diff --git a/packages/flutter_tools/lib/src/android/android_device.dart b/packages/flutter_tools/lib/src/android/android_device.dart
index 53a0065..975fd27 100644
--- a/packages/flutter_tools/lib/src/android/android_device.dart
+++ b/packages/flutter_tools/lib/src/android/android_device.dart
@@ -177,7 +177,7 @@
       } finally {
         console.destroy();
       }
-    } catch (e) {
+    } on Exception catch (e) {
       globals.printTrace('Failed to fetch avd name for emulator at $host:$port: $e');
       // If we fail to connect to the device, we should not fail so just return
       // an empty name. This data is best-effort.
@@ -299,7 +299,7 @@
         return true;
       }
       globals.printError('The ADB at "${getAdbPath(androidSdk)}" is too old; please install version 1.0.39 or later.');
-    } catch (error, trace) {
+    } on Exception catch (error, trace) {
       globals.printError('Error running ADB: $error', stackTrace: trace);
     }
 
@@ -335,7 +335,7 @@
       }
 
       return true;
-    } catch (e, stacktrace) {
+    } on Exception catch (e, stacktrace) {
       globals.printError('Unexpected failure from adb: $e');
       globals.printError('Stacktrace: $stacktrace');
       return false;
@@ -366,7 +366,7 @@
     try {
       final RunResult listOut = await runAdbCheckedAsync(<String>['shell', 'pm', 'list', 'packages', app.id]);
       return LineSplitter.split(listOut.stdout).contains('package:${app.id}');
-    } catch (error) {
+    } on Exception catch (error) {
       globals.printTrace('$error');
       return false;
     }
@@ -432,7 +432,7 @@
         throwOnError: true,
       );
       uninstallOut = uninstallResult.stdout;
-    } catch (error) {
+    } on Exception catch (error) {
       globals.printError('adb uninstall failed: $error');
       return false;
     }
@@ -631,7 +631,7 @@
       }
 
       return LaunchResult.succeeded(observatoryUri: observatoryUri);
-    } catch (error) {
+    } on Exception catch (error) {
       globals.printError('Error waiting for a debug connection: $error');
       return LaunchResult.failed();
     } finally {
@@ -696,7 +696,7 @@
       output = runAdbCheckedSync(<String>[
         'shell', '-x', 'logcat', '-v', 'time', '-t', '1'
       ]);
-    } catch (error) {
+    } on Exception catch (error) {
       globals.printError('Failed to extract the most recent timestamp from the Android log: $error.');
       return null;
     }
diff --git a/packages/flutter_tools/lib/src/android/android_sdk.dart b/packages/flutter_tools/lib/src/android/android_sdk.dart
index bb4a429..567ff46 100644
--- a/packages/flutter_tools/lib/src/android/android_sdk.dart
+++ b/packages/flutter_tools/lib/src/android/android_sdk.dart
@@ -492,7 +492,7 @@
         .map((FileSystemEntity entity) {
           try {
             return Version.parse(entity.basename);
-          } catch (error) {
+          } on Exception {
             return null;
           }
         })
@@ -518,7 +518,7 @@
               .group(1);
           platformVersion = int.parse(versionString);
         }
-      } catch (error) {
+      } on Exception {
         return null;
       }
 
@@ -583,7 +583,7 @@
             return fileSystem.path.join(javaHome, 'bin', 'java');
           }
         }
-      } catch (_) { /* ignore */ }
+      } on Exception catch (_) { /* ignore */ }
     }
 
     // Fallback to PATH based lookup.
diff --git a/packages/flutter_tools/lib/src/android/android_studio.dart b/packages/flutter_tools/lib/src/android/android_studio.dart
index 961b673..eb07945 100644
--- a/packages/flutter_tools/lib/src/android/android_studio.dart
+++ b/packages/flutter_tools/lib/src/android/android_studio.dart
@@ -93,7 +93,7 @@
       installPath = globals.fs
           .file(globals.fs.path.join(homeDotDir.path, 'system', '.home'))
           .readAsStringSync();
-    } catch (e) {
+    } on Exception {
       // ignored, installPath will be null, which is handled below
     }
     if (installPath != null && globals.fs.isDirectorySync(installPath)) {
@@ -200,7 +200,7 @@
             _checkForStudio(directory.path);
           }
         }
-      } catch (e) {
+      } on Exception catch (e) {
         globals.printTrace('Exception while looking for Android Studio: $e');
       }
     }
diff --git a/packages/flutter_tools/lib/src/android/android_workflow.dart b/packages/flutter_tools/lib/src/android/android_workflow.dart
index 0043926..ef3d5fa 100644
--- a/packages/flutter_tools/lib/src/android/android_workflow.dart
+++ b/packages/flutter_tools/lib/src/android/android_workflow.dart
@@ -122,7 +122,7 @@
           final List<String> versionLines = (result.stderr as String).split('\n');
           javaVersionText = versionLines.length >= 2 ? versionLines[1] : versionLines[0];
         }
-      } catch (error) {
+      } on Exception catch (error) {
         _logger.printTrace(error.toString());
       }
       if (javaVersionText == null || javaVersionText.isEmpty) {
@@ -287,7 +287,7 @@
         final List<String> versionLines = (result.stderr as String).split('\n');
         javaVersion = versionLines.length >= 2 ? versionLines[1] : versionLines[0];
       }
-    } catch (error) {
+    } on Exception catch (error) {
       globals.printTrace(error.toString());
     }
     if (javaVersion == null) {
@@ -389,7 +389,7 @@
           globals.stdio.addStdoutStream(process.stdout),
           globals.stdio.addStderrStream(process.stderr),
         ]);
-      } catch (err, stack) {
+      } on Exception catch (err, stack) {
         globals.printTrace('Echoing stdout or stderr from the license subprocess failed:');
         globals.printTrace('$err\n$stack');
       }
diff --git a/packages/flutter_tools/lib/src/asset.dart b/packages/flutter_tools/lib/src/asset.dart
index 681d503..b0f5072 100644
--- a/packages/flutter_tools/lib/src/asset.dart
+++ b/packages/flutter_tools/lib/src/asset.dart
@@ -128,7 +128,7 @@
     FlutterManifest flutterManifest;
     try {
       flutterManifest = FlutterManifest.createFromPath(manifestPath);
-    } catch (e) {
+    } on Exception catch (e) {
       globals.printStatus('Error detected in pubspec.yaml:', emphasis: true);
       globals.printError('$e');
       return 1;
diff --git a/packages/flutter_tools/lib/src/base/async_guard.dart b/packages/flutter_tools/lib/src/base/async_guard.dart
index 4515174..d25cf58 100644
--- a/packages/flutter_tools/lib/src/base/async_guard.dart
+++ b/packages/flutter_tools/lib/src/base/async_guard.dart
@@ -112,7 +112,9 @@
       if (!completer.isCompleted) {
         completer.complete(result);
       }
-    } catch (e, s) {
+    // This catches all exceptions so that they can be propagated to the
+    // caller-supplied error handling or the completer.
+    } catch (e, s) { // ignore: avoid_catches_without_on_clauses
       handleError(e, s);
     }
   }, onError: (Object e, StackTrace s) {
diff --git a/packages/flutter_tools/lib/src/base/fingerprint.dart b/packages/flutter_tools/lib/src/base/fingerprint.dart
index 815acc2..f20e107 100644
--- a/packages/flutter_tools/lib/src/base/fingerprint.dart
+++ b/packages/flutter_tools/lib/src/base/fingerprint.dart
@@ -66,7 +66,7 @@
       final Fingerprint oldFingerprint = Fingerprint.fromJson(fingerprintFile.readAsStringSync());
       final Fingerprint newFingerprint = buildFingerprint();
       return oldFingerprint == newFingerprint;
-    } catch (e) {
+    } on Exception catch (e) {
       // Log exception and continue, fingerprinting is only a performance improvement.
       globals.printTrace('Fingerprint check error: $e');
     }
@@ -77,7 +77,7 @@
     try {
       final Fingerprint fingerprint = buildFingerprint();
       globals.fs.file(fingerprintPath).writeAsStringSync(fingerprint.toJson());
-    } catch (e) {
+    } on Exception catch (e) {
       // Log exception and continue, fingerprinting is only a performance improvement.
       globals.printTrace('Fingerprint write error: $e');
     }
@@ -103,7 +103,7 @@
     final Iterable<File> files = inputPaths.map<File>(globals.fs.file);
     final Iterable<File> missingInputs = files.where((File file) => !file.existsSync());
     if (missingInputs.isNotEmpty) {
-      throw ArgumentError('Missing input files:\n' + missingInputs.join('\n'));
+      throw Exception('Missing input files:\n' + missingInputs.join('\n'));
     }
 
