Fix pipe escaping.

pkg/analyzer_cli/lib/src/error_formatter.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library analyzer_cli.src.error_formatter;
 
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/error.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer_cli/src/options.dart';
@@ skipping 87 matching lines @@
     } else {
       out.writeln("No issues found");
     }
   }
 }
 
 /// Helper for formatting [AnalysisError]s.
 /// The two format options are a user consumable format and a machine consumable
 /// format.
 class ErrorFormatter {
+  static final int _pipeCodeUnit = '|'.codeUnitAt(0);
+  static final int _slashCodeUnit = '\\'.codeUnitAt(0);
+
   final StringSink out;
   final CommandLineOptions options;
   final AnalysisStats stats;
+
   final _SeverityProcessor processSeverity;
 
   ErrorFormatter(this.out, this.options, this.stats,
       [this.processSeverity = _identity]);
 
   /// Compute the severity for this [error] or `null` if this error should be
   /// filtered.
   ErrorSeverity computeSeverity(AnalysisError error) =>
       processSeverity(error)?.severity;
 
@@ skipping 39 matching lines @@
         }
       }
 
       // [warning] 'foo' is not a... (/Users/.../tmp/foo.dart, line 1, col 2)
       out.write('[$errorType] ${error.message} ');
       out.write('(${source.fullName}');
       out.write(', line ${location.lineNumber}, col ${location.columnNumber})');
     }
     out.writeln();
   }
-
   void formatErrors(List<AnalysisErrorInfo> errorInfos) {
     stats.unfilteredCount += errorInfos.length;
 
     var errors = new List<AnalysisError>();
     var errorToLine = new Map<AnalysisError, LineInfo>();
     for (AnalysisErrorInfo errorInfo in errorInfos) {
       for (AnalysisError error in errorInfo.errors) {
         if (computeSeverity(error) != null) {
           errors.add(error);
           errorToLine[error] = errorInfo.lineInfo;
@@ skipping 35 matching lines @@
       } else if (error.errorCode.type == ErrorType.HINT) {
         stats.hintCount++;
       } else if (error.errorCode.type == ErrorType.LINT) {
         stats.lintCount++;
       }
       formatError(errorToLine, error);
     }
   }
 
   static String escapePipe(String input) {
-    var result = new StringBuffer();
-    for (var c in input.codeUnits) {
-      if (c == '\\' || c == '|') {
+    StringBuffer result = new StringBuffer();
+    for (int c in input.codeUnits) {
+      if (c == _slashCodeUnit || c == _pipeCodeUnit) {
         result.write('\\');
       }
       result.writeCharCode(c);
     }
     return result.toString();
   }
 }
 
 /// A severity with awareness of whether it was overridden by a processor.
 class ProcessedSeverity {
   ErrorSeverity severity;
   bool overridden;
   ProcessedSeverity(this.severity, [this.overridden = false]);
 }