**** Merged r49131 from MCS ****
[mono.git] / mcs / gmcs / cs-tokenizer.cs
index bd038f7562c1c39fdbc1671e11f03fd1d52aa5b8..99f73b8270cf1a4767d83983274cd8d2812752fc 100644 (file)
@@ -32,17 +32,21 @@ namespace Mono.CSharp
        public class Tokenizer : yyParser.yyInput
        {
                SeekableStreamReader reader;
-               public SourceFile ref_name;
-               public SourceFile file_name;
-               public int ref_line = 1;
-               public int line = 1;
-               public int col = 1;
-               public int current_token;
+               SourceFile ref_name;
+               SourceFile file_name;
+               int ref_line = 1;
+               int line = 1;
+               int col = 0;
+               int previous_col;
+               int current_token;
                bool handle_get_set = false;
                bool handle_remove_add = false;
                bool handle_assembly = false;
                bool handle_constraints = false;
                bool handle_typeof = false;
+               Location current_location;
+               Location current_comment_location = Location.Null;
+               ArrayList escapedIdentifiers = new ArrayList ();
 
                //
                // XML documentation buffer. The save point is used to divide
@@ -173,16 +177,25 @@ namespace Mono.CSharp
                        set {
                                if (value == XmlCommentState.Allowed) {
                                        check_incorrect_doc_comment ();
-                                       consume_doc_comment ();
+                                       reset_doc_comment ();
                                }
                                xmlDocState = value;
                        }
                }
 
+               public bool IsEscapedIdentifier (Location loc)
+               {
+                       foreach (LocatedToken lt in escapedIdentifiers)
+                               if (lt.Location.Equals (loc))
+                                       return true;
+                       return false;
+               }
+
                //
                // Class variables
                // 
                static CharArrayHashtable[] keywords;
+               static Hashtable keywordStrings = new Hashtable ();
                static NumberStyles styles;
                static NumberFormatInfo csharp_format_info;
                
@@ -215,7 +228,7 @@ namespace Mono.CSharp
 
                static CharArrayHashtable [] identifiers = new CharArrayHashtable [max_id_size + 1];
 
-               const int max_number_size = 128;
+               const int max_number_size = 512;
                static char [] number_builder = new char [max_number_size];
                static int number_pos;
                
@@ -243,6 +256,7 @@ namespace Mono.CSharp
                }
 
                static void AddKeyword (string kw, int token) {
+                       keywordStrings.Add (kw, kw);
                        if (keywords [kw.Length] == null) {
                                keywords [kw.Length] = new CharArrayHashtable (kw.Length);
                        }
@@ -382,9 +396,7 @@ namespace Mono.CSharp
                }
 
                public Location Location {
-                       get {
-                               return new Location (ref_line);
-                       }
+                       get { return current_location; }
                }
 
                void define (string def)
@@ -417,11 +429,7 @@ namespace Mono.CSharp
                        // FIXME: This could be `Location.Push' but we have to
                        // find out why the MS compiler allows this
                        //
-                       Mono.CSharp.Location.Push (file);
-               }
-
-               public static void Cleanup () {
-                       identifiers = null;
+                       Mono.CSharp.Location.Push (file, 0);
                }
 
                static bool is_identifier_start_character (char c)
@@ -433,12 +441,17 @@ namespace Mono.CSharp
                {
                        return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || c == '_' || (c >= '0' && c <= '9') || Char.IsLetter (c);
                }
-               
+
+               public static bool IsKeyword (string s)
+               {
+                       return keywordStrings [s] != null;
+               }
+
                public static bool IsValidIdentifier (string s)
                {
                        if (s == null || s.Length == 0)
                                return false;
-                       
+
                        if (!is_identifier_start_character (s [0]))
                                return false;
                        
@@ -518,7 +531,6 @@ namespace Mono.CSharp
                        return false;
                }
 
-               bool parsing_less_than = false;
                int parsing_generic_less_than = 0;
 
                int is_punct (char c, ref bool doread)
@@ -530,8 +542,10 @@ namespace Mono.CSharp
 