     _checksums = <String, String>{};
@@ -116,14 +116,14 @@
 
   /// Creates a Fingerprint from serialized JSON.
   ///
-  /// Throws [ArgumentError], if there is a version mismatch between the
+  /// Throws [Exception], if there is a version mismatch between the
   /// serializing framework and this framework.
   Fingerprint.fromJson(String jsonData) {
     final Map<String, dynamic> content = castStringKeyedMap(json.decode(jsonData));
 
     final String version = content['version'] as String;
     if (version != globals.flutterVersion.frameworkRevision) {
-      throw ArgumentError('Incompatible fingerprint version: $version');
+      throw Exception('Incompatible fingerprint version: $version');
     }
     _checksums = castStringKeyedMap(content['files'])?.cast<String,String>() ?? <String, String>{};
     _properties = castStringKeyedMap(content['properties'])?.cast<String,String>() ?? <String, String>{};
@@ -182,8 +182,11 @@
   // outfile1 outfile2 : file1.dart file2.dart file3.dart
   final String contents = globals.fs.file(depfilePath).readAsStringSync();
 
-  final String dependencies = contents.split(': ')[1];
-  return dependencies
+  final List<String> dependencies = contents.split(': ');
+  if (dependencies.length < 2) {
+    throw Exception('malformed depfile');
+  }
+  return dependencies[1]
       .replaceAllMapped(_separatorExpr, (Match match) => '${match.group(1)}\n')
       .split('\n')
       .map<String>((String path) => path.replaceAllMapped(_escapeExpr, (Match match) => match.group(1)).trim())
diff --git a/packages/flutter_tools/lib/src/base/logger.dart b/packages/flutter_tools/lib/src/base/logger.dart
index 0f52351..f5c0544 100644
--- a/packages/flutter_tools/lib/src/base/logger.dart
+++ b/packages/flutter_tools/lib/src/base/logger.dart
@@ -364,7 +364,8 @@
       ? message
       : message.replaceAll('🔥', '')
                .replaceAll('✗', 'X')
-               .replaceAll('✓', '√');
+               .replaceAll('✓', '√')
+               .replaceAll('🔨', '');
     _stdio.stdoutWrite(windowsMessage);
   }
 }
diff --git a/packages/flutter_tools/lib/src/base/os.dart b/packages/flutter_tools/lib/src/base/os.dart
index 65c8b5a..099a71f 100644
--- a/packages/flutter_tools/lib/src/base/os.dart
+++ b/packages/flutter_tools/lib/src/base/os.dart
@@ -136,7 +136,7 @@
         return findFreePort(ipv6: true);
       }
       _logger.printTrace('findFreePort failed: $e');
-    } catch (e) {
+    } on Exception catch (e) {
       // Failures are signaled by a return value of 0 from this function.
       _logger.printTrace('findFreePort failed: $e');
     } finally {
diff --git a/packages/flutter_tools/lib/src/base/process.dart b/packages/flutter_tools/lib/src/base/process.dart
index d8b5d74..eddf2c5 100644
--- a/packages/flutter_tools/lib/src/base/process.dart
+++ b/packages/flutter_tools/lib/src/base/process.dart
@@ -367,7 +367,7 @@
           stdioFuture = stdioFuture.timeout(const Duration(seconds: 1));
         }
         await stdioFuture;
-      } catch (_) {
+      } on Exception catch (_) {
         // Ignore errors on the process' stdout and stderr streams. Just capture
         // whatever we got, and use the exit code
       }
@@ -539,7 +539,7 @@
     _traceCommand(cli);
     try {
       return _processManager.runSync(cli, environment: environment).exitCode == 0;
-    } catch (error) {
+    } on Exception catch (error) {
       _logger.printTrace('$cli failed with $error');
       return false;
     }
@@ -553,7 +553,7 @@
     _traceCommand(cli);
     try {
       return (await _processManager.run(cli, environment: environment)).exitCode == 0;
-    } catch (error) {
+    } on Exception catch (error) {
       _logger.printTrace('$cli failed with $error');
       return false;
     }
diff --git a/packages/flutter_tools/lib/src/base/signals.dart b/packages/flutter_tools/lib/src/base/signals.dart
index 28b9e67..dbbbd76 100644
--- a/packages/flutter_tools/lib/src/base/signals.dart
+++ b/packages/flutter_tools/lib/src/base/signals.dart
@@ -117,7 +117,7 @@
     for (final SignalHandler handler in _handlersList[s]) {
       try {
         await asyncGuard<void>(() async => handler(s));
-      } catch (e) {
+      } on Exception catch (e) {
         if (_errorStreamController.hasListener) {
           _errorStreamController.add(e);
         }
diff --git a/packages/flutter_tools/lib/src/build_info.dart b/packages/flutter_tools/lib/src/build_info.dart
index 28ab800..a0c7220 100644
--- a/packages/flutter_tools/lib/src/build_info.dart
+++ b/packages/flutter_tools/lib/src/build_info.dart
@@ -395,8 +395,7 @@
     case 'x86_64':
       return DarwinArch.x86_64;
   }
-  assert(false);
-  return null;
+  throw Exception('Unsupported iOS arch name "$arch"');
 }
 
 String getNameForTargetPlatform(TargetPlatform platform, {DarwinArch darwinArch}) {
@@ -477,8 +476,7 @@
     case 'android-x86':
       return AndroidArch.x86;
   }
-  assert(false);
-  return null;
+  throw Exception('Unsupported Android arch name "$platform"');
 }
 
