From 2cd117ba810d4e239bcc0ee1c95a646a668dd180 Mon Sep 17 00:00:00 2001
From: Charlie Marsh <charlie.r.marsh@gmail.com>
Date: Sun, 16 Jul 2023 21:24:16 -0400
Subject: [PATCH] Remove `TryIdentifier` trait (#5816)

## Summary

Last remaining usage here is for patterns, but we now have ranges on
identifiers so it's unnecessary.
---
 crates/ruff/src/checkers/ast/mod.rs      |  4 +-
 crates/ruff_python_ast/src/identifier.rs | 59 +-----------------------
 2 files changed, 3 insertions(+), 60 deletions(-)

diff --git a/crates/ruff/src/checkers/ast/mod.rs b/crates/ruff/src/checkers/ast/mod.rs
index 14966f63f7..a974ff14ec 100644
--- a/crates/ruff/src/checkers/ast/mod.rs
+++ b/crates/ruff/src/checkers/ast/mod.rs
@@ -12,7 +12,7 @@ use rustpython_parser::ast::{
 use ruff_diagnostics::{Diagnostic, Fix, IsolationLevel};
 use ruff_python_ast::all::{extract_all_names, AllNamesFlags};
 use ruff_python_ast::helpers::{extract_handled_exceptions, to_module_path};
-use ruff_python_ast::identifier::{Identifier, TryIdentifier};
+use ruff_python_ast::identifier::Identifier;
 use ruff_python_ast::source_code::{Generator, Indexer, Locator, Quote, Stylist};
 use ruff_python_ast::str::trailing_quote;
 use ruff_python_ast::types::Node;
@@ -4085,7 +4085,7 @@ where
         {
             self.add_binding(
                 name,
-                pattern.try_identifier().unwrap(),
+                name.range(),
                 BindingKind::Assignment,
                 BindingFlags::empty(),
             );
diff --git a/crates/ruff_python_ast/src/identifier.rs b/crates/ruff_python_ast/src/identifier.rs
index 9e38119515..dabbffccbb 100644
--- a/crates/ruff_python_ast/src/identifier.rs
+++ b/crates/ruff_python_ast/src/identifier.rs
@@ -11,7 +11,7 @@
 //! This module can be used to identify the [`TextRange`] of the `except` token.
 
 use ruff_text_size::{TextLen, TextRange, TextSize};
-use rustpython_ast::{Alias, Arg, ArgWithDefault, Pattern};
+use rustpython_ast::{Alias, Arg, ArgWithDefault};
 use rustpython_parser::ast::{self, ExceptHandler, Ranged, Stmt};
 
 use ruff_python_whitespace::{is_python_whitespace, Cursor};
@@ -23,12 +23,6 @@ pub trait Identifier {
     fn identifier(&self) -> TextRange;
 }
 
-pub trait TryIdentifier {
-    /// Return the [`TextRange`] of the identifier in the given AST node, or `None` if
-    /// the node does not have an identifier.
-    fn try_identifier(&self) -> Option<TextRange>;
-}
-
 impl Identifier for Stmt {
     /// Return the [`TextRange`] of the identifier in the given statement.
     ///
@@ -87,57 +81,6 @@ impl Identifier for Alias {
     }
 }
 
-impl TryIdentifier for Pattern {
-    /// Return the [`TextRange`] of the identifier in the given pattern.
-    ///
-    /// For example, return the range of `z` in:
-    /// ```python
-    /// match x:
-    ///     # Pattern::MatchAs
-    ///     case z:
-    ///         ...
-    /// ```
-    ///
-    /// Or:
-    /// ```python
-    /// match x:
-    ///     # Pattern::MatchAs
-    ///     case y as z:
-    ///         ...
-    /// ```
-    ///
-    /// Or :
-    /// ```python
-    /// match x:
-    ///     # Pattern::MatchMapping
-    ///     case {"a": 1, **z}
-    ///         ...
-    /// ```
-    ///
-    /// Or :
-    /// ```python
-    /// match x:
-    ///     # Pattern::MatchStar
-    ///     case *z:
-    ///         ...
-    /// ```
-    fn try_identifier(&self) -> Option<TextRange> {
-        let name = match self {
-            Pattern::MatchAs(ast::PatternMatchAs {
-                name: Some(name), ..
-            }) => Some(name),
-            Pattern::MatchMapping(ast::PatternMatchMapping {
-                rest: Some(rest), ..
-            }) => Some(rest),
-            Pattern::MatchStar(ast::PatternMatchStar {
-                name: Some(name), ..
-            }) => Some(name),
-            _ => None,
-        };
-        name.map(Ranged::range)
-    }
-}
-
 /// Return the [`TextRange`] of the `except` token in an [`ExceptHandler`].
 pub fn except(handler: &ExceptHandler, locator: &Locator) -> TextRange {
     IdentifierTokenizer::new(locator.contents(), handler.range())