fix: correctly track interface members

When an interface is a) defined as an ES2015 class and b) assigned to a variable, JSDoc sometimes used the wrong `longname` and `memberof` for members of the interface (specifically, for instance properties).

The root cause was that we weren't resolving `this` correctly within this type of interface. As a result, if you added a JSDoc comment to something like `this.foo = 'bar'`, the doclet for `this.foo` had the wrong `longname` and `memberof`.

Fixing that issue uncovered another issue: When we merged the constructor's doclet with the interface's doclet, we preferred the constructor's doclet. However, the constructor's doclet used the wrong `kind` in this case; we already had code to fix up the `longname` and `memberof` of the combined doclet, but not the `kind`. The fix was to prefer the interface's doclet for all properties.

lib/jsdoc/src/parser.js

@@ -539,7 +539,7 @@ class Parser extends EventEmitter {
                 result = doclet.longname;
             }
             // walk up to the closest class we can find
-            else if (doclet.kind === 'class' || doclet.kind === 'module') {
+            else if (doclet.kind === 'class' || doclet.kind === 'interface' || doclet.kind === 'module') {
                 result = doclet.longname;
             }
             else if (node.enclosingScope) {

lib/jsdoc/src/visitor.js

@@ -329,12 +329,9 @@ function makeConstructorFinisher(parser) {
             return;
         }
 
-        combined = jsdoc.doclet.combine(doclet, parentDoclet);
-        combined.longname = parentDoclet.longname;
-        if (parentDoclet.memberof) {
-            combined.memberof = parentDoclet.memberof;
-        }
-
+        // We prefer the parent doclet because it has the correct kind, longname, and memberof.
+        // The child doclet might or might not have the correct kind, longname, and memberof.
+        combined = jsdoc.doclet.combine(parentDoclet, doclet);
         parser.addResult(combined);
 
         parentDoclet.undocumented = doclet.undocumented = true;

test/fixtures/interface-assignment.js

@@ -0,0 +1,15 @@
+/** @namespace */
+const myCorp = {};
+
+/**
+ * @interface
+ */
+myCorp.IWorker = class IWorker {
+    constructor(workerName) {
+        /** Name of the worker. */
+        this.workerName = workerName;
+    }
+
+    /** Interface for doing some work. */
+    work() {}
+};

test/fixtures/interface-implements2.js

@@ -0,0 +1,23 @@
+/**
+ * @interface
+ */
+class IWorker {
+    /** Interface for doing some work. */
+    work() {}
+}
+
+/**
+ * @implements {IWorker}
+ */
+class MyWorker {
+    /** Do some work. */
+    work() {}
+
+    /** Process a thing. */
+    process() {}
+}
+
+/**
+ * @implements {IWorker}
+ */
+class MyIncompleteWorker {}

test/specs/tags/interfacetag.js

@@ -50,6 +50,50 @@ describe('@interface tag', () => {
         });
     });
 
+    describe('ES2015 classes as interfaces', () => {
+        const docSet2 = jasmine.getDocSetFromFile('test/fixtures/interface-implements2.js');
+        const docSet3 = jasmine.getDocSetFromFile('test/fixtures/interface-assignment.js');
+
+        it('should set the correct kind on the interface', () => {
+            const workerInterface = docSet2.getByLongname('IWorker').filter(d => !d.undocumented)[0];
+
+            expect(workerInterface.kind).toBe('interface');
+        });
+
+        it('should set the correct kind on methods in the interface', () => {
+            const workerInterfaceWork = docSet2.getByLongname('IWorker#work')
+                .filter(d => !d.undocumented)[0];
+
+            expect(workerInterfaceWork.kind).toBe('function');
+        });
+
+        it('should set the correct kind on the implementing class', () => {
+            const workerImpl = docSet2.getByLongname('MyWorker').filter(d => !d.undocumented)[0];
+
+            expect(workerImpl.kind).toBe('class');
+        });
+
+        it('should set the correct kind on an interface assigned to a variable', () => {
+            const workerInterface = docSet3.getByLongname('myCorp.IWorker').filter(d => !d.undocumented)[0];
+
+            expect(workerInterface.kind).toBe('interface');
+        });
+
+        it('should set the correct kind on methods in an interface assigned to a variable', () => {
+            const workerInterfaceWork = docSet3.getByLongname('myCorp.IWorker#work')
+                .filter(d => !d.undocumented)[0];
+
+            expect(workerInterfaceWork.kind).toBe('function');
+        });
+
+        it('should set the correct kind on other members in an interface assigned to a variable', () => {
+            const workerName = docSet3.getByLongname('myCorp.IWorker#workerName')
+                .filter(d => !d.undocumented)[0];
+
+            expect(workerName.kind).toBe('member');
+        });
+    });
+
     describe('Closure Compiler tags', () => {
         afterEach(() => {
             jasmine.restoreTagDictionary();