 String getNameForAndroidArch(AndroidArch arch) {
diff --git a/packages/flutter_tools/lib/src/build_system/build_system.dart b/packages/flutter_tools/lib/src/build_system/build_system.dart
index 0ef5786..53370f6 100644
--- a/packages/flutter_tools/lib/src/build_system/build_system.dart
+++ b/packages/flutter_tools/lib/src/build_system/build_system.dart
@@ -582,7 +582,7 @@
           previousFile.deleteSync();
         }
       }
-    } catch (exception, stackTrace) {
+    } on Exception catch (exception, stackTrace) {
       // TODO(jonahwilliams): throw specific exception for expected errors to mark
       // as non-fatal. All others should be fatal.
       node.target.clearStamp(environment);
diff --git a/packages/flutter_tools/lib/src/build_system/file_hash_store.dart b/packages/flutter_tools/lib/src/build_system/file_hash_store.dart
index b1b679e..ecd3d48 100644
--- a/packages/flutter_tools/lib/src/build_system/file_hash_store.dart
+++ b/packages/flutter_tools/lib/src/build_system/file_hash_store.dart
@@ -115,8 +115,8 @@
     FileStorage fileStorage;
     try {
       fileStorage = FileStorage.fromBuffer(data);
-    } catch (err) {
-      _logger.printTrace('Filestorage format changed');
+    } on Exception catch (err) {
+      _logger.printTrace('Filestorage format changed: $err');
       cacheFile.deleteSync();
       return;
     }
diff --git a/packages/flutter_tools/lib/src/build_system/targets/ios.dart b/packages/flutter_tools/lib/src/build_system/targets/ios.dart
index 668424e..f69bfe0 100644
--- a/packages/flutter_tools/lib/src/build_system/targets/ios.dart
+++ b/packages/flutter_tools/lib/src/build_system/targets/ios.dart
@@ -374,8 +374,8 @@
 Future<RunResult> createStubAppFramework(File outputFile, SdkType sdk, { bool include32Bit = true }) async {
   try {
     outputFile.createSync(recursive: true);
-  } catch (e) {
-    throwToolExit('Failed to create App.framework stub at ${outputFile.path}');
+  } on Exception catch (e) {
+    throwToolExit('Failed to create App.framework stub at ${outputFile.path}: $e');
   }
 
   final Directory tempDir = globals.fs.systemTempDirectory.createTempSync('flutter_tools_stub_source.');
@@ -418,8 +418,8 @@
       tempDir.deleteSync(recursive: true);
     } on FileSystemException catch (_) {
       // Best effort. Sometimes we can't delete things from system temp.
-    } catch (e) {
-      throwToolExit('Failed to create App.framework stub at ${outputFile.path}');
+    } on Exception catch (e) {
+      throwToolExit('Failed to create App.framework stub at ${outputFile.path}: $e');
     }
   }
 }
diff --git a/packages/flutter_tools/lib/src/build_system/targets/macos.dart b/packages/flutter_tools/lib/src/build_system/targets/macos.dart
index a59cdba..00091cb 100644
--- a/packages/flutter_tools/lib/src/build_system/targets/macos.dart
+++ b/packages/flutter_tools/lib/src/build_system/targets/macos.dart
@@ -329,7 +329,7 @@
       try {
         final File sourceFile = environment.buildDir.childFile('app.dill');
         sourceFile.copySync(assetDirectory.childFile('kernel_blob.bin').path);
-      } catch (err) {
+      } on Exception catch (err) {
         throw Exception('Failed to copy app.dill: $err');
       }
       // Copy precompiled runtimes.
@@ -342,7 +342,7 @@
             assetDirectory.childFile('vm_snapshot_data').path);
         globals.fs.file(isolateSnapshotData).copySync(
             assetDirectory.childFile('isolate_snapshot_data').path);
-      } catch (err) {
+      } on Exception catch (err) {
         throw Exception('Failed to copy precompiled runtimes: $err');
       }
     }
diff --git a/packages/flutter_tools/lib/src/cache.dart b/packages/flutter_tools/lib/src/cache.dart
index bfbde09..34c5990 100644
--- a/packages/flutter_tools/lib/src/cache.dart
+++ b/packages/flutter_tools/lib/src/cache.dart
@@ -403,7 +403,7 @@
     if (!cachedFile.existsSync()) {
       try {
         await downloadFile(url, cachedFile);
-      } catch (e) {
+      } on Exception catch (e) {
         throwToolExit('Failed to fetch third-party artifact $url: $e');
       }
     }
@@ -597,7 +597,8 @@
         try {
           await cache.downloadFile(url, tempFile);
           status.stop();
-        } catch (exception) {
+        // The exception is rethrown, so don't catch only Exceptions.
+        } catch (exception) { // ignore: avoid_catches_without_on_clauses
           status.cancel();
           rethrow;
         }
diff --git a/packages/flutter_tools/lib/src/commands/analyze_base.dart b/packages/flutter_tools/lib/src/commands/analyze_base.dart
index 63fb3dc..2190d80 100644
--- a/packages/flutter_tools/lib/src/commands/analyze_base.dart
+++ b/packages/flutter_tools/lib/src/commands/analyze_base.dart
@@ -33,7 +33,7 @@
         } finally {
           resultsFile.close();
         }
-      } catch (e) {
+      } on Exception catch (e) {
         globals.printError('Failed to save output to "${argResults['write']}": $e');
       }
     }
diff --git a/packages/flutter_tools/lib/src/commands/assemble.dart b/packages/flutter_tools/lib/src/commands/assemble.dart
index 4dac90e..4a0a018 100644
--- a/packages/flutter_tools/lib/src/commands/assemble.dart
+++ b/packages/flutter_tools/lib/src/commands/assemble.dart
@@ -104,7 +104,7 @@
         CustomDimensions.commandBuildBundleTargetPlatform: localEnvironment.defines['TargetPlatform'],
         CustomDimensions.commandBuildBundleIsModule: '${futterProject.isModule}',
       };
-    } catch (err) {
+    } on Exception {
       // We've failed to send usage.
     }
     return const <CustomDimensions, String>{};
diff --git a/packages/flutter_tools/lib/src/commands/attach.dart b/packages/flutter_tools/lib/src/commands/attach.dart
index a1f8530..941ad3b 100644
--- a/packages/flutter_tools/lib/src/commands/attach.dart
+++ b/packages/flutter_tools/lib/src/commands/attach.dart
@@ -114,7 +114,7 @@
     }
     try {
       return int.parse(stringArg('debug-port'));
-    } catch (error) {
+    } on Exception catch (error) {
       throwToolExit('Invalid port for `--debug-port`: $error');
     }
     return null;
@@ -222,7 +222,7 @@
         try {
           isolateDiscoveryProtocol = device.getIsolateDiscoveryProtocol(module);
           observatoryUri = Stream<Uri>.value(await isolateDiscoveryProtocol.uri).asBroadcastStream();
-        } catch (_) {
+        } on Exception {
           isolateDiscoveryProtocol?.dispose();
           final List<ForwardedPort> ports = device.portForwarder.forwardedPorts.toList();
           for (final ForwardedPort port in ports) {
@@ -292,7 +292,7 @@
             globals.fs.currentDirectory,
             LaunchMode.attach,
           );
-        } catch (error) {
+        } on Exception catch (error) {
           throwToolExit(error.toString());
         }
         result = await app.runner.waitForAppToFinish();
diff --git a/packages/flutter_tools/lib/src/commands/clean.dart b/packages/flutter_tools/lib/src/commands/clean.dart
index 5035f9c..24a47ed 100644
--- a/packages/flutter_tools/lib/src/commands/clean.dart
+++ b/packages/flutter_tools/lib/src/commands/clean.dart
@@ -75,7 +75,7 @@
       for (final String scheme in projectInfo.schemes) {
         xcodeProjectInterpreter.cleanWorkspace(xcodeWorkspace.path, scheme);
       }
-    } catch (error) {
+    } on Exception catch (error) {
       globals.printTrace('Could not clean Xcode workspace: $error');
     } finally {
       xcodeStatus?.stop();
diff --git a/packages/flutter_tools/lib/src/commands/create.dart b/packages/flutter_tools/lib/src/commands/create.dart
index 484ea58..71a3973 100644
--- a/packages/flutter_tools/lib/src/commands/create.dart
+++ b/packages/flutter_tools/lib/src/commands/create.dart
@@ -264,7 +264,7 @@
         outputFile.writeAsStringSync(samplesJson);
         globals.printStatus('Wrote samples JSON to "$outputFilePath"');
       }
-    } catch (e) {
+    } on Exception catch (e) {
       throwToolExit('Failed to write samples JSON to "$outputFilePath": $e', exitCode: 2);
     }
   }
diff --git a/packages/flutter_tools/lib/src/commands/daemon.dart b/packages/flutter_tools/lib/src/commands/daemon.dart
index 9427164..a7825f6 100644
--- a/packages/flutter_tools/lib/src/commands/daemon.dart
+++ b/packages/flutter_tools/lib/src/commands/daemon.dart
@@ -175,7 +175,7 @@
           completer.complete(request['result']);
         }
       }
-    } catch (error, trace) {
+    } on Exception catch (error, trace) {
       _send(<String, dynamic>{
         'id': id,
         'error': _toJsonable(error),
@@ -414,7 +414,7 @@
       return <String, Object>{
         'platforms': result,
       };
-    } catch (err, stackTrace) {
+    } on Exception catch (err, stackTrace) {
       sendEvent('log', <String, dynamic>{
         'log': 'Failed to parse project metadata',
         'stackTrace': stackTrace.toString(),
@@ -596,7 +596,7 @@
           appStartedCompleter: appStartedCompleter,
         );
         _sendAppEvent(app, 'stop');
-      } catch (error, trace) {
+      } on Exception catch (error, trace) {
         _sendAppEvent(app, 'stop', <String, dynamic>{
           'error': _toJsonable(error),
           'trace': '$trace',
@@ -780,7 +780,7 @@
         try {
           final Map<String, Object> response = await _deviceToMap(device);
           sendEvent(eventName, response);
-        } catch (err) {
+        } on Exception catch (err) {
           globals.printError('$err');
         }
       });
diff --git a/packages/flutter_tools/lib/src/commands/drive.dart b/packages/flutter_tools/lib/src/commands/drive.dart
index 6ea5281..3b5fd1d 100644
--- a/packages/flutter_tools/lib/src/commands/drive.dart
+++ b/packages/flutter_tools/lib/src/commands/drive.dart
@@ -261,7 +261,7 @@
       try {
         await window.setLocation(const math.Point<int>(0, 0));
         await window.setSize(math.Rectangle<int>(0, 0, x, y));
-      } catch (_) {
+      } on Exception {
        // Error might be thrown in some browsers.
       }
 
