Fix implementation of HasLeadingTrivia and HasTrailingTrivia for SyntaxNode,...

Fix implementation of HasLeadingTrivia and HasTrailingTrivia for SyntaxNode, SyntaxToken and SyntaxNodeOrToken.

The previous implementation was incorrect when zero-length trivia (elastic markers) were the only trivia. (changeset 1394442)

Src/Compilers/CSharp/Test/Syntax/Syntax/SyntaxNodeTests.cs

@@ -2775,5 +2775,109 @@ static void Main(string[] args)
             SyntaxTree BlankTree = null;
             Assert.Throws<ArgumentNullException>(() => FirstUsingClause.SyntaxTree.GetChangedSpans(BlankTree));
         }
+
+        [Fact]
+        public void TestTriviaExists()
+        {
+            // token constructed using factory w/o specifying trivia (should have zero-width elastic trivia)
+            var idToken = SyntaxFactory.Identifier("foo");
+            Assert.Equal(true, idToken.HasLeadingTrivia);
+            Assert.Equal(1, idToken.LeadingTrivia.Count);
+            Assert.Equal(0, idToken.LeadingTrivia.Span.Length); // zero-width elastic trivia
+            Assert.Equal(true, idToken.HasTrailingTrivia);
+            Assert.Equal(1, idToken.TrailingTrivia.Count);
+            Assert.Equal(0, idToken.TrailingTrivia.Span.Length); // zero-width elastic trivia
+
+            // token constructed by parser w/o trivia
+            idToken = SyntaxFactory.ParseToken("x");
+            Assert.Equal(false, idToken.HasLeadingTrivia);
+            Assert.Equal(0, idToken.LeadingTrivia.Count);
+            Assert.Equal(false, idToken.HasTrailingTrivia);
+            Assert.Equal(0, idToken.TrailingTrivia.Count);
+
+            // token constructed by parser with trivia
+            idToken = SyntaxFactory.ParseToken(" x  ");
+            Assert.Equal(true, idToken.HasLeadingTrivia);
+            Assert.Equal(1, idToken.LeadingTrivia.Count);
+            Assert.Equal(1, idToken.LeadingTrivia.Span.Length);
+            Assert.Equal(true, idToken.HasTrailingTrivia);
+            Assert.Equal(1, idToken.TrailingTrivia.Count);
+            Assert.Equal(2, idToken.TrailingTrivia.Span.Length);
+
+            // node constructed using factory w/o specifying trivia
+            SyntaxNode namedNode = SyntaxFactory.IdentifierName("foo");
+            Assert.Equal(true, namedNode.HasLeadingTrivia);
+            Assert.Equal(1, namedNode.GetLeadingTrivia().Count);
+            Assert.Equal(0, namedNode.GetLeadingTrivia().Span.Length);  // zero-width elastic trivia
+            Assert.Equal(true, namedNode.HasTrailingTrivia);
+            Assert.Equal(1, namedNode.GetTrailingTrivia().Count);
+            Assert.Equal(0, namedNode.GetTrailingTrivia().Span.Length);  // zero-width elastic trivia
+
+            // node constructed by parse w/o trivia
+            namedNode = SyntaxFactory.ParseExpression("foo");
+            Assert.Equal(false, namedNode.HasLeadingTrivia);
+            Assert.Equal(0, namedNode.GetLeadingTrivia().Count);
+            Assert.Equal(false, namedNode.HasTrailingTrivia);
+            Assert.Equal(0, namedNode.GetTrailingTrivia().Count);
+
+            // node constructed by parse with trivia
+            namedNode = SyntaxFactory.ParseExpression(" foo  ");
+            Assert.Equal(true, namedNode.HasLeadingTrivia);
+            Assert.Equal(1, namedNode.GetLeadingTrivia().Count);
+            Assert.Equal(1, namedNode.GetLeadingTrivia().Span.Length);
+            Assert.Equal(true, namedNode.HasTrailingTrivia);
+            Assert.Equal(1, namedNode.GetTrailingTrivia().Count);
+            Assert.Equal(2, namedNode.GetTrailingTrivia().Span.Length);
+
+            // nodeOrToken with token constructed from factory w/o specifying trivia
+            SyntaxNodeOrToken nodeOrToken = SyntaxFactory.Identifier("foo");
+            Assert.Equal(true, nodeOrToken.HasLeadingTrivia);
+            Assert.Equal(1, nodeOrToken.GetLeadingTrivia().Count);
+            Assert.Equal(0, nodeOrToken.GetLeadingTrivia().Span.Length); // zero-width elastic trivia
+            Assert.Equal(true, nodeOrToken.HasTrailingTrivia);
+            Assert.Equal(1, nodeOrToken.GetTrailingTrivia().Count);
+            Assert.Equal(0, nodeOrToken.GetTrailingTrivia().Span.Length); // zero-width elastic trivia
+
+            // nodeOrToken with node constructed from factory w/o specifying trivia
+            nodeOrToken = SyntaxFactory.IdentifierName("foo");
+            Assert.Equal(true, nodeOrToken.HasLeadingTrivia);
+            Assert.Equal(1, nodeOrToken.GetLeadingTrivia().Count);
+            Assert.Equal(0, nodeOrToken.GetLeadingTrivia().Span.Length); // zero-width elastic trivia
+            Assert.Equal(true, nodeOrToken.HasTrailingTrivia);
+            Assert.Equal(1, nodeOrToken.GetTrailingTrivia().Count);
+            Assert.Equal(0, nodeOrToken.GetTrailingTrivia().Span.Length); // zero-width elastic trivia
+
+            // nodeOrToken with token parsed from factory w/o trivia
+            nodeOrToken = SyntaxFactory.ParseToken("foo");
+            Assert.Equal(false, nodeOrToken.HasLeadingTrivia);
+            Assert.Equal(0, nodeOrToken.GetLeadingTrivia().Count);
+            Assert.Equal(false, nodeOrToken.HasTrailingTrivia);
+            Assert.Equal(0, nodeOrToken.GetTrailingTrivia().Count);
+
+            // nodeOrToken with node parsed from factory w/o trivia
+            nodeOrToken = SyntaxFactory.ParseExpression("foo");
+            Assert.Equal(false, nodeOrToken.HasLeadingTrivia);
+            Assert.Equal(0, nodeOrToken.GetLeadingTrivia().Count);
+            Assert.Equal(false, nodeOrToken.HasTrailingTrivia);
+            Assert.Equal(0, nodeOrToken.GetTrailingTrivia().Count);
+
+            // nodeOrToken with token parsed from factory with trivia
+            nodeOrToken = SyntaxFactory.ParseToken(" foo  ");
+            Assert.Equal(true, nodeOrToken.HasLeadingTrivia);
+            Assert.Equal(1, nodeOrToken.GetLeadingTrivia().Count);
+            Assert.Equal(1, nodeOrToken.GetLeadingTrivia().Span.Length); // zero-width elastic trivia
+            Assert.Equal(true, nodeOrToken.HasTrailingTrivia);
+            Assert.Equal(1, nodeOrToken.GetTrailingTrivia().Count);
+            Assert.Equal(2, nodeOrToken.GetTrailingTrivia().Span.Length); // zero-width elastic trivia
+
+            // nodeOrToken with node parsed from factory with trivia
+            nodeOrToken = SyntaxFactory.ParseExpression(" foo  ");
+            Assert.Equal(true, nodeOrToken.HasLeadingTrivia);
+            Assert.Equal(1, nodeOrToken.GetLeadingTrivia().Count);
+            Assert.Equal(1, nodeOrToken.GetLeadingTrivia().Span.Length); // zero-width elastic trivia
+            Assert.Equal(true, nodeOrToken.HasTrailingTrivia);
+            Assert.Equal(1, nodeOrToken.GetTrailingTrivia().Count);
+            Assert.Equal(2, nodeOrToken.GetTrailingTrivia().Span.Length); // zero-width elastic trivia
+        }
     }
 }

