common_prefix(&self) -> &'static str;
-
     /// Attempts to parse the given rule code. If the prefix is recognized
     /// returns the respective variant along with the code with the common
     /// prefix stripped.

crates/ruff_linter/src/rule_selector.rs

@@ -265,7 +265,6 @@ mod schema {
     use strum::IntoEnumIterator;
 
     use crate::RuleSelector;
-    use crate::registry::RuleNamespace;
     use crate::rule_selector::{Linter, RuleCodePrefix};
 
     impl JsonSchema for RuleSelector {

crates/ruff_macros/src/map_codes.rs

@@ -254,9 +254,11 @@ fn generate_rule_to_code(linter_to_rules: &BTreeMap<Ident, BTreeMap<String, Rule
     }
 
     let mut rule_noqa_code_match_arms = quote!();
+    let mut noqa_code_rule_match_arms = quote!();
     let mut rule_group_match_arms = quote!();
+    let mut noqa_code_consts = quote!();
 
-    for (rule, codes) in rule_to_codes {
+    for (i, (rule, codes)) in rule_to_codes.into_iter().enumerate() {
         let rule_name = rule.segments.last().unwrap();
         assert_eq!(
             codes.len(),
@@ -292,6 +294,14 @@ See also https://github.com/astral-sh/ruff/issues/2186.
             #(#attrs)* Rule::#rule_name => NoqaCode(crate::registry::Linter::#linter.common_prefix(), #code),
         });
 
+        let const_ident = quote::format_ident!("NOQA_PREFIX_{}", i);
+        noqa_code_consts.extend(quote! {
+            const #const_ident: &str = crate::registry::Linter::#linter.common_prefix();
+        });
+        noqa_code_rule_match_arms.extend(quote! {
+            #(#attrs)* NoqaCode(#const_ident, #code) => Some(Rule::#rule_name),
+        });
+
         rule_group_match_arms.extend(quote! {
             #(#attrs)* Rule::#rule_name => #group,
         });
@@ -340,6 +350,16 @@ See also https://github.com/astral-sh/ruff/issues/2186.
                 }
             }
         }
+
+        impl NoqaCode {
+            pub fn rule(&self) -> Option<Rule> {
+                #noqa_code_consts
+                match self {
+                    #noqa_code_rule_match_arms
+                    _ => None
+                }
+            }
+        }
     };
     rule_to_code
 }

crates/ruff_macros/src/rule_namespace.rs

@@ -118,10 +118,6 @@ pub(crate) fn derive_impl(input: DeriveInput) -> syn::Result<proc_macro2::TokenS
                 None
             }
 
-            fn common_prefix(&self) -> &'static str {
-                match self { #common_prefix_match_arms }
-            }
-
             fn name(&self) -> &'static str {
                 match self { #name_match_arms }
             }
@@ -130,6 +126,16 @@ pub(crate) fn derive_impl(input: DeriveInput) -> syn::Result<proc_macro2::TokenS
                 match self { #url_match_arms }
             }
         }
+
+        impl #ident {
+            /// Returns the prefix that every single code that ruff uses to identify
+            /// rules from this linter starts with.  In the case that multiple
+            /// `#[prefix]`es are configured for the variant in the `Linter` enum
+            /// definition this is the empty string.
+            pub const fn common_prefix(&self) -> &'static str {
+                match self { #common_prefix_match_arms }
+            }
+        }
     })
 }
 

crates/ruff_workspace/src/configuration.rs

@@ -22,7 +22,6 @@ use ruff_cache::cache_dir;
 use ruff_formatter::IndentStyle;
 use ruff_graph::{AnalyzeSettings, Direction};
 use ruff_linter::line_width::{IndentWidth, LineLength};
-use ruff_linter::registry::RuleNamespace;
 use ruff_linter::registry::{INCOMPATIBLE_CODES, Rule, RuleSet};
 use ruff_linter::rule_selector::{PreviewOptions, Specificity};
 use ruff_linter::rules::{flake8_import_conventions, isort, pycodestyle};