@@ -278,7 +278,7 @@
 
     try {
       await testRunner(<String>[testFile], environment);
-    } catch (error, stackTrace) {
+    } on Exception catch (error, stackTrace) {
       if (error is ToolExit) {
         rethrow;
       }
diff --git a/packages/flutter_tools/lib/src/commands/generate.dart b/packages/flutter_tools/lib/src/commands/generate.dart
index 3f94441..c124182 100644
--- a/packages/flutter_tools/lib/src/commands/generate.dart
+++ b/packages/flutter_tools/lib/src/commands/generate.dart
@@ -52,8 +52,8 @@
         globals.printError(stackData[0] as String);
         globals.printError(stackData[1] as String);
         globals.printError(StackTrace.fromString(stackData[2] as String).toString());
-      } catch (err) {
-        globals.printError('Error reading error in ${errorFile.path}');
+      } on Exception catch (err) {
+        globals.printError('Error reading error in ${errorFile.path}: $err');
       }
     }
     return FlutterCommandResult.fail();
diff --git a/packages/flutter_tools/lib/src/commands/packages.dart b/packages/flutter_tools/lib/src/commands/packages.dart
index b36fbf5..0a7e76b 100644
--- a/packages/flutter_tools/lib/src/commands/packages.dart
+++ b/packages/flutter_tools/lib/src/commands/packages.dart
@@ -98,7 +98,8 @@
       );
       pubGetTimer.stop();
       flutterUsage.sendTiming('pub', 'get', pubGetTimer.elapsed, label: 'success');
-    } catch (_) {
+    // Not limiting to catching Exception because the exception is rethrown.
+    } catch (_) { // ignore: avoid_catches_without_on_clauses
       pubGetTimer.stop();
       flutterUsage.sendTiming('pub', 'get', pubGetTimer.elapsed, label: 'failure');
       rethrow;
diff --git a/packages/flutter_tools/lib/src/commands/run.dart b/packages/flutter_tools/lib/src/commands/run.dart
index 15fa50a..0c3a8f0 100644
--- a/packages/flutter_tools/lib/src/commands/run.dart
+++ b/packages/flutter_tools/lib/src/commands/run.dart
@@ -420,7 +420,7 @@
           dillOutputPath: stringArg('output-dill'),
           ipv6: ipv6,
         );
-      } catch (error) {
+      } on Exception catch (error) {
         throwToolExit(error.toString());
       }
       final DateTime appStartedTime = systemClock.now();
diff --git a/packages/flutter_tools/lib/src/commands/screenshot.dart b/packages/flutter_tools/lib/src/commands/screenshot.dart
index a64d1cc..5d830e7 100644
--- a/packages/flutter_tools/lib/src/commands/screenshot.dart
+++ b/packages/flutter_tools/lib/src/commands/screenshot.dart
@@ -116,7 +116,7 @@
     );
     try {
       await device.takeScreenshot(outputFile);
-    } catch (error) {
+    } on Exception catch (error) {
       throwToolExit('Error taking screenshot: $error');
     }
     _showOutputFileInfo(outputFile);
diff --git a/packages/flutter_tools/lib/src/commands/unpack.dart b/packages/flutter_tools/lib/src/commands/unpack.dart
index 07587d6..885c4dd 100644
--- a/packages/flutter_tools/lib/src/commands/unpack.dart
+++ b/packages/flutter_tools/lib/src/commands/unpack.dart
@@ -150,7 +150,7 @@
       } else {
         globals.printTrace('Artifacts for version $targetHash already present.');
       }
-    } catch (error, stackTrace) {
+    } on Exception catch (error, stackTrace) {
       globals.printError(stackTrace.toString());
       globals.printError(error.toString());
       return false;
@@ -200,8 +200,8 @@
       }
 
       globals.printTrace('Copied artifacts from $sourceDirectory.');
-    } catch (e, stackTrace) {
-      globals.printError(e.message as String);
+    } on Exception catch (e, stackTrace) {
+      globals.printError(e.toString());
       globals.printError(stackTrace.toString());
       return false;
     }
diff --git a/packages/flutter_tools/lib/src/commands/upgrade.dart b/packages/flutter_tools/lib/src/commands/upgrade.dart
index d423513..840e265 100644
--- a/packages/flutter_tools/lib/src/commands/upgrade.dart
+++ b/packages/flutter_tools/lib/src/commands/upgrade.dart
@@ -210,7 +210,7 @@
         throwOnError: true,
         workingDirectory: workingDirectory,
       );
-    } catch (e) {
+    } on Exception {
       throwToolExit(
         'Unable to upgrade Flutter: no origin repository configured. '
         "Run 'git remote add origin "
@@ -279,7 +279,7 @@
       final FlutterVersion newFlutterVersion = FlutterVersion(const SystemClock(), workingDirectory);
       alreadyUpToDate = newFlutterVersion.channel == oldFlutterVersion.channel &&
         newFlutterVersion.frameworkRevision == oldFlutterVersion.frameworkRevision;
-    } catch (e) {
+    } on Exception catch (e) {
       globals.printTrace('Failed to determine FlutterVersion after upgrade fast-forward: $e');
     }
     return alreadyUpToDate;
diff --git a/packages/flutter_tools/lib/src/commands/version.dart b/packages/flutter_tools/lib/src/commands/version.dart
index 4d715a9..b5fff30 100644
--- a/packages/flutter_tools/lib/src/commands/version.dart
+++ b/packages/flutter_tools/lib/src/commands/version.dart
@@ -116,8 +116,8 @@
         throwOnError: true,
         workingDirectory: Cache.flutterRoot,
       );
-    } catch (e) {
-      throwToolExit('Unable to checkout version branch for version $version.');
+    } on Exception catch (e) {
+      throwToolExit('Unable to checkout version branch for version $version: $e');
     }
 
