refactor: resolve various analysis warnings (#1929)

Author: felangel

examples/basic_authentication/pubspec_overrides.yaml

@@ -5,3 +5,6 @@ dependency_overrides:
     path: ../../packages/dart_frog_auth
   dart_frog_lint:
     path: ../../packages/dart_frog_lint
+  # Remove when coverage reporting is fixed.
+  #  https://github.com/dart-lang/test/pull/2594
+  test: 1.26.3

examples/bearer_authentication/pubspec_overrides.yaml

@@ -4,4 +4,7 @@ dependency_overrides:
   dart_frog_auth:
     path: ../../packages/dart_frog_auth
   dart_frog_lint:
-    path: ../../packages/dart_frog_lint
+    path: ../../packages/dart_frog_lint
+  # Remove when coverage reporting is fixed.
+  #  https://github.com/dart-lang/test/pull/2594
+  test: 1.26.3

examples/counter/pubspec_overrides.yaml

@@ -3,3 +3,6 @@ dependency_overrides:
     path: ../../packages/dart_frog
   dart_frog_lint:
     path: ../../packages/dart_frog_lint
+  # Remove when coverage reporting is fixed.
+  #  https://github.com/dart-lang/test/pull/2594
+  test: 1.26.3

examples/echo/pubspec_overrides.yaml

@@ -3,3 +3,6 @@ dependency_overrides:
     path: ../../packages/dart_frog
   dart_frog_lint:
     path: ../../packages/dart_frog_lint
+  # Remove when coverage reporting is fixed.
+  #  https://github.com/dart-lang/test/pull/2594
+  test: 1.26.3

examples/hello_world/pubspec_overrides.yaml

@@ -3,3 +3,6 @@ dependency_overrides:
     path: ../../packages/dart_frog
   dart_frog_lint:
     path: ../../packages/dart_frog_lint
+  # Remove when coverage reporting is fixed.
+  #  https://github.com/dart-lang/test/pull/2594
+  test: 1.26.3

examples/kitchen_sink/pubspec_overrides.yaml

@@ -3,3 +3,6 @@ dependency_overrides:
     path: ../../packages/dart_frog
   dart_frog_lint:
     path: ../../packages/dart_frog_lint
+  # Remove when coverage reporting is fixed.
+  #  https://github.com/dart-lang/test/pull/2594
+  test: 1.26.3

examples/todos/pubspec_overrides.yaml

@@ -3,3 +3,6 @@ dependency_overrides:
     path: ../../packages/dart_frog
   dart_frog_lint:
     path: ../../packages/dart_frog_lint
+  # Remove when coverage reporting is fixed.
+  #  https://github.com/dart-lang/test/pull/2594
+  test: 1.26.3

examples/web_socket_counter/pubspec_overrides.yaml

@@ -3,3 +3,6 @@ dependency_overrides:
     path: ../../packages/dart_frog
   dart_frog_lint:
     path: ../../packages/dart_frog_lint
+  # Remove when coverage reporting is fixed.
+  #  https://github.com/dart-lang/test/pull/2594
+  test: 1.26.3

packages/dart_frog/lib/src/router.dart

@@ -309,8 +309,6 @@ class RouterEntry {
     Middleware? middleware,
     bool mounted = false,
   }) {
-    middleware = middleware ?? ((Handler fn) => fn);
-
     if (!route.startsWith('/')) {
       throw ArgumentError.value(
         route,
@@ -343,7 +341,7 @@ class RouterEntry {
       verb,
       route,
       handler,
-      middleware,
+      middleware ?? ((Handler fn) => fn),
       routePattern,
       params,
       mounted,

packages/dart_frog_test/example/test/routes/dice_test.dart

@@ -30,6 +30,8 @@ void main() {
   test(
     'only allows post method',
     () async {
+      // ignoring for testing.
+      // ignore: experimental_member_use
       await expectNotAllowedMethods(
         route.onRequest,
         contextBuilder: (method) => TestRequestContext(