[WIP] feat(linter): add eslint/no-unused-vars

crates/oxc_ast/src/ast/js.rs

@@ -1282,6 +1282,33 @@ impl<'a> BindingPatternKind<'a> {
     pub fn is_binding_identifier(&self) -> bool {
         matches!(self, Self::BindingIdentifier(_))
     }
+
+    /// Get the [`BindingIdentifier`] for this pattern if it is not a destructuring pattern.
+    pub fn identifier(&self) -> Option<&Box<'_, BindingIdentifier>> {
+        match self {
+            BindingPatternKind::BindingIdentifier(id) => Some(id),
+            BindingPatternKind::AssignmentPattern(pat) => pat.left.kind.identifier(),
+            _ => None,
+        }
+    }
+
+    pub fn has_binding_for(&self, name: &Atom) -> bool {
+        match self {
+            Self::BindingIdentifier(id) => id.name == name,
+            Self::AssignmentPattern(id) => id.left.kind.has_binding_for(name),
+            Self::ObjectPattern(pat) => {
+                pat.rest.as_ref().is_some_and(|rest| rest.argument.kind.has_binding_for(name))
+                    || pat.properties.iter().any(|p| p.value.kind.has_binding_for(name))
+            }
+            Self::ArrayPattern(pat) => {
+                pat.rest.as_ref().is_some_and(|rest| rest.argument.kind.has_binding_for(name))
+                    || pat
+                        .elements
+                        .iter()
+                        .any(|el| el.as_ref().is_some_and(|el| el.kind.has_binding_for(name)))
+            }
+        }
+    }
 }
 
 #[derive(Debug, Hash)]
@@ -1750,6 +1777,17 @@ pub enum ImportDeclarationSpecifier {
     /// import * as local from "source"
     ImportNamespaceSpecifier(ImportNamespaceSpecifier),
 }
+impl ImportDeclarationSpecifier {
+    /// Get the identifier for this import that is referrable by other nodes
+    /// within the scope the import occurred
+    pub fn local(&self) -> &BindingIdentifier {
+        match self {
+            Self::ImportSpecifier(import) => &import.local,
+            Self::ImportDefaultSpecifier(import) => &import.local,
+            Self::ImportNamespaceSpecifier(import) => &import.local,
+        }
+    }
+}
 
 // import {imported} from "source"
 // import {imported as local} from "source"

crates/oxc_linter/Cargo.toml

@@ -22,6 +22,7 @@ oxc_semantic    = { workspace = true }
 oxc_syntax      = { workspace = true }
 oxc_formatter   = { workspace = true }
 
+bitflags    = { workspace = true } 
 lazy_static = { workspace = true }                        # used in oxc_macros
 serde_json  = { workspace = true }
 regex       = { workspace = true }

crates/oxc_linter/src/rules.rs

@@ -146,6 +146,7 @@ oxc_macros::declare_all_lint_rules! {
     eslint::no_unsafe_negation,
     eslint::no_unsafe_optional_chaining,
     eslint::no_unused_labels,
+    eslint::no_unused_vars,
     eslint::no_useless_catch,
     eslint::no_useless_escape,
     eslint::require_yield,