                        switch (c){
                        case '{':
+                               val = Location;
                                return Token.OPEN_BRACE;
                        case '}':
+                               val = Location;
                                return Token.CLOSE_BRACE;
                        case '[':
                                // To block doccomment inside attribute declaration.
@@ -550,8 +564,13 @@ namespace Mono.CSharp
 
                                // Save current position and parse next token.
                                int old = reader.Position;
+                               int old_ref_line = ref_line;
+                               int old_col = col;
+
                                int new_token = token ();
                                reader.Position = old;
+                               ref_line = old_ref_line;
+                               col = old_col;
                                putback_char = -1;
 
                                if (new_token == Token.OPEN_PARENS)
@@ -566,11 +585,11 @@ namespace Mono.CSharp
 
                        case ',':
                                return Token.COMMA;
-                       case ':':
-                               return Token.COLON;
                        case ';':
+                               val = Location;
                                return Token.SEMICOLON;
                        case '~':
+                               val = Location;
                                return Token.TILDE;
                        case '?':
                                return Token.INTERR;
@@ -644,24 +663,32 @@ namespace Mono.CSharp
                        d = peekChar ();
                        if (c == '+'){
                                
-                               if (d == '+')
+                               if (d == '+') {
+                                       val = Location;
                                        t = Token.OP_INC;
+                               }
                                else if (d == '=')
                                        t = Token.OP_ADD_ASSIGN;
-                               else
+                               else {
+                                       val = Location;
                                        return Token.PLUS;
+                               }
                                doread = true;
                                return t;
                        }
                        if (c == '-'){
-                               if (d == '-')
+                               if (d == '-') {
+                                       val = Location;
                                        t = Token.OP_DEC;
+                               }
                                else if (d == '=')
                                        t = Token.OP_SUB_ASSIGN;
                                else if (d == '>')
                                        t = Token.OP_PTR;
-                               else
+                               else {
+                                       val = Location;
                                        return Token.MINUS;
+                               }
                                doread = true;
                                return t;
                        }
@@ -671,6 +698,7 @@ namespace Mono.CSharp
                                        doread = true;
                                        return Token.OP_NE;
                                }
+                               val = Location;
                                return Token.BANG;
                        }
 
@@ -690,6 +718,7 @@ namespace Mono.CSharp
                                        doread = true;
                                        return Token.OP_AND_ASSIGN;
                                }
+                               val = Location;
                                return Token.BITWISE_AND;
                        }
 
@@ -709,6 +738,7 @@ namespace Mono.CSharp
                                        doread = true;
                                        return Token.OP_MULT_ASSIGN;
                                }
+                               val = Location;
                                return Token.STAR;
                        }
 
@@ -736,6 +766,15 @@ namespace Mono.CSharp
                                return Token.CARRET;
                        }
 
+                       if (c == ':'){
+                               if (d == ':'){
+                                       doread = true;
+                                       return Token.DOUBLE_COLON;
+                               }
+                               val = Location;
+                               return Token.COLON;
+                       }
+
                        return Token.ERROR;
                }
 
@@ -812,14 +851,7 @@ namespace Mono.CSharp
                {
                        return (e >= '0' && e <= '9') || (e >= 'A' && e <= 'F') || (e >= 'a' && e <= 'f');
                }
-               
-               void hex_digits (int c)
-               {
-                       if (c != -1)
-                               number_builder [number_pos++] = (char) c;
-                       
-               }
-               
+                               
                int real_type_suffix (int c)
                {
                        int t;
@@ -964,6 +996,7 @@ namespace Mono.CSharp
                int adjust_real (int t)
                {
                        string s = new String (number_builder, 0, number_pos);
+                       const string error_details = "Floating-point constant is outside the range of type `{0}'";
 
