Fix for FastUri.hashCode and hasAuthorizy (to fix ==).

pkg/analyzer/lib/src/util/fast_uri.dart

Index: pkg/analyzer/lib/src/util/fast_uri.dart
diff --git a/pkg/analyzer/lib/src/util/fast_uri.dart b/pkg/analyzer/lib/src/util/fast_uri.dart
index 4913dfab0817e0e83804d0b2abb80fb75dca8f23..ea4f8e87b92252a7d3ddbaaa48cae6835dd98271 100644
--- a/pkg/analyzer/lib/src/util/fast_uri.dart
+++ b/pkg/analyzer/lib/src/util/fast_uri.dart
@@ -22,6 +22,7 @@ class FastUri implements Uri {
   final int _cacheGeneration;
   final String _text;
   final String _scheme;
+  final bool _hasEmptyAuthority;
   final String _path;
 
   /**
@@ -36,8 +37,8 @@ class FastUri implements Uri {
 
   Uri _cachedFallbackUri;
 
-  FastUri._(this._cacheGeneration, this._text, this._scheme, this._path,
-      this._lastSlashIndex);
+  FastUri._(this._cacheGeneration, this._text, this._scheme,
+      this._hasEmptyAuthority, this._path, this._lastSlashIndex);
 
   @override
   String get authority => '';
@@ -52,7 +53,7 @@ class FastUri implements Uri {
   bool get hasAbsolutePath => path.startsWith('/');
 
   @override
-  bool get hasAuthority => false;
+  bool get hasAuthority => _hasEmptyAuthority;
 
   @override
   bool get hasEmptyPath => _path.isEmpty;
@@ -62,8 +63,19 @@ class FastUri implements Uri {
 
   @override
   int get hashCode {
-    _hashCode ??= (scheme.hashCode * 31 + path.hashCode) & 0x3FFFFFFF;
-    return _hashCode;
+    // This code is copied from the standard Uri implementation.

[Paul Berry, 2016/05/23 15:34:01]

Nit: Consider including a comment explaining why it's necessary to copy this
code from the standard Uri implementation, e.g.

"It is important that Uri and FastUri generate compatible hashCodes because Uri
and FastUri may be used as keys in the same map."

+    int combine(part, current) {
+      // The sum is truncated to 30 bits to make sure it fits into a Smi.
+      return (current * 31 + part.hashCode) & 0x3FFFFFFF;
+    }
+    return _hashCode ??= combine(
+        scheme,
+        combine(
+            userInfo,
+            combine(
+                host,
+                combine(port,
+                    combine(path, combine(query, combine(fragment, 1)))))));
   }
 
   @override
@@ -262,11 +274,16 @@ class FastUri implements Uri {
       }
     }
     String scheme = schemeEnd != null ? text.substring(0, schemeEnd) : '';
+    bool hasEmptyAuthority = false;
     String path = text.substring(pathStart);
     if (path.startsWith('//')) {
+      hasEmptyAuthority = true;
       path = path.substring(2);
+      if (!path.startsWith('/')) {
+        return null;
+      }
     }
-    return new FastUri._(
-        _currentCacheGeneration, text, scheme, path, lastSlashIndex);
+    return new FastUri._(_currentCacheGeneration, text, scheme,
+        hasEmptyAuthority, path, lastSlashIndex);
   }
 }