Ádd additional check for invalid character in property

src/Build.UnitTests/Scanner_Tests.cs

@@ -115,6 +115,25 @@ public void WhitespaceProperty()
             Assert.Equal("IllFormedPropertyWhitespaceInCondition", lexer.GetErrorResource());
         }
 
+        /// <summary>
+        /// Tests for invalid element in property
+        /// </summary>
+        [Fact]
+        public void IllFormedPropertyInvalidElement()
+        {
+            Scanner lexer = new Scanner("$(x\\)", ParserOptions.AllowProperties);
+            AdvanceToScannerError(lexer);
+            Assert.Equal("IllFormedPropertyInvalidElementInCondition", lexer.GetErrorResource());
+
+            lexer = new Scanner("$(x{)", ParserOptions.AllowProperties);
+            AdvanceToScannerError(lexer);
+            Assert.Equal("IllFormedPropertyInvalidElementInCondition", lexer.GetErrorResource());
+
+            lexer = new Scanner("$(x;)", ParserOptions.AllowProperties);
+            AdvanceToScannerError(lexer);
+            Assert.Equal("IllFormedPropertyInvalidElementInCondition", lexer.GetErrorResource());
+        }
+
         /// <summary>
         /// Tests the special errors for "@(" and "@x" and similar cases.
         /// </summary>

src/Build/Evaluation/Conditionals/Scanner.cs

@@ -283,12 +283,12 @@ private string ParsePropertyOrItemMetadata()
                 return null;
             }
 
-            var result = ScanForPropertyExpressionEnd(_expression, _parsePoint++, out int indexResult);
-            if (!result)
+            var errorMessage = ScanForPropertyExpressionEnd(_expression, _parsePoint++, out int indexResult);
+            if (!string.IsNullOrEmpty(errorMessage))
             {
                 _errorState = true;
                 _errorPosition = indexResult;
-                _errorResource = "IllFormedPropertyWhitespaceInCondition";
+                _errorResource = errorMessage;
                 _unexpectedlyFound = Convert.ToString(_expression[indexResult], CultureInfo.InvariantCulture);
                 return null;
             }
@@ -316,11 +316,12 @@ private string ParsePropertyOrItemMetadata()
         /// <param name="index">current index to start from</param>
         /// <param name="indexResult">If successful, the index corresponds to the end of the property expression.
         /// In case of scan failure, it is the error position index.</param>
-        /// <returns>result indicating whether or not the scan was successful.</returns>
-        private static bool ScanForPropertyExpressionEnd(string expression, int index, out int indexResult)
+        /// <returns>Empty string in case of success, specific error message otherwise</returns>
+        private static string ScanForPropertyExpressionEnd(string expression, int index, out int indexResult)
         {
             int nestLevel = 0;
-            bool whitespaceCheck = false;
+            bool propertyValue = false;
+            string errorMessage = string.Empty;
 
             unsafe
             {
@@ -332,17 +333,25 @@ private static bool ScanForPropertyExpressionEnd(string expression, int index, o
                         if (character == '(')
                         {
                             nestLevel++;
-                            whitespaceCheck = true;
+                            propertyValue = true;
                         }
                         else if (character == ')')
                         {
                             nestLevel--;
-                            whitespaceCheck = false;
+                            propertyValue = false;
                         }
-                        else if (whitespaceCheck && char.IsWhiteSpace(character))
+                        else if (propertyValue)
                         {
-                            indexResult = index;
-                            return false;
+                            if (char.IsWhiteSpace(character))
+                            {
+                                indexResult = index;
+                                return "IllFormedPropertyWhitespaceInCondition";
+                            }
+                            else if (!XmlUtilities.IsValidSubsequentElementNameCharacter(character))
+                            {
+                                indexResult = index;
+                                return "IllFormedPropertyInvalidElementInCondition";
+                            }
                         }
 
                         // We have reached the end of the parenthesis nesting
@@ -351,7 +360,7 @@ private static bool ScanForPropertyExpressionEnd(string expression, int index, o
                         if (nestLevel == 0)
                         {
                             indexResult = index;
-                            return true;
+                            return errorMessage;
                         }
                         else
                         {
@@ -361,7 +370,7 @@ private static bool ScanForPropertyExpressionEnd(string expression, int index, o
                 }
             }
             indexResult = index;
-            return true;
+            return errorMessage;
         }
 
         /// <summary>

src/Build/Resources/Strings.resx

@@ -482,6 +482,10 @@
     <value>MSB4151: Unexpected whitespace at position "{1}" of condition "{0}". Did you forget to remove a whitespace?</value>
     <comment>{StrBegin="MSB4151: "}</comment>
   </data>
+  <data name="IllFormedPropertyInvalidElementInCondition" xml:space="preserve">
+    <value>MSB4152: Unexpected invalid element at position "{1}" of condition "{0}".</value>
+    <comment>{StrBegin="MSB4152: "}</comment>
+  </data>
   <data name="IllFormedQuotedStringInCondition" xml:space="preserve">
     <value>MSB4101: Expected a closing quote after position {1} in condition "{0}".</value>
     <comment>{StrBegin="MSB4101: "}</comment>