Add GetStartNodeExcludingAttributes helper.

src/Workspaces/CSharp/Portable/LanguageServices/CSharpSyntaxFactsService.cs

@@ -1795,8 +1795,7 @@ public bool IsOnTypeHeader(SyntaxNode root, int position)
                 return false;
             }
 
-            var start = typeDecl.AttributeLists.LastOrDefault()?.GetLastToken().GetNextToken().SpanStart ??
-                        typeDecl.SpanStart;
+            var start = GetStartOfNodeExcludingAttributes(typeDecl);
             var end = typeDecl.GetTypeParameterList()?.GetLastToken().FullSpan.End ??
                         typeDecl.Identifier.FullSpan.End;
 
@@ -1810,9 +1809,7 @@ public bool IsInPropertyDeclarationHeader(SyntaxNode node)
             {
                 return false;
             }
-
-            var start = propertyDeclaration.AttributeLists.LastOrDefault()?.GetLastToken().GetNextToken().SpanStart ??
-                        propertyDeclaration.SpanStart;
+            var start = GetStartOfNodeExcludingAttributes(propertyDeclaration);
             var end = propertyDeclaration.Identifier.FullSpan.End;
 
             return node.Span.Start >= start && node.Span.End <= end;
@@ -1826,8 +1823,7 @@ public bool IsInParameterHeader(SyntaxNode node)
                 return false;
             }
 
-            var start = propertyDeclaration.AttributeLists.LastOrDefault()?.GetLastToken().GetNextToken().SpanStart ??
-                        propertyDeclaration.SpanStart;
+            var start = GetStartOfNodeExcludingAttributes(propertyDeclaration);
             var end = propertyDeclaration.Identifier.FullSpan.End;
 
             return node.Span.Start >= start && node.Span.End <= end;
@@ -1973,6 +1969,6 @@ public void GetPartsOfCastExpression(SyntaxNode node, out SyntaxNode type, out S
 
         public SyntaxNode GetContainingParameter(SyntaxNode node) => node.GetAncestorOrThis<ParameterSyntax>();
 
-        public SyntaxList<SyntaxNode> GetAttributeLists(SyntaxNode node) => CSharpSyntaxGenerator.GetAttributeLists(node);
+        public override SyntaxList<SyntaxNode> GetAttributeLists(SyntaxNode node) => CSharpSyntaxGenerator.GetAttributeLists(node);
     }
 }

src/Workspaces/Core/Portable/LanguageServices/SyntaxFactsService/AbstractSyntaxFactsService.cs

@@ -487,5 +487,16 @@ public bool SpansPreprocessorDirective(IEnumerable<SyntaxToken> tokens)
 
         private bool SpansPreprocessorDirective(SyntaxTriviaList list)
             => list.Any(t => IsPreprocessorDirective(t));
+
+        protected int GetStartOfNodeExcludingAttributes(SyntaxNode node)
+        {
+            var attributeLists = GetAttributeLists(node);
+            var start = attributeLists.LastOrDefault()?.GetLastToken().GetNextToken().SpanStart ??
+                        node.SpanStart;
+
+            return start;
+        }
+
+        public abstract SyntaxList<SyntaxNode> GetAttributeLists(SyntaxNode node);
     }
 }

src/Workspaces/VisualBasic/Portable/LanguageServices/VisualBasicSyntaxFactsService.vb

@@ -1746,8 +1746,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
                 Return Nothing
             End If
 
-            Dim start = If(statement.AttributeLists.LastOrDefault()?.GetLastToken().GetNextToken().SpanStart,
-                           statement.SpanStart)
+            Dim start = GetStartOfNodeExcludingAttributes(statement)
             Dim _end = If(statement.TypeParameterList?.GetLastToken().FullSpan.End,
                           statement.Identifier.FullSpan.End)
 
@@ -1761,20 +1760,20 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
                 Return False
             End If
 
-            Dim start = If(propertyDeclaration.AttributeLists.LastOrDefault()?.GetLastToken().GetNextToken().SpanStart, propertyDeclaration.SpanStart)
+            Dim start = GetStartOfNodeExcludingAttributes(propertyDeclaration)
             Dim [end] = If(propertyDeclaration.AsClause?.FullSpan.[End], propertyDeclaration.Identifier.FullSpan.End)
             Return node.Span.Start >= start AndAlso node.Span.[End] <= [end]
         End Function
 
         Public Function IsInParameterHeader(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsInParameterHeader
-            Dim propertyDeclaration = node.GetAncestor(Of ParameterSyntax)()
+            Dim parameter = node.GetAncestor(Of ParameterSyntax)()
 
-            If propertyDeclaration Is Nothing Then
+            If parameter Is Nothing Then
                 Return False
             End If
 
-            Dim start = If(propertyDeclaration.AttributeLists.LastOrDefault()?.GetLastToken().GetNextToken().SpanStart, propertyDeclaration.SpanStart)
-            Dim [end] = If(propertyDeclaration.AsClause?.FullSpan.[End], propertyDeclaration.Identifier.FullSpan.End)
+            Dim start = GetStartOfNodeExcludingAttributes(parameter)
+            Dim [end] = If(parameter.AsClause?.FullSpan.[End], parameter.Identifier.FullSpan.End)
             Return node.Span.Start >= start AndAlso node.Span.[End] <= [end]
         End Function
 
@@ -1977,7 +1976,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
             Return node.GetAncestorOrThis(Of ParameterSyntax)
         End Function
 
-        Public Function GetAttributeLists(node As SyntaxNode) As SyntaxList(Of SyntaxNode) Implements ISyntaxFactsService.GetAttributeLists
+        Public Overrides Function GetAttributeLists(node As SyntaxNode) As SyntaxList(Of SyntaxNode) Implements ISyntaxFactsService.GetAttributeLists
             Return VisualBasicSyntaxGenerator.GetAttributeLists(node)
         End Function
     End Class