                        switch (t){
                        case Token.LITERAL_DECIMAL:
@@ -971,8 +1004,7 @@ namespace Mono.CSharp
                                        val = System.Decimal.Parse (s, styles, csharp_format_info);
                                } catch (OverflowException) {
                                        val = 0m;     
-                                       error_details = "Floating-point constant is outside the range of the type 'decimal'";
-                                       Report.Error (594, Location, error_details);
+                                       Report.Error (594, Location, error_details, "decimal");
                                }
                                break;
                        case Token.LITERAL_FLOAT:
@@ -980,8 +1012,7 @@ namespace Mono.CSharp
                                        val = (float) System.Double.Parse (s, styles, csharp_format_info);
                                } catch (OverflowException) {
                                        val = 0.0f;     
-                                       error_details = "Floating-point constant is outside the range of the type 'float'";
-                                       Report.Error (594, Location, error_details);
+                                       Report.Error (594, Location, error_details, "float");
                                }
                                break;
                                
@@ -992,8 +1023,7 @@ namespace Mono.CSharp
                                        val = System.Double.Parse (s, styles, csharp_format_info);
                                } catch (OverflowException) {
                                        val = 0.0;     
-                                       error_details = "Floating-point constant is outside the range of the type 'double'";
-                                       Report.Error (594, Location, error_details);
+                                       Report.Error (594, Location, error_details, "double");
                                }
                                break;
                        }
@@ -1198,7 +1228,7 @@ namespace Mono.CSharp
                                        goto default;
                                return v;
                        default:
-                               Report.Error (1009, Location, "Unrecognized escape sequence in " + (char)d);
+                               Report.Error (1009, Location, "Unrecognized escape sequence `\\{0}'", (char)d);
                                return d;
                        }
                        getChar ();
@@ -1207,13 +1237,22 @@ namespace Mono.CSharp
 
                int getChar ()
                {
-                       if (putback_char != -1){
-                               int x = putback_char;
+                       int x;
+                       if (putback_char != -1) {
+                               x = putback_char;
                                putback_char = -1;
-
-                               return x;
                        }
-                       return reader.Read ();
+                       else
+                               x = reader.Read ();
+                       if (x == '\n') {
+                               line++;
+                               ref_line++;
+                               previous_col = col;
+                               col = 0;
+                       }
+                       else
+                               col++;
+                       return x;
                }
 
                int peekChar ()
@@ -1240,6 +1279,14 @@ namespace Mono.CSharp
                                Console.WriteLine ("Current [{0}] putting back [{1}]  ", putback_char, c);
                                throw new Exception ("This should not happen putback on putback");
                        }
+                       if (c == '\n' || col == 0) {
+                               // It won't happen though.
+                               line--;
+                               ref_line--;
+                               col = previous_col;
+                       }
+                       else
+                               col--;
                        putback_char = c;
                }
 
@@ -1349,22 +1396,19 @@ namespace Mono.CSharp
                        cmd = static_cmd_arg.ToString ();
 
                        if (c == '\n'){
-                               line++;
-                               ref_line++;
                                return;
-                       } else if (c == '\r')
-                               col = 0;
+                       }
 
                        // skip over white space
                        while ((c = getChar ()) != -1 && (c != '\n') && ((c == '\r') || (c == ' ') || (c == '\t')))
                                ;
 
                        if (c == '\n'){
-                               line++;
-                               ref_line++;
                                return;
                        } else if (c == '\r'){
-                               col = 0;
+                               return;
+                       } else if (c == -1){
+                               arg = "";
                                return;
                        }
                        
@@ -1375,11 +1419,6 @@ namespace Mono.CSharp
                                static_cmd_arg.Append ((char) c);
                        }
 
-                       if (c == '\n'){
-                               line++;
-                               ref_line++;
-                       } else if (c == '\r')
-                               col = 0;
                        arg = static_cmd_arg.ToString ().Trim ();
                }
 
@@ -1394,7 +1433,7 @@ namespace Mono.CSharp
                        if (arg == "default"){
                                ref_line = line;
                                ref_name = file_name;
-                               Location.Push (ref_name);
+                               Location.Push (ref_name, line);
                                return true;
                        } else if (arg == "hidden"){
                                //
@@ -1416,7 +1455,7 @@ namespace Mono.CSharp
                                        ref_name = Location.LookupFile (name);
                                        file_name.HasLineDirective = true;
                                        ref_name.HasLineDirective = true;
-                                       Location.Push (ref_name);
+                                       Location.Push (ref_name, ref_line);
                                } else {
                                        ref_line = System.Int32.Parse (arg);
                                }
@@ -1470,21 +1509,22 @@ namespace Mono.CSharp
                /// </summary>
                void PreProcessPragma (string arg)
                {
-                       const string disable = "warning disable";
-                       const string restore = "warning restore";
+                       const string warning = "warning";
+                       const string w_disable = "warning disable";
+                       const string w_restore = "warning restore";
 
