Fix the error caused by the same path and alias of RouteConfig

src/create-route-map.js

@@ -112,32 +112,39 @@ function addRouteRecord (
     })
   }
 
-  if (route.alias !== undefined) {
-    const aliases = Array.isArray(route.alias)
-      ? route.alias
-      : [route.alias]
-
-    aliases.forEach(alias => {
-      const aliasRoute = {
-        path: alias,
-        children: route.children
-      }
-      addRouteRecord(
-        pathList,
-        pathMap,
-        nameMap,
-        aliasRoute,
-        parent,
-        record.path || '/' // matchAs
-      )
-    })
-  }
-
   if (!pathMap[record.path]) {
     pathList.push(record.path)
     pathMap[record.path] = record
   }
 
+  if (route.alias !== undefined) {
+    if (route.alias !== path) {
+      const aliases = Array.isArray(route.alias)
+        ? route.alias
+        : [route.alias]
+
+      aliases.forEach(alias => {
+        const aliasRoute = {
+          path: alias,
+          children: route.children
+        }
+        addRouteRecord(
+          pathList,
+          pathMap,
+          nameMap,
+          aliasRoute,
+          parent,
+          record.path || '/' // matchAs
+        )
+      })
+    } else if (process.env.NODE_ENV !== 'production') {
+      warn(
+        false,
+        `Path with the same value as an alias: "${path}"`
+      )
+    }
+  }
+
   if (name) {
     if (!nameMap[name]) {
       nameMap[name] = record

test/unit/specs/create-map.spec.js

@@ -97,6 +97,18 @@ describe('Creating Route Map', function () {
     expect(console.warn.calls.argsFor(0)[0]).toMatch('vue-router] Duplicate param keys in route with path: "/foo/:id/bar/:id"')
   })
 
+  it('in development, warn path with the same value as an alias', () => {
+    process.env.NODE_ENV = 'development'
+    maps = createRouteMap([
+      {
+        path: '/foo-alias', component: Foo,
+        alias: '/foo-alias'
+      }
+    ])
+    expect(console.warn).toHaveBeenCalled()
+    expect(console.warn.calls.argsFor(0)[0]).toMatch('vue-router] Path with the same value as an alias: "/foo-alias"')
+  })
+
   describe('path-to-regexp options', function () {
     const routes = [
       { path: '/foo', name: 'foo', component: Foo },