"brew upgrade dart" Notice : Error: No available formula with the name "dart"

[GGSDDUAY]

When i use brew upgrade dar in the terminal on mac os, The log notice Error: No available formula with the name "dart";
The flutter doctor -v is:

flutter doctor -v
[✓] Flutter (Channel stable, v1.9.1+hotfix.6, on Mac OS X 10.14.6 18G103, locale
    zh-Hans-CN)
    • Flutter version 1.9.1+hotfix.6 at /Users/czc/developerment/flutter
    • Framework revision 68587a0916 (7 weeks ago), 2019-09-13 19:46:58 -0700
    • Engine revision b863200c37
    • Dart version 2.5.0

 
[✓] Android toolchain - develop for Android devices (Android SDK version 29.0.2)
    • Android SDK at /Users/czc/Library/Android/sdk
    • Android NDK location not configured (optional; useful for native profiling
      support)
    • Platform android-29, build-tools 29.0.2
    • Java binary at: /Applications/Android
      Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build
      1.8.0_202-release-1483-b49-5587405)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 10.3)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 10.3, Build version 10G8
    • CocoaPods version 1.8.4

[✓] Android Studio (version 3.5)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin version 40.2.2
    • Dart plugin version 191.8593
    • Java version OpenJDK Runtime Environment (build
      1.8.0_202-release-1483-b49-5587405)

[✓] IntelliJ IDEA Community Edition (version 2019.2.3)
    • IntelliJ at /Applications/IntelliJ IDEA CE.app
    • Flutter plugin version 40.2.4
    • Dart plugin version 192.7402

[✓] VS Code (version 1.39.2)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.5.1

[✓] Connected device (1 available)
    • iPhone Xʀ • EC2AFEC9-362C-42C4-B645-CBE2E6BD09A6 • ios •
      com.apple.CoreSimulator.SimRuntime.iOS-12-4 (simulator)

• No issues found!

[mraleph]

Make sure that you have run:

$ brew tap dart-lang/dart

before trying to install dart using Homebrew.

[cdrhim]

Solved my problem too.

[ModupeD]

Solved my problem

[kds215]

That did the trick... thanks.