Src/Compilers/Core/Portable/Syntax/SyntaxNode.cs

@@ -513,7 +513,7 @@ public bool HasLeadingTrivia
         {
             get
             {
-                return this.Green.HasLeadingTrivia;
+                return this.GetLeadingTrivia().Count > 0;
             }
         }
 
@@ -524,7 +524,7 @@ public bool HasTrailingTrivia
         {
             get
             {
-                return this.Green.HasTrailingTrivia;
+                return this.GetTrailingTrivia().Count > 0;
             }
         }
 

Src/Compilers/Core/Portable/Syntax/SyntaxNodeOrToken.cs

@@ -402,17 +402,7 @@ public bool HasLeadingTrivia
         {
             get
             {
-                if (this.token != null)
-                {
-                    return this.token.HasLeadingTrivia;
-                }
-
-                if (this.nodeOrParent != null)
-                {
-                    return this.nodeOrParent.HasLeadingTrivia;
-                }
-
-                return false;
+                return this.GetLeadingTrivia().Count > 0;
             }
         }
 
@@ -442,17 +432,7 @@ public bool HasTrailingTrivia
         {
             get
             {
-                if (this.token != null)
-                {
-                    return this.token.HasTrailingTrivia;
-                }
-
-                if (this.nodeOrParent != null)
-                {
-                    return this.nodeOrParent.HasTrailingTrivia;
-                }
-
-                return false;
+                return this.GetTrailingTrivia().Count > 0;
             }
         }
 

Src/Compilers/Core/Portable/Syntax/SyntaxToken.cs

@@ -243,7 +243,7 @@ internal void WriteTo(System.IO.TextWriter writer, bool leading, bool trailing)
         /// </summary>
         public bool HasLeadingTrivia
         {
-            get { return token != null && token.GetLeadingTriviaCore() != null; }
+            get { return this.LeadingTrivia.Count > 0; }
         }
 
         /// <summary>
@@ -251,7 +251,7 @@ public bool HasLeadingTrivia
         /// </summary>
         public bool HasTrailingTrivia
         {
-            get { return token != null && token.GetTrailingTriviaCore() != null; }
+            get { return this.TrailingTrivia.Count > 0; }
         }
 
         /// <summary>