-                       if (arg == disable) {
+                       if (arg == w_disable) {
                                Report.RegisterWarningRegion (Location).WarningDisable (line);
                                return;
                        }
 
-                       if (arg == restore) {
+                       if (arg == w_restore) {
                                Report.RegisterWarningRegion (Location).WarningEnable (line);
                                return;
                        }
 
-                       if (arg.StartsWith (disable)) {
-                               int[] codes = ParseNumbers (arg.Substring (disable.Length));
+                       if (arg.StartsWith (w_disable)) {
+                               int[] codes = ParseNumbers (arg.Substring (w_disable.Length));
                                foreach (int code in codes) {
                                        if (code != 0)
                                                Report.RegisterWarningRegion (Location).WarningDisable (Location, code);
@@ -1492,15 +1532,23 @@ namespace Mono.CSharp
                                return;
                        }
 
-                       if (arg.StartsWith (restore)) {
-                               int[] codes = ParseNumbers (arg.Substring (restore.Length));
+                       if (arg.StartsWith (w_restore)) {
+                               int[] codes = ParseNumbers (arg.Substring (w_restore.Length));
+                               Hashtable w_table = Report.warning_ignore_table;
                                foreach (int code in codes) {
+                                       if (w_table != null && w_table.Contains (code))
+                                               Report.Warning (1635, 1, Location, "Cannot restore warning 'CS{0:0000}' because it was disabled globally", code);
                                        Report.RegisterWarningRegion (Location).WarningEnable (Location, code);
                                }
                                return;
                        }
 
-                       return;
+                       if (arg.StartsWith (warning)) {
+                               Report.Warning (1634, 1, Location, "Expected disable or restore");
+                               return;
+                       }
+
+                       Report.Warning (1633, 1, Location, "Unrecognized #pragma directive");
                }
 
                int[] ParseNumbers (string text)
@@ -1683,7 +1731,7 @@ namespace Mono.CSharp
                
                void Error_InvalidDirective ()
                {
-                       Report.Error (1517, Location, "Invalid pre-processor directive");
+                       Report.Error (1517, Location, "Invalid preprocessor directive");
                }
 
                void Error_UnexpectedDirective (string extra)
@@ -1695,9 +1743,8 @@ namespace Mono.CSharp
 
                void Error_TokensSeen ()
                {
-                       Report.Error (
-                               1032, Location,
-                               "Cannot define or undefine pre-processor symbols after a token in the file");
+                       Report.Error (1032, Location,
+                               "Cannot define or undefine preprocessor symbols after first token in file");
                }
                
                //
@@ -1710,6 +1757,8 @@ namespace Mono.CSharp
                        string cmd, arg;
                        bool region_directive = false;
 
+                       current_location = new Location (ref_line, Col);
+
                        get_cmd_arg (out cmd, out arg);
 
                        // Eat any trailing whitespaces and single-line comments
@@ -1734,7 +1783,7 @@ namespace Mono.CSharp
                                if (!PreProcessLine (arg))
                                        Report.Error (
                                                1576, Location,
-                                               "Argument to #line directive is missing or invalid");
+                                               "The line number specified for #line directive is missing or invalid");
                                return caller_is_taking;
 
                        case "region":
@@ -1785,10 +1834,14 @@ namespace Mono.CSharp
                                        int pop = (int) ifstack.Pop ();
                                        
                                        if (region_directive && ((pop & REGION) == 0))
-                                               Report.Error (1027, Location, "#endif directive expected");
+                                               Report.Error (1027, Location, "Expected `#endif' directive");
                                        else if (!region_directive && ((pop & REGION) != 0))
                                                Report.Error (1038, Location, "#endregion directive expected");
                                        