     final FlutterVersion flutterVersion = FlutterVersion();
diff --git a/packages/flutter_tools/lib/src/dart/pub.dart b/packages/flutter_tools/lib/src/dart/pub.dart
index ff0ef4c..10ae1b9 100644
--- a/packages/flutter_tools/lib/src/dart/pub.dart
+++ b/packages/flutter_tools/lib/src/dart/pub.dart
@@ -180,7 +180,8 @@
           retry: true,
         );
         status.stop();
-      } catch (exception) {
+      // The exception is rethrown, so don't catch only Exceptions.
+      } catch (exception) { // ignore: avoid_catches_without_on_clauses
         status.cancel();
         rethrow;
       }
@@ -322,7 +323,7 @@
         globals.stdio.addStdoutStream(process.stdout),
         globals.stdio.addStderrStream(process.stderr),
       ]);
-    } catch (err, stack) {
+    } on Exception catch (err, stack) {
       globals.printTrace('Echoing stdout or stderr from the pub subprocess failed:');
       globals.printTrace('$err\n$stack');
     }
diff --git a/packages/flutter_tools/lib/src/desktop_device.dart b/packages/flutter_tools/lib/src/desktop_device.dart
index 9250f5d..fd3d0df 100644
--- a/packages/flutter_tools/lib/src/desktop_device.dart
+++ b/packages/flutter_tools/lib/src/desktop_device.dart
@@ -116,7 +116,7 @@
       final Uri observatoryUri = await observatoryDiscovery.uri;
       onAttached(package, buildMode, process);
       return LaunchResult.succeeded(observatoryUri: observatoryUri);
-    } catch (error) {
+    } on Exception catch (error) {
       globals.printError('Error waiting for a debug connection: $error');
       return LaunchResult.failed();
     } finally {
diff --git a/packages/flutter_tools/lib/src/devfs.dart b/packages/flutter_tools/lib/src/devfs.dart
index b985bff..3a8be95 100644
--- a/packages/flutter_tools/lib/src/devfs.dart
+++ b/packages/flutter_tools/lib/src/devfs.dart
@@ -238,7 +238,7 @@
     List<int> bytes;
     try {
       bytes = await content.contentsAsBytes();
-    } catch (e) {
+    } on Exception catch (e) {
       return e;
     }
     final String fileContents = base64.encode(bytes);
@@ -251,7 +251,7 @@
           'fileContents': fileContents,
         },
       );
-    } catch (error) {
+    } on Exception catch (error) {
       globals.printTrace('DevFS: Failed to write $deviceUri: $error');
     }
   }
@@ -319,7 +319,7 @@
             onError: (dynamic error) { globals.printTrace('error: $error'); },
             cancelOnError: true);
         break;
-      } catch (error, trace) {
+      } on Exception catch (error, trace) {
         if (!_completer.isCompleted) {
           globals.printTrace('Error writing "$deviceUri" to DevFS: $error');
           if (retry > 0) {
@@ -527,7 +527,7 @@
       } on SocketException catch (socketException, stackTrace) {
         globals.printTrace('DevFS sync failed. Lost connection to device: $socketException');
         throw DevFSException('Lost connection to device.', socketException, stackTrace);
-      } catch (exception, stackTrace) {
+      } on Exception catch (exception, stackTrace) {
         globals.printError('Could not update files on device: $exception');
         throw DevFSException('Sync failed', exception, stackTrace);
       }
diff --git a/packages/flutter_tools/lib/src/doctor.dart b/packages/flutter_tools/lib/src/doctor.dart
index 74fd16e..5342800 100644
--- a/packages/flutter_tools/lib/src/doctor.dart
+++ b/packages/flutter_tools/lib/src/doctor.dart
@@ -187,7 +187,7 @@
       ValidationResult result;
       try {
         result = await asyncGuard<ValidationResult>(() => validator.validate());
-      } catch (exception) {
+      } on Exception catch (exception) {
         // We're generating a summary, so drop the stack trace.
         result = ValidationResult.crash(exception);
       }
@@ -269,10 +269,10 @@
       ValidationResult result;
       try {
         result = await validatorTask.result;
-      } catch (exception, stackTrace) {
-        result = ValidationResult.crash(exception, stackTrace);
-      } finally {
         status.stop();
+      } on Exception catch (exception, stackTrace) {
+        result = ValidationResult.crash(exception, stackTrace);
+        status.cancel();
       }
 
