Remove the deprecated E999 rule code

crates/ruff/tests/integration_test.rs

@@ -859,27 +859,6 @@ fn parse_error_not_included() {
     ");
 }
 
-#[test]
-fn deprecated_parse_error_selection() {
-    let mut cmd = RuffCheck::default().args(["--select=E999"]).build();
-    assert_cmd_snapshot!(cmd
-        .pass_stdin("foo =\n"), @r"
-    success: false
-    exit_code: 1
-    ----- stdout -----
-    -:1:6: SyntaxError: Expected an expression
-      |
-    1 | foo =
-      |      ^
-      |
-
-    Found 1 error.
-
-    ----- stderr -----
-    warning: Rule `E999` is deprecated and will be removed in a future release. Syntax errors will always be shown regardless of whether this rule is selected or not.
-    ");
-}
-
 #[test]
 fn full_output_preview() {
     let mut cmd = RuffCheck::default().args(["--preview"]).build();

crates/ruff/tests/snapshots/show_settings__display_default_settings.snap

@@ -88,7 +88,6 @@ linter.rules.enabled = [
 	ambiguous-class-name (E742),
 	ambiguous-function-name (E743),
 	io-error (E902),
-	syntax-error (E999),
 	unused-import (F401),
 	import-shadowed-by-loop-var (F402),
 	undefined-local-with-import-star (F403),
@@ -150,7 +149,6 @@ linter.rules.should_fix = [
 	ambiguous-class-name (E742),
 	ambiguous-function-name (E743),
 	io-error (E902),
-	syntax-error (E999),
 	unused-import (F401),
 	import-shadowed-by-loop-var (F402),
 	undefined-local-with-import-star (F403),

crates/ruff_linter/src/codes.rs

@@ -126,7 +126,6 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<(RuleGroup, Rule)> {
         (Pycodestyle, "E742") => (RuleGroup::Stable, rules::pycodestyle::rules::AmbiguousClassName),
         (Pycodestyle, "E743") => (RuleGroup::Stable, rules::pycodestyle::rules::AmbiguousFunctionName),
         (Pycodestyle, "E902") => (RuleGroup::Stable, rules::pycodestyle::rules::IOError),
-        (Pycodestyle, "E999") => (RuleGroup::Deprecated, rules::pycodestyle::rules::SyntaxError),
 
         // pycodestyle warnings
         (Pycodestyle, "W191") => (RuleGroup::Stable, rules::pycodestyle::rules::TabIndentation),

crates/ruff_linter/src/rules/pycodestyle/rules/errors.rs

@@ -38,39 +38,3 @@ impl Violation for IOError {
         format!("{message}")
     }
 }
-
-/// ## Deprecated
-/// This rule has been deprecated and will be removed in a future release. Syntax errors will
-/// always be shown regardless of whether this rule is selected or not.
-///
-/// ## What it does
-/// Checks for code that contains syntax errors.
-///
-/// ## Why is this bad?
-/// Code with syntax errors cannot be executed. Such errors are likely a
-/// mistake.
-///
-/// ## Example
-/// ```python
-/// x =
-/// ```
-///
-/// Use instead:
-/// ```python
-/// x = 1
-/// ```
-///
-/// ## References
-/// - [Python documentation: Syntax Errors](https://docs.python.org/3/tutorial/errors.html#syntax-errors)
-#[violation]
-pub struct SyntaxError {
-    pub message: String,
-}
-
-impl Violation for SyntaxError {
-    #[derive_message_formats]
-    fn message(&self) -> String {
-        let SyntaxError { message } = self;
-        format!("SyntaxError: {message}")
-    }
-}

crates/ruff_linter/src/rules/pycodestyle/rules/mod.rs

@@ -6,7 +6,6 @@ pub(crate) use blank_lines::*;
 pub(crate) use compound_statements::*;
 pub(crate) use doc_line_too_long::*;
 pub use errors::IOError;
-pub(crate) use errors::*;
 pub(crate) use invalid_escape_sequence::*;
 pub(crate) use lambda_assignment::*;
 pub(crate) use line_too_long::*;

crates/ruff_workspace/src/configuration.rs

@@ -1613,7 +1613,6 @@ mod tests {
             Rule::AmbiguousClassName,
             Rule::AmbiguousFunctionName,
             Rule::IOError,
-            Rule::SyntaxError,
             Rule::TabIndentation,
             Rule::TrailingWhitespace,
             Rule::MissingNewlineAtEndOfFile,