fix(linter): false positive in no unused vars when importing value used as type (#10690)

camc314 · camc314 · commit 06f1717415ff · 2025-04-29T10:07:38.000Z
I accidently copied a pass test case to the fail array.

```
import { foo } from '';

export type Foo = typeof foo;
```
 is allowed
diff --git a/crates/oxc_linter/src/rules/eslint/no_unused_vars/tests/oxc.rs b/crates/oxc_linter/src/rules/eslint/no_unused_vars/tests/oxc.rs
@@ -1148,6 +1148,7 @@ fn test_type_references() {
             accessor y!: Foo
         }
         ",
+        "import { foo } from 'bar'; export type K = typeof foo",
     ];
 
     let fail = vec![
diff --git a/crates/oxc_linter/src/rules/eslint/no_unused_vars/tests/typescript_eslint.rs b/crates/oxc_linter/src/rules/eslint/no_unused_vars/tests/typescript_eslint.rs
@@ -1402,6 +1402,13 @@ fn test() {
             ",
             None,
         ),
+        (
+            "
+        import { foo } from 'foo';
+        export type Bar = typeof foo;
+            ",
+            None,
+        ),
     ];
 
     let fail = vec![
@@ -1769,13 +1776,6 @@ fn test() {
             ",
             None,
         ),
-        (
-            "
-        import { foo } from 'foo';
-        export type Bar = typeof foo;
-            ",
-            None,
-        ),
     ];
 
     Tester::new(NoUnusedVars::NAME, NoUnusedVars::PLUGIN, pass, fail)
diff --git a/crates/oxc_linter/src/rules/eslint/no_unused_vars/usage.rs b/crates/oxc_linter/src/rules/eslint/no_unused_vars/usage.rs
@@ -137,7 +137,7 @@ impl<'a> Symbol<'_, 'a> {
                     continue;
                 }
 
-                if !self.flags().intersects(SymbolFlags::TypeImport)
+                if !self.flags().intersects(SymbolFlags::TypeImport.union(SymbolFlags::Import))
                     && self.reference_contains_type_query(reference)
                 {
                     continue;
diff --git a/crates/oxc_linter/src/snapshots/eslint_no_unused_vars@typescript-eslint.snap b/crates/oxc_linter/src/snapshots/eslint_no_unused_vars@typescript-eslint.snap
@@ -400,13 +400,3 @@ source: crates/oxc_linter/src/tester.rs
  3 &#9474;           bar: {
    &#9584;&#9472;&#9472;&#9472;&#9472;
   help: Consider removing this declaration.
-
-  &#9888; eslint(no-unused-vars): Identifier 'foo' is imported but never used.
-   &#9581;&#9472;[no_unused_vars.ts:2:18]
- 1 &#9474; 
- 2 &#9474;         import { foo } from 'foo';
-   &middot;                  &#9472;&#9516;&#9472;
-   &middot;                   &#9584;&#9472;&#9472; 'foo' is imported here
- 3 &#9474;         export type Bar = typeof foo;
-   &#9584;&#9472;&#9472;&#9472;&#9472;
-  help: Consider removing this import.

Original file line number	Diff line number	Diff line change
`@@ -1148,6 +1148,7 @@ fn test_type_references() {`
`1148`	`1148`	`accessor y!: Foo`
`1149`	`1149`	`}`
`1150`	`1150`	`",`
	`1151`	`+ "import { foo } from 'bar'; export type K = typeof foo",`
`1151`	`1152`	`];`
`1152`	`1153`
`1153`	`1154`	`let fail = vec![`
Original file line number	Diff line number	Diff line change
`@@ -137,7 +137,7 @@ impl<'a> Symbol<'_, 'a> {`
`137`	`137`	`continue;`
`138`	`138`	`}`
`139`	`139`
`140`		`- if !self.flags().intersects(SymbolFlags::TypeImport)`
	`140`	`+ if !self.flags().intersects(SymbolFlags::TypeImport.union(SymbolFlags::Import))`
`141`	`141`	`&& self.reference_contains_type_query(reference)`
`142`	`142`	`{`
`143`	`143`	`continue;`
-Original file line number
+Diff line change
 │           bar: {
    ╰────
   help: Consider removing this declaration.
+-
 -  ⚠ eslint(no-unused-vars): Identifier 'foo' is imported but never used.
 -   ╭─[no_unused_vars.ts:2:18]
 - 1 │
 - 2 │         import { foo } from 'foo';
 -   ·                  ─┬─
 -   ·                   ╰── 'foo' is imported here
 - 3 │         export type Bar = typeof foo;
 -   ╰────
 -  help: Consider removing this import.