+                                       if (!region_directive && arg.Length != 0) {
+                                               Report.Error (1025, Location, "Single-line comment or end-of-line expected");
+                                       }
+                                       
                                        if (ifstack.Count == 0)
                                                return true;
                                        else {
@@ -1895,11 +1948,11 @@ namespace Mono.CSharp
                                return true;
 
                        case "warning":
-                               Report.Warning (1030, Location, "#warning: '{0}'", arg);
+                               Report.Warning (1030, Location, "#warning: `{0}'", arg);
                                return true;
                        }
 
-                       Report.Error (1024, Location, "Preprocessor directive expected (got: " + cmd + ")");
+                       Report.Error (1024, Location, "Wrong preprocessor directive");
                        return true;
 
                }
@@ -1924,11 +1977,7 @@ namespace Mono.CSharp
                                if (c == '\n'){
                                        if (!quoted)
                                                Report.Error (1010, Location, "Newline in constant");
-                                       line++;
-                                       ref_line++;
-                                       col = 0;
-                               } else
-                                       col++;
+                               }
 
                                if (!quoted){
                                        c = escape (c);
@@ -1959,21 +2008,26 @@ namespace Mono.CSharp
                                // Save current position and parse next token.
                                int old = reader.Position;
                                int old_putback = putback_char;
+                               int old_ref_line = ref_line;
+                               int old_col = col;
 
                                putback_char = -1;
 
                                int next_token = token ();
                                bool ok = (next_token == Token.CLASS) ||
                                        (next_token == Token.STRUCT) ||
-                                       (next_token == Token.INTERFACE);
+                                       (next_token == Token.INTERFACE) ||
+                                       (next_token == Token.ENUM); // "partial" is a keyword in 'partial enum', even though it's not valid
 
                                reader.Position = old;
+                               ref_line = old_ref_line;
+                               col = old_col;
                                putback_char = old_putback;
 
                                if (ok)
                                        return res;
                                else {
-                                       val = "partial";
+                                       val = new LocatedToken (Location, "partial");
                                        return Token.IDENTIFIER;
                                }
                        }
@@ -1984,11 +2038,13 @@ namespace Mono.CSharp
                private int consume_identifier (int s, bool quoted) 
                {
                        int pos = 1;
-                       int c;
+                       int c = -1;
                        
                        id_builder [0] = (char) s;
                                        
-                       while ((c = reader.Read ()) != -1) {
+                       current_location = new Location (ref_line, Col);
+
+                       while ((c = getChar ()) != -1) {
                                if (is_identifier_part_character ((char) c)){
                                        if (pos == max_id_size){
                                                Report.Error (645, Location, "Identifier too long (limit is 512 chars)");
@@ -1996,10 +2052,10 @@ namespace Mono.CSharp
                                        }
                                        
                                        id_builder [pos++] = (char) c;
-                                       putback_char = -1;
-                                       col++;
+//                                     putback_char = -1;
                                } else {
-                                       putback_char = c;
+//                                     putback_char = c;
+                                       putback (c);
                                        break;
                                }
                        }
@@ -2010,8 +2066,10 @@ namespace Mono.CSharp
                        //
                        if (!quoted && (s >= 'a' || s == '_')){
                                int keyword = GetKeyword (id_builder, pos);
-                               if (keyword != -1)
+                               if (keyword != -1) {
+                                       val = Location;
                                return keyword;
+                               }
                        }
 
                        //
@@ -2022,6 +2080,9 @@ namespace Mono.CSharp
                        if (identifiers [pos] != null) {
                                val = identifiers [pos][id_builder];
                                if (val != null) {
+                                       val = new LocatedToken (Location, (string) val);
+                                       if (quoted)
+                                               escapedIdentifiers.Add (val);
                                        return Token.IDENTIFIER;
                                }
                        }
@@ -2029,12 +2090,19 @@ namespace Mono.CSharp
                                identifiers [pos] = new CharArrayHashtable (pos);
 
