fix: use the last reference definition when checking jest fn scope (#1109)

* fix: use the last reference definition when checking jest fn scope

* test: add case with interface + function merging

Author: G-Rath

src/rules/__tests__/utils.test.ts

@@ -989,7 +989,61 @@ describe('reference checking', () => {
         parser: require.resolve('@typescript-eslint/parser'),
         parserOptions: { sourceType: 'module' },
       },
+      {
+        code: dedent`
+          function it(message: string, fn: () => void): void;
+          function it(cases: unknown[], message: string, fn: () => void): void;
+          function it(...all: any[]): void {}
+  
+          it('is not a jest function', () => {});
+        `,
+        parser: require.resolve('@typescript-eslint/parser'),
+        parserOptions: { sourceType: 'module' },
+      },
+      {
+        code: dedent`
+          interface it {}
+          function it(...all: any[]): void {}
+  
+          it('is not a jest function', () => {});
+        `,
+        parser: require.resolve('@typescript-eslint/parser'),
+        parserOptions: { sourceType: 'module' },
+      },
+      {
+        code: dedent`
+          import { it } from '@jest/globals';
+          import { it } from '../it-utils';
+
+          it('is not a jest function', () => {});
+        `,
+        parser: require.resolve('@typescript-eslint/parser'),
+        parserOptions: { sourceType: 'module' },
+      },
+    ],
+    invalid: [
+      {
+        code: dedent`
+          import { it } from '../it-utils';
+          import { it } from '@jest/globals';
+
+          it('is a jest function', () => {});
+        `,
+        parser: require.resolve('@typescript-eslint/parser'),
+        parserOptions: { sourceType: 'module' },
+        errors: [
+          {
+            messageId: 'details' as const,
+            data: {
+              callType: 'test',
+              numOfArgs: 2,
+              nodeName: 'it',
+            },
+            column: 1,
+            line: 4,
+          },
+        ],
+      },
     ],
-    invalid: [],
   });
 });

src/rules/utils.ts

@@ -893,14 +893,7 @@ const collectReferences = (scope: TSESLint.Scope.Scope) => {
         continue;
       }
 
-      /* istanbul ignore if */
-      if (ref.defs.length > 1) {
-        throw new Error(
-          `Reference unexpected had more than one definition - please file a github issue at https://github.com/jest-community/eslint-plugin-jest`,
-        );
-      }
-
-      const [def] = ref.defs;
+      const def = ref.defs[ref.defs.length - 1];
 
       const importDetails = describePossibleImportDef(def);