       switch (result.type) {
@@ -426,7 +426,7 @@
       _currentSlowWarning = subValidator.validator.slowWarning;
       try {
         results.add(await subValidator.result);
-      } catch (exception, stackTrace) {
+      } on Exception catch (exception, stackTrace) {
         results.add(ValidationResult.crash(exception, stackTrace));
       }
     }
@@ -656,7 +656,7 @@
   const int kExpectedExitCode = 255;
   try {
     return processUtils.runSync(<String>[genSnapshotPath]).exitCode == kExpectedExitCode;
-  } catch (error) {
+  } on Exception {
     return false;
   }
 }
@@ -784,7 +784,7 @@
           String installPath;
           try {
             installPath = globals.fs.file(globals.fs.path.join(dir.path, 'system', '.home')).readAsStringSync();
-          } catch (e) {
+          } on Exception {
             // ignored
           }
           if (installPath != null && globals.fs.isDirectorySync(installPath)) {
diff --git a/packages/flutter_tools/lib/src/fuchsia/fuchsia_device.dart b/packages/flutter_tools/lib/src/fuchsia/fuchsia_device.dart
index 3efe09a..9dfb52f 100644
--- a/packages/flutter_tools/lib/src/fuchsia/fuchsia_device.dart
+++ b/packages/flutter_tools/lib/src/fuchsia/fuchsia_device.dart
@@ -271,7 +271,7 @@
         packageRepo.deleteSync(recursive: true);
       }
       packageRepo.createSync(recursive: true);
-    } catch (e) {
+    } on Exception catch (e) {
       globals.printError('Failed to create Fuchisa package repo directory '
                  'at ${packageRepo.path}: $e');
       return LaunchResult.failed();
@@ -384,7 +384,7 @@
       globals.printTrace("Removing the tool's package repo: at ${packageRepo.path}");
       try {
         packageRepo.deleteSync(recursive: true);
-      } catch (e) {
+      } on Exception catch (e) {
         globals.printError('Failed to remove Fuchsia package repo directory '
                    'at ${packageRepo.path}: $e.');
       }
@@ -467,9 +467,9 @@
             'Failed to delete screenshot.ppm from the device:\n$deleteResult'
           );
         }
-      } catch (_) {
+      } on Exception catch (e) {
         globals.printError(
-          'Failed to delete screenshot.ppm from the device'
+          'Failed to delete screenshot.ppm from the device: $e'
         );
       }
     }
diff --git a/packages/flutter_tools/lib/src/fuchsia/fuchsia_sdk.dart b/packages/flutter_tools/lib/src/fuchsia/fuchsia_sdk.dart
index 628e624..59fc738 100644
--- a/packages/flutter_tools/lib/src/fuchsia/fuchsia_sdk.dart
+++ b/packages/flutter_tools/lib/src/fuchsia/fuchsia_sdk.dart
@@ -92,7 +92,7 @@
             .transform(const LineSplitter()));
       });
       return controller.stream;
-    } catch (exception) {
+    } on Exception catch (exception) {
       globals.printTrace('$exception');
     }
     return const Stream<String>.empty();
diff --git a/packages/flutter_tools/lib/src/intellij/intellij.dart b/packages/flutter_tools/lib/src/intellij/intellij.dart
index 48a9a50..a976c0d 100644
--- a/packages/flutter_tools/lib/src/intellij/intellij.dart
+++ b/packages/flutter_tools/lib/src/intellij/intellij.dart
@@ -67,7 +67,7 @@
       final int start = content.indexOf(versionStartTag);
       final int end = content.indexOf('</version>', start);
       return content.substring(start + versionStartTag.length, end);
-    } catch (_) {
+    } on Exception {
       return null;
     }
   }
diff --git a/packages/flutter_tools/lib/src/ios/devices.dart b/packages/flutter_tools/lib/src/ios/devices.dart
index 6cdea04..3d30292 100644
--- a/packages/flutter_tools/lib/src/ios/devices.dart
+++ b/packages/flutter_tools/lib/src/ios/devices.dart
@@ -448,7 +448,7 @@
       }
     }
     return utf8.decode(out);
-  } catch (_) {
+  } on Exception {
     // Unable to decode line: return as-is.
     return line;
   }
diff --git a/packages/flutter_tools/lib/src/ios/simulators.dart b/packages/flutter_tools/lib/src/ios/simulators.dart
index d9f8fe3..44a688b 100644
--- a/packages/flutter_tools/lib/src/ios/simulators.dart
+++ b/packages/flutter_tools/lib/src/ios/simulators.dart
@@ -291,7 +291,7 @@
       final IOSApp iosApp = app;
       await SimControl.instance.install(id, iosApp.simulatorBundlePath);
       return true;
-    } catch (e) {
+    } on Exception {
       return false;
     }
   }
@@ -301,7 +301,7 @@
     try {
       await SimControl.instance.uninstall(id, app.id);
       return true;
-    } catch (e) {
+    } on Exception {
       return false;
     }
   }
@@ -395,7 +395,7 @@
       final String bundleIdentifier = globals.plistParser.getValueFromFile(plistPath, PlistParser.kCFBundleIdentifierKey);
 
       await SimControl.instance.launch(id, bundleIdentifier, args);
-    } catch (error) {
+    } on Exception catch (error) {
       globals.printError('$error');
       return LaunchResult.failed();
     }
@@ -411,7 +411,7 @@
     try {
       final Uri deviceUri = await observatoryDiscovery.uri;
       return LaunchResult.succeeded(observatoryUri: deviceUri);
-    } catch (error) {
+    } on Exception catch (error) {
       globals.printError('Error waiting for a debug connection: $error');
       return LaunchResult.failed();
     } finally {
diff --git a/packages/flutter_tools/lib/src/ios/xcodeproj.dart b/packages/flutter_tools/lib/src/ios/xcodeproj.dart
index 4cca408..25117a6 100644
--- a/packages/flutter_tools/lib/src/ios/xcodeproj.dart
+++ b/packages/flutter_tools/lib/src/ios/xcodeproj.dart
@@ -339,7 +339,7 @@
       );
       final String out = result.stdout.trim();
       return parseXcodeBuildSettings(out);
-    } catch(error) {
+    } on Exception catch (error) {
       if (error is ProcessException && error.toString().contains('timed out')) {
         BuildEvent('xcode-show-build-settings-timeout',
           command: showBuildSettingsCommand.join(' '),
diff --git a/packages/flutter_tools/lib/src/macos/xcode.dart b/packages/flutter_tools/lib/src/macos/xcode.dart
index 55d22dc..936a589 100644
--- a/packages/flutter_tools/lib/src/macos/xcode.dart
+++ b/packages/flutter_tools/lib/src/macos/xcode.dart
@@ -406,11 +406,15 @@
       final String architecture = deviceProperties['architecture'] as String;
       try {
         cpuArchitecture = getIOSArchForName(architecture);
-      } catch (error) {
-        // Fallback to default iOS architecture. Future-proof against a theoretical version
-        // of Xcode that changes this string to something slightly different like "ARM64".
+      } on Exception {
+        // Fallback to default iOS architecture. Future-proof against a
+        // theoretical version of Xcode that changes this string to something
+        // slightly different like "ARM64".
         cpuArchitecture ??= defaultIOSArchs.first;
-        _logger.printError('Unknown architecture $architecture, defaulting to ${getNameForDarwinArch(cpuArchitecture)}');
+        _logger.printError(
+          'Unknown architecture $architecture, defaulting to '
+          '${getNameForDarwinArch(cpuArchitecture)}',
+        );
       }
     }
     return cpuArchitecture;
diff --git a/packages/flutter_tools/lib/src/reporting/crash_reporting.dart b/packages/flutter_tools/lib/src/reporting/crash_reporting.dart
index 466ba63..1bffbf7 100644
--- a/packages/flutter_tools/lib/src/reporting/crash_reporting.dart
+++ b/packages/flutter_tools/lib/src/reporting/crash_reporting.dart
@@ -126,7 +126,9 @@
       } else {
         globals.printError('Failed to send crash report. Server responded with HTTP status code ${resp.statusCode}');
       }
-    } catch (sendError, sendStackTrace) {
+    // Catch all exceptions to print the message that makes clear that the
+    // crash logger crashed.
+    } catch (sendError, sendStackTrace) { // ignore: avoid_catches_without_on_clauses
       if (sendError is SocketException || sendError is HttpException) {
         globals.printError('Failed to send crash report due to a network error: $sendError');
       } else {
diff --git a/packages/flutter_tools/lib/src/reporting/events.dart b/packages/flutter_tools/lib/src/reporting/events.dart
index 3bf8139..4696550 100644
--- a/packages/flutter_tools/lib/src/reporting/events.dart
+++ b/packages/flutter_tools/lib/src/reporting/events.dart
@@ -195,7 +195,7 @@
         label: parameter,
         value: maxRss,
       );
-    } catch (error) {
+    } on Exception catch (error) {
       // If grabbing the maxRss fails for some reason, just don't send an event.
       globals.printTrace('Querying maxRss failed with error: $error');
     }
diff --git a/packages/flutter_tools/lib/src/reporting/github_template.dart b/packages/flutter_tools/lib/src/reporting/github_template.dart
index f607a5b..5d958b7 100644
--- a/packages/flutter_tools/lib/src/reporting/github_template.dart
+++ b/packages/flutter_tools/lib/src/reporting/github_template.dart
@@ -136,7 +136,7 @@
       } else {
         globals.printTrace('Failed to shorten GitHub template URL. Server responded with HTTP status code ${response.statusCode}');
       }
-    } catch (sendError) {
+    } on Exception catch (sendError) {
       globals.printTrace('Failed to shorten GitHub template URL: $sendError');
     }
 
