fix: interfaces can implement interfaces

src/nexusDecorators.ts

@@ -288,7 +288,7 @@ function gatherRecursiveMeta<O extends MetaClass>(cls: O) {
       fields = fields.concat(currentFields);
     }
     if (Array.isArray(currentInterfaces)) {
-      interfaces = currentInterfaces.concat(currentInterfaces);
+      interfaces = interfaces.concat(currentInterfaces);
     }
     walkingProto = Object.getPrototypeOf(walkingProto);
   }

test/__snapshots__/nexusDecorators.spec.ts.snap

@@ -12,6 +12,34 @@ type Query {
 "
 `;
 
+exports[`nexus-decorators allows interfaces to implement interfaces 1`] = `
+"interface Node {
+  id: ID!
+}
+
+type Post implements Node & Something {
+  id: ID!
+  name: String
+  title: String
+}
+
+type Query {
+  ok: Boolean!
+}
+
+interface Something implements Node {
+  id: ID!
+  name: String
+}
+
+type User implements Node & Something {
+  email: String
+  id: ID!
+  name: String
+}
+"
+`;
+
 exports[`nexus-decorators creates a schema 1`] = `
 "\\"\\"\\"Implements the Node id\\"\\"\\"
 interface Node {

test/nexusDecorators.spec.ts

@@ -130,4 +130,47 @@ describe("nexus-decorators", () => {
     });
     expect(printSchema(lexicographicSortSchema(out.schema))).toMatchSnapshot();
   });
+
+  it("allows interfaces to implement interfaces", async () => {
+    @nxs.interfaceType({
+      resolveType() {},
+    })
+    abstract class Node {
+      @nxs.field.nonNull.id()
+      id() {
+        return "ID";
+      }
+    }
+
+    @nxs.interfaceType({
+      resolveType() {},
+    })
+    abstract class Something extends Node {
+      @nxs.field.string()
+      get name() {
+        return "Something";
+      }
+    }
+
+    @nxs.objectType()
+    class User extends Something {
+      @nxs.field.string()
+      get email() {
+        return "ok";
+      }
+    }
+
+    @nxs.objectType()
+    class Post extends Something {
+      @nxs.field.string()
+      get title() {
+        return "ok";
+      }
+    }
+
+    const out = core.makeSchemaInternal({
+      types: [User, Post, User],
+    });
+    expect(printSchema(lexicographicSortSchema(out.schema))).toMatchSnapshot();
+  });
 });