fix(linter/unicorn): handle type casts and parens in no-null (#5175)

crates/oxc_linter/src/ast_util.rs

@@ -2,7 +2,7 @@ use std::hash::{Hash, Hasher};
 
 use oxc_ast::ast::BindingIdentifier;
 use oxc_ast::AstKind;
-use oxc_semantic::{AstNode, SymbolId};
+use oxc_semantic::{AstNode, AstNodeId, SymbolId};
 use oxc_span::{GetSpan, Span};
 use oxc_syntax::operator::{AssignmentOperator, BinaryOperator, LogicalOperator, UnaryOperator};
 use rustc_hash::FxHasher;
@@ -251,6 +251,24 @@ pub fn nth_outermost_paren_parent<'a, 'b>(
         .filter(|parent| !matches!(parent.kind(), AstKind::ParenthesizedExpression(_)))
         .nth(n)
 }
+/// Iterate over parents of `node`, skipping nodes that are also ignored by
+/// [`Expression::get_inner_expression`].
+pub fn iter_outer_expressions<'a, 'ctx>(
+    ctx: &'ctx LintContext<'a>,
+    node_id: AstNodeId,
+) -> impl Iterator<Item = &'ctx AstNode<'a>> + 'ctx {
+    ctx.nodes().iter_parents(node_id).skip(1).filter(|parent| {
+        !matches!(
+            parent.kind(),
+            AstKind::ParenthesizedExpression(_)
+                | AstKind::TSAsExpression(_)
+                | AstKind::TSSatisfiesExpression(_)
+                | AstKind::TSInstantiationExpression(_)
+                | AstKind::TSNonNullExpression(_)
+                | AstKind::TSTypeAssertion(_)
+        )
+    })
+}
 
 pub fn get_declaration_of_variable<'a, 'b>(
     ident: &IdentifierReference,

crates/oxc_linter/src/rules/unicorn/no_null.rs

@@ -11,7 +11,7 @@ use oxc_syntax::operator::BinaryOperator;
 use serde_json::Value;
 
 use crate::{
-    ast_util::is_method_call,
+    ast_util::{is_method_call, iter_outer_expressions},
     context::LintContext,
     fixer::{RuleFix, RuleFixer},
     rule::Rule,
@@ -53,13 +53,15 @@ declare_oxc_lint!(
 );
 
 fn match_null_arg(call_expr: &CallExpression, index: usize, span: Span) -> bool {
-    call_expr.arguments.get(index).map_or(false, |arg| {
-        if let Argument::NullLiteral(null_lit) = arg {
-            return null_lit.span == span;
-        }
-
-        false
-    })
+    match call_expr
+        .arguments
+        .get(index)
+        .and_then(Argument::as_expression)
+        .map(Expression::get_inner_expression)
+    {
+        Some(Expression::NullLiteral(null_lit)) => span.contains_inclusive(null_lit.span),
+        _ => false,
+    }
 }
 
 impl NoNull {
@@ -173,52 +175,45 @@ impl Rule for NoNull {
             return;
         };
 
-        if let Some(parent_node) = ctx.nodes().parent_node(node.id()) {
-            let grand_parent_kind = ctx.nodes().parent_kind(parent_node.id());
+        let mut parents = iter_outer_expressions(ctx, node.id());
+        let Some(parent_kind) = parents.next().map(AstNode::kind) else {
+            ctx.diagnostic_with_fix(no_null_diagnostic(null_literal.span), |fixer| {
+                fix_null(fixer, null_literal)
+            });
+            return;
+        };
 
-            if matches!(parent_node.kind(), AstKind::Argument(_)) {
-                if let Some(AstKind::CallExpression(call_expr)) = grand_parent_kind {
-                    if match_call_expression_pass_case(null_literal, call_expr) {
-                        return;
-                    }
-                }
+        let grandparent_kind = parents.next().map(AstNode::kind);
+        match (parent_kind, grandparent_kind) {
+            (AstKind::Argument(_), Some(AstKind::CallExpression(call_expr)))
+                if match_call_expression_pass_case(null_literal, call_expr) =>
+            {
+                // no violation
             }
-
-            if let AstKind::BinaryExpression(binary_expr) = parent_node.kind() {
+            (AstKind::BinaryExpression(binary_expr), _) => {
                 self.diagnose_binary_expression(ctx, null_literal, binary_expr);
-                return;
             }
-
-            if let AstKind::VariableDeclarator(variable_declarator) = parent_node.kind() {
-                diagnose_variable_declarator(
-                    ctx,
-                    null_literal,
-                    variable_declarator,
-                    grand_parent_kind,
-                );
-
-                return;
+            (AstKind::VariableDeclarator(decl), _) => {
+                diagnose_variable_declarator(ctx, null_literal, decl, grandparent_kind);
             }
-
-            // `function foo() { return null; }`,
-            if matches!(parent_node.kind(), AstKind::ReturnStatement(_)) {
+            (AstKind::ReturnStatement(_), _) => {
                 ctx.diagnostic_with_fix(no_null_diagnostic(null_literal.span), |fixer| {
-                    fixer.delete_range(null_literal.span)
+                    fixer.delete(null_literal)
+                });
+            }
+            _ => {
+                ctx.diagnostic_with_fix(no_null_diagnostic(null_literal.span), |fixer| {
+                    fix_null(fixer, null_literal)
                 });
-
-                return;
             }
         }
-
-        ctx.diagnostic_with_fix(no_null_diagnostic(null_literal.span), |fixer| {
-            fix_null(fixer, null_literal)
-        });
     }
 }
 
 fn fix_null<'a>(fixer: RuleFixer<'_, 'a>, null: &NullLiteral) -> RuleFix<'a> {
     fixer.replace(null.span, "undefined")
 }
+
 #[test]
 fn test() {
     use crate::tester::Tester;
@@ -232,6 +227,7 @@ fn test() {
     let pass = vec![
         ("let foo", None),
         ("Object.create(null)", None),
+        ("Object.create(null as any)", None),
         ("Object.create(null, {foo: {value:1}})", None),
         ("let insertedNode = parentNode.insertBefore(newNode, null)", None),
         ("const foo = \"null\";", None),
@@ -239,6 +235,8 @@ fn test() {
         ("Object.create(bar)", None),
         ("Object.create(\"null\")", None),
         ("useRef(null)", None),
+        ("useRef(((((null)))))", None),
+        ("useRef(null as unknown as HTMLElement)", None),
         ("React.useRef(null)", None),
         ("if (foo === null) {}", None),
         ("if (null === foo) {}", None),
@@ -301,6 +299,7 @@ fn test() {
         ("Object.create(...[null])", None),
         ("Object.create(null, bar, extraArgument)", None),
         ("foo.insertBefore(null)", None),
+        ("foo.insertBefore(null as any)", None),
         ("foo.insertBefore(foo, null, bar)", None),
         ("foo.insertBefore(...[foo], null)", None),
         // Not in right position

crates/oxc_linter/src/snapshots/no_null.snap

@@ -235,6 +235,13 @@ source: crates/oxc_linter/src/tester.rs
    ╰────
   help: Replace `null` with `undefined`.
 
+  ⚠ eslint-plugin-unicorn(no-null): Do not use `null` literals
+   ╭─[no_null.tsx:1:18]
+ 1 │ foo.insertBefore(null as any)
+   ·                  ────
+   ╰────
+  help: Replace `null` with `undefined`.
+
   ⚠ eslint-plugin-unicorn(no-null): Do not use `null` literals
    ╭─[no_null.tsx:1:23]
  1 │ foo.insertBefore(foo, null, bar)