diff --git a/packages/flutter_tools/lib/src/resident_runner.dart b/packages/flutter_tools/lib/src/resident_runner.dart
index d24e3c7..66d6622 100644
--- a/packages/flutter_tools/lib/src/resident_runner.dart
+++ b/packages/flutter_tools/lib/src/resident_runner.dart
@@ -873,7 +873,7 @@
           for (final FlutterView view in device.views) {
             await view.uiIsolate.flutterDebugAllowBanner(false);
           }
-        } catch (error) {
+        } on Exception catch (error) {
           status.cancel();
           globals.printError('Error communicating with Flutter on the device: $error');
           return;
@@ -887,7 +887,7 @@
             for (final FlutterView view in device.views) {
               await view.uiIsolate.flutterDebugAllowBanner(true);
             }
-          } catch (error) {
+          } on Exception catch (error) {
             status.cancel();
             globals.printError('Error communicating with Flutter on the device: $error');
             return;
@@ -899,7 +899,7 @@
       globals.printStatus(
         'Screenshot written to ${globals.fs.path.relative(outputFile.path)} (${sizeKB}kB).',
       );
-    } catch (error) {
+    } on Exception catch (error) {
       status.cancel();
       globals.printError('Error taking screenshot: $error');
     }
@@ -1301,7 +1301,8 @@
     try {
       lastReceivedCommand = command;
       await _commonTerminalInputHandler(command);
-    } catch (error, st) {
+    // Catch all exception since this is doing cleanup and rethrowing.
+    } catch (error, st) { // ignore: avoid_catches_without_on_clauses
       // Don't print stack traces for known error types.
       if (error is! ToolExit) {
         globals.printError('$error\n$st');
diff --git a/packages/flutter_tools/lib/src/run_cold.dart b/packages/flutter_tools/lib/src/run_cold.dart
index 6dbc7d6..49387c1 100644
--- a/packages/flutter_tools/lib/src/run_cold.dart
+++ b/packages/flutter_tools/lib/src/run_cold.dart
@@ -131,7 +131,7 @@
     _didAttach = true;
     try {
       await connectToServiceProtocol();
-    } catch (error) {
+    } on Exception catch (error) {
       globals.printError('Error connecting to the service protocol: $error');
       // https://github.com/flutter/flutter/issues/33050
       // TODO(blasten): Remove this check once https://issuetracker.google.com/issues/132325318 has been fixed.
diff --git a/packages/flutter_tools/lib/src/run_hot.dart b/packages/flutter_tools/lib/src/run_hot.dart
index 32f98a6..4c53ad6 100644
--- a/packages/flutter_tools/lib/src/run_hot.dart
+++ b/packages/flutter_tools/lib/src/run_hot.dart
@@ -186,7 +186,7 @@
         final Map<String, dynamic> firstReport = reports.first;
         await device.updateReloadStatus(validateReloadReport(firstReport, printErrors: false));
       }
-    } catch (error) {
+    } on Exception catch (error) {
       return OperationResult(1, error.toString());
     }
 
@@ -215,14 +215,25 @@
         compileExpression: _compileExpressionService,
         reloadMethod: reloadMethod,
       );
-    } catch (error) {
+    // Catches all exceptions, non-Exception objects are rethrown.
+    } catch (error) { // ignore: avoid_catches_without_on_clauses
+      if (error is! Exception && error is! String) {
+        rethrow;
+      }
       globals.printError('Error connecting to the service protocol: $error');
       // https://github.com/flutter/flutter/issues/33050
-      // TODO(blasten): Remove this check once https://issuetracker.google.com/issues/132325318 has been fixed.
+      // TODO(blasten): Remove this check once
+      // https://issuetracker.google.com/issues/132325318 has been fixed.
       if (await hasDeviceRunningAndroidQ(flutterDevices) &&
           error.toString().contains(kAndroidQHttpConnectionClosedExp)) {
-        globals.printStatus('🔨 If you are using an emulator running Android Q Beta, consider using an emulator running API level 29 or lower.');
-        globals.printStatus('Learn more about the status of this issue on https://issuetracker.google.com/issues/132325318.');
+        globals.printStatus(
+          '🔨 If you are using an emulator running Android Q Beta, '
+          'consider using an emulator running API level 29 or lower.',
+        );
+        globals.printStatus(
+          'Learn more about the status of this issue on '
+          'https://issuetracker.google.com/issues/132325318.',
+        );
       }
       return 2;
     }
@@ -242,7 +253,7 @@
           ),
         );
       }
-    } catch (error) {
+    } on Exception catch (error) {
       globals.printError('Error initializing DevFS: $error');
       return 3;
     }
@@ -872,7 +883,7 @@
         return OperationResult(errorCode, errorMessage);
       }
       return OperationResult(errorCode, '$errorMessage (error code: $errorCode)');
-    } catch (error, stackTrace) {
+    } on Exception catch (error, stackTrace) {
       globals.printTrace('Hot reload failed: $error\n$stackTrace');
       return OperationResult(1, '$error');
     }
@@ -936,7 +947,7 @@
         () async {
           try {
             await view.uiIsolate.flutterReassemble();
-          } catch (error) {
+          } on Exception catch (error) {
             failedReassemble = true;
             globals.printError('Reassembling ${view.uiIsolate.name} failed: $error');
             return;
diff --git a/packages/flutter_tools/lib/src/runner/flutter_command_runner.dart b/packages/flutter_tools/lib/src/runner/flutter_command_runner.dart
index 4ce44f3..8342289 100644
--- a/packages/flutter_tools/lib/src/runner/flutter_command_runner.dart
+++ b/packages/flutter_tools/lib/src/runner/flutter_command_runner.dart
@@ -8,6 +8,7 @@
 import 'package:args/command_runner.dart';
 import 'package:completion/completion.dart';
 import 'package:file/file.dart';
+import 'package:meta/meta.dart';
 
 import '../artifacts.dart';
 import '../base/common.dart';
@@ -189,7 +190,7 @@
       if (script.contains('flutter/examples/')) {
         return script.substring(0, script.indexOf('flutter/examples/') + 8);
       }
-    } catch (error) {
+    } on Exception catch (error) {
       // we don't have a logger at the time this is run
       // (which is why we don't use printTrace here)
       print(userMessages.runnerNoRoot('$error'));
@@ -421,6 +422,7 @@
     return EngineBuildPaths(targetEngine: engineBuildPath, hostEngine: engineHostBuildPath);
   }
 
