feat(linter): start import fixer for eslint/no-unused-vars (#4849)

crates/oxc_linter/src/rules/eslint/no_unused_vars/fixers/fix_imports.rs

@@ -0,0 +1,34 @@
+use oxc_ast::ast::ImportDeclaration;
+use oxc_span::GetSpan;
+
+use super::{count_whitespace_or_commas, NoUnusedVars, Symbol};
+use crate::fixer::{RuleFix, RuleFixer};
+
+impl NoUnusedVars {
+    #[allow(clippy::unused_self)]
+    pub(in super::super) fn remove_unused_import_declaration<'a>(
+        &self,
+        fixer: RuleFixer<'_, 'a>,
+        symbol: &Symbol<'_, 'a>,
+        import: &ImportDeclaration<'a>,
+    ) -> RuleFix<'a> {
+        let specifiers = import
+                .specifiers
+                .as_ref()
+                .expect("Found an unused variable in an ImportDeclaration with no specifiers. This should be impossible.");
+
+        debug_assert!(
+            !specifiers.is_empty(),
+            "Found an unused variable in an ImportDeclaration with no specifiers. This should be impossible."
+        );
+
+        if specifiers.len() == 1 {
+            return fixer.delete(import).dangerously();
+        }
+        let span = symbol.span();
+        let text_after = fixer.source_text()[(span.end as usize)..].chars();
+        let span = span.expand_right(count_whitespace_or_commas(text_after));
+
+        fixer.delete_range(span).dangerously()
+    }
+}

crates/oxc_linter/src/rules/eslint/no_unused_vars/fixers/mod.rs

@@ -1,3 +1,4 @@
+mod fix_imports;
 mod fix_symbol;
 mod fix_vars;
 

crates/oxc_linter/src/rules/eslint/no_unused_vars/mod.rs

@@ -13,7 +13,7 @@ use std::ops::Deref;
 
 use oxc_ast::AstKind;
 use oxc_macros::declare_oxc_lint;
-use oxc_semantic::{ScopeFlags, SymbolFlags, SymbolId};
+use oxc_semantic::{AstNode, ScopeFlags, SymbolFlags, SymbolId};
 use oxc_span::GetSpan;
 
 use crate::{context::LintContext, rule::Rule};
@@ -209,7 +209,20 @@ impl NoUnusedVars {
             | AstKind::ImportExpression(_)
             | AstKind::ImportDefaultSpecifier(_)
             | AstKind::ImportNamespaceSpecifier(_) => {
-                ctx.diagnostic(diagnostic::imported(symbol));
+                let diagnostic = diagnostic::imported(symbol);
+                let declaration =
+                    symbol.iter_self_and_parents().map(AstNode::kind).find_map(|kind| match kind {
+                        AstKind::ImportDeclaration(import) => Some(import),
+                        _ => None,
+                    });
+
+                if let Some(declaration) = declaration {
+                    ctx.diagnostic_with_suggestion(diagnostic, |fixer| {
+                        self.remove_unused_import_declaration(fixer, symbol, declaration)
+                    });
+                } else {
+                    ctx.diagnostic(diagnostic);
+                }
             }
             AstKind::VariableDeclarator(decl) => {
                 if self.is_allowed_variable_declaration(symbol, decl) {

crates/oxc_linter/src/rules/eslint/no_unused_vars/tests/oxc.rs

@@ -496,7 +496,47 @@ fn test_imports() {
         ("import { a as b } from 'a'; console.log(a)", None),
     ];
 
+    let fix = vec![
+        // None used
+        ("import foo from './foo';", "", None, FixKind::DangerousSuggestion),
+        ("import * as foo from './foo';", "", None, FixKind::DangerousSuggestion),
+        ("import { Foo } from './foo';", "", None, FixKind::DangerousSuggestion),
+        ("import { Foo as Bar } from './foo';", "", None, FixKind::DangerousSuggestion),
+        // Some used
+        (
+            "import foo, { bar } from './foo'; bar();",
+            "import { bar } from './foo'; bar();",
+            None,
+            FixKind::DangerousSuggestion,
+        ),
+        (
+            "import foo, { bar } from './foo'; foo();",
+            "import foo, { } from './foo'; foo();",
+            None,
+            FixKind::DangerousSuggestion,
+        ),
+        (
+            "import { foo, bar, baz } from './foo'; foo(bar);",
+            "import { foo, bar, } from './foo'; foo(bar);",
+            None,
+            FixKind::DangerousSuggestion,
+        ),
+        (
+            "import { foo, bar, baz } from './foo'; foo(baz);",
+            "import { foo, baz } from './foo'; foo(baz);",
+            None,
+            FixKind::DangerousSuggestion,
+        ),
+        (
+            "import { foo, bar, baz } from './foo'; bar(baz);",
+            "import { bar, baz } from './foo'; bar(baz);",
+            None,
+            FixKind::DangerousSuggestion,
+        ),
+    ];
+
     Tester::new(NoUnusedVars::NAME, pass, fail)
+        .expect_fix(fix)
         .with_snapshot_suffix("oxc-imports")
         .test_and_snapshot();
 }