+  @visibleForTesting
   static void initFlutterRoot() {
     Cache.flutterRoot ??= defaultFlutterRoot;
   }
diff --git a/packages/flutter_tools/lib/src/test/flutter_platform.dart b/packages/flutter_tools/lib/src/test/flutter_platform.dart
index 1e78e9e..025a455 100644
--- a/packages/flutter_tools/lib/src/test/flutter_platform.dart
+++ b/packages/flutter_tools/lib/src/test/flutter_platform.dart
@@ -313,7 +313,7 @@
       final RunnerSuiteController controller = deserializeSuite(path, platform,
         suiteConfig, const PluginEnvironment(), channel, message);
       return await controller.suite;
-    } catch (err) {
+    } on Exception catch (err) {
       /// Rethrow a less confusing error if it is a test incompatibility.
       if (err.toString().contains("type 'Declarer' is not a subtype of type 'Declarer'")) {
         throw UnsupportedError('Package incompatibility between flutter and test packages:\n'
@@ -667,7 +667,7 @@
           }
           break;
       }
-    } catch (error, stack) {
+    } on Exception catch (error, stack) {
       globals.printTrace('test $ourTestCount: error caught during test; ${controllerSinkClosed ? "reporting to console" : "sending to test framework"}');
       if (!controllerSinkClosed) {
         controller.sink.addError(error, stack);
@@ -681,7 +681,7 @@
       for (final Finalizer finalizer in finalizers.reversed) {
         try {
           await finalizer();
-        } catch (error, stack) {
+        } on Exception catch (error, stack) {
           globals.printTrace('test $ourTestCount: error while cleaning up; ${controllerSinkClosed ? "reporting to console" : "sending to test framework"}');
           if (!controllerSinkClosed) {
             controller.sink.addError(error, stack);
@@ -873,7 +873,7 @@
               if (reportObservatoryUri != null) {
                 reportObservatoryUri(uri);
               }
-            } catch (error) {
+            } on Exception catch (error) {
               globals.printError('Could not parse shell observatory port message: $error');
             }
           } else if (line != null) {
diff --git a/packages/flutter_tools/lib/src/test/flutter_web_platform.dart b/packages/flutter_tools/lib/src/test/flutter_web_platform.dart
index 30885f9..129679e 100644
--- a/packages/flutter_tools/lib/src/test/flutter_web_platform.dart
+++ b/packages/flutter_tools/lib/src/test/flutter_web_platform.dart
@@ -735,7 +735,8 @@
 
         _controllers.add(controller);
         return await controller.suite;
-      } catch (_) {
+      // Not limiting to catching Exception because the exception is rethrown.
+      } catch (_) { // ignore: avoid_catches_without_on_clauses
         closeIframe();
         rethrow;
       }
@@ -989,7 +990,7 @@
         try {
           bool success = await goldenFileComparator.compare(bytes, goldenKey);
           print(jsonEncode({'success': success}));
-        } catch (ex) {
+        } on Exception catch (ex) {
           print(jsonEncode({'success': false, 'message': '\$ex'}));
         }
       }
diff --git a/packages/flutter_tools/lib/src/tester/flutter_tester.dart b/packages/flutter_tools/lib/src/tester/flutter_tester.dart
index bd90c60..19cea0f 100644
--- a/packages/flutter_tools/lib/src/tester/flutter_tester.dart
+++ b/packages/flutter_tools/lib/src/tester/flutter_tester.dart
@@ -194,7 +194,7 @@
 
       final Uri observatoryUri = await observatoryDiscovery.uri;
       return LaunchResult.succeeded(observatoryUri: observatoryUri);
-    } catch (error) {
+    } on Exception catch (error) {
       globals.printError('Failed to launch $package: $error');
       return LaunchResult.failed();
     }
diff --git a/packages/flutter_tools/lib/src/tracing.dart b/packages/flutter_tools/lib/src/tracing.dart
index 020d068..25402b8 100644
--- a/packages/flutter_tools/lib/src/tracing.dart
+++ b/packages/flutter_tools/lib/src/tracing.dart
@@ -60,7 +60,8 @@
         if (!done) {
           await whenFirstFrameRendered.future;
         }
-      } catch (exception) {
+      // The exception is rethrown, so don't catch only Exceptions.
+      } catch (exception) { // ignore: avoid_catches_without_on_clauses
         status.cancel();
         rethrow;
       }
diff --git a/packages/flutter_tools/lib/src/version.dart b/packages/flutter_tools/lib/src/version.dart
index 8a87986..03ab5de 100644
--- a/packages/flutter_tools/lib/src/version.dart
+++ b/packages/flutter_tools/lib/src/version.dart
@@ -528,7 +528,7 @@
         } else {
           globals.printTrace('Warning: expected version stamp to be a Map but found: $jsonObject');
         }
-      } catch (error, stackTrace) {
+      } on Exception catch (error, stackTrace) {
         // Do not crash if JSON is malformed.
         globals.printTrace('${error.runtimeType}: $error\n$stackTrace');
       }
diff --git a/packages/flutter_tools/lib/src/vmservice.dart b/packages/flutter_tools/lib/src/vmservice.dart
index f18f802..db9f783 100644
--- a/packages/flutter_tools/lib/src/vmservice.dart
+++ b/packages/flutter_tools/lib/src/vmservice.dart
@@ -145,7 +145,7 @@
           return <String, String>{'type': 'Success'};
         } on rpc.RpcException {
           rethrow;
-        } catch (e, st) {
+        } on Exception catch (e, st) {
           throw rpc.RpcException(rpc_error_code.SERVER_ERROR,
               'Error during Sources Reload: $e\n$st');
         }
@@ -189,7 +189,7 @@
           return <String, String>{'type': 'Success'};
         } on rpc.RpcException {
           rethrow;
-        } catch (e, st) {
+        } on Exception catch (e, st) {
           throw rpc.RpcException(rpc_error_code.SERVER_ERROR,
               'Error during Sources Reload: $e\n$st');
         }
@@ -213,7 +213,7 @@
           return <String, String>{'type': 'Success'};
         } on rpc.RpcException {
           rethrow;
-        } catch (e, st) {
+        } on Exception catch (e, st) {
           throw rpc.RpcException(rpc_error_code.SERVER_ERROR,
               'Error during Hot Restart: $e\n$st');
         }
@@ -266,7 +266,7 @@
             'result': <String, dynamic> {'kernelBytes': kernelBytesBase64}};
         } on rpc.RpcException {
           rethrow;
-        } catch (e, st) {
+        } on Exception catch (e, st) {
           throw rpc.RpcException(rpc_error_code.SERVER_ERROR,
               'Error during expression compilation: $e\n$st');
         }
@@ -625,7 +625,8 @@
           updateFromMap(response);
           completer.complete(this);
         }
-      } catch (e, st) {
+      // Catches all exceptions to propagate to the completer.
+      } catch (e, st) { // ignore: avoid_catches_without_on_clauses
         completer.completeError(e, st);
       }
       _inProgressReload = null;
diff --git a/packages/flutter_tools/lib/src/web/chrome.dart b/packages/flutter_tools/lib/src/web/chrome.dart
index f285496..19166da 100644
--- a/packages/flutter_tools/lib/src/web/chrome.dart
+++ b/packages/flutter_tools/lib/src/web/chrome.dart
@@ -211,7 +211,7 @@
     if (!skipCheck) {
       try {
         await chrome.chromeConnection.getTabs();
-      } catch (e) {
+      } on Exception catch (e) {
         await chrome.close();
         throwToolExit(
             'Unable to connect to Chrome debug port: ${chrome.debugPort}\n $e');
@@ -235,7 +235,7 @@
       final HttpClientResponse response = await request.close();
       final List<dynamic> jsonObject = await json.fuse(utf8).decoder.bind(response).single as List<dynamic>;
       return base.resolve(jsonObject.first['devtoolsFrontendUrl'] as String);
-    } catch (_) {
+    } on Exception {
       // If we fail to talk to the remote debugger protocol, give up and return
       // the raw URL rather than crashing.
       return base;
diff --git a/packages/flutter_tools/lib/src/web/compile.dart b/packages/flutter_tools/lib/src/web/compile.dart
index 15a1f6e..e75471a 100644
--- a/packages/flutter_tools/lib/src/web/compile.dart
+++ b/packages/flutter_tools/lib/src/web/compile.dart
@@ -66,7 +66,7 @@
       }
       throwToolExit('Failed to compile application for the Web.');
     }
-  } catch (err) {
+  } on Exception catch (err) {
     throwToolExit(err.toString());
   } finally {
     status.stop();