                        val = new String (id_builder, 0, pos);
+                       if (RootContext.Version == LanguageVersion.ISO_1 && id_builder [0] == '_' && id_builder [1] == '_') {
+                               Report.Error (1638, Location, 
+                                       "`{0}': Any identifier with double underscores cannot be used when ISO language version mode is specified", val);
+                       }
 
                        char [] chars = new char [pos];
                        Array.Copy (id_builder, chars, pos);
 
                        identifiers [pos] [chars] = val;
 
+                       val = new LocatedToken (Location, (string) val);
+                       if (quoted)
+                               escapedIdentifiers.Add (val);
                        return Token.IDENTIFIER;
                }
 
@@ -2047,12 +2115,11 @@ namespace Mono.CSharp
                        
                        val = null;
                        // optimization: eliminate col and implement #directive semantic correctly.
-                       for (;(c = getChar ()) != -1; col++) {
+                       for (;(c = getChar ()) != -1;) {
                                if (c == ' ')
                                        continue;
                                
                                if (c == '\t') {
-                                       col = (((col + 8) / 8) * 8) - 1;
                                        continue;
                                }
                                
@@ -2063,9 +2130,6 @@ namespace Mono.CSharp
                                        if (peekChar () == '\n')
                                                getChar ();
 
-                                       line++;
-                                       ref_line++;
-                                       col = 0;
                                        any_token_seen |= tokens_seen;
                                        tokens_seen = false;
                                        comments_seen = false;
@@ -2082,6 +2146,7 @@ namespace Mono.CSharp
                                                        getChar ();
                                                        // Don't allow ////.
                                                        if ((d = peekChar ()) != '/') {
+                                                               update_comment_location ();
                                                                if (doc_state == XmlCommentState.Allowed)
                                                                        handle_one_line_xml_comment ();
                                                                else if (doc_state == XmlCommentState.NotAllowed)
@@ -2089,11 +2154,7 @@ namespace Mono.CSharp
                                                        }
                                                }
                                                while ((d = getChar ()) != -1 && (d != '\n') && d != '\r')
-                                                       col++;
                                                if (d == '\n'){
-                                                       line++;
-                                                       ref_line++;
-                                                       col = 0;
                                                }
                                                any_token_seen |= tokens_seen;
                                                tokens_seen = false;
@@ -2104,6 +2165,7 @@ namespace Mono.CSharp
                                                bool docAppend = false;
                                                if (RootContext.Documentation != null && peekChar () == '*') {
                                                        getChar ();
+                                                       update_comment_location ();
                                                        // But when it is /**/, just do nothing.
                                                        if (peekChar () == '/') {
                                                                getChar ();
@@ -2121,10 +2183,11 @@ namespace Mono.CSharp
                                                        xml_comment_buffer.Append (Environment.NewLine);
                                                }
 
+                                               Location start_location = Location;
+
                                                while ((d = getChar ()) != -1){
                                                        if (d == '*' && peekChar () == '/'){
                                                                getChar ();
-                                                               col++;
                                                                comments_seen = true;
                                                                break;
                                                        }
@@ -2132,9 +2195,6 @@ namespace Mono.CSharp
                                                                xml_comment_buffer.Append ((char) d);
                                                        
                                                        if (d == '\n'){
-                                                               line++;
-                                                               ref_line++;
-                                                               col = 0;
                                                                any_token_seen |= tokens_seen;
                                                                tokens_seen = false;
                                                                // 
@@ -2144,6 +2204,9 @@ namespace Mono.CSharp
                                                                comments_seen = false;
                                                        }
                                                }
+                                               if (!comments_seen)
+                                                       Report.Error (1035, start_location, "End-of-file found, '*/' expected");
+
                                                if (docAppend)
                                                        update_formatted_doc_comment (current_comment_start);
                                                continue;
@@ -2154,9 +2217,6 @@ namespace Mono.CSharp
                        is_punct_label:
                                // white space
                                if (c == '\n'){
-                                       line++;
-                                       ref_line++;
-                                       col = 0;
                                        any_token_seen |= tokens_seen;
                                        tokens_seen = false;
                                        comments_seen = false;
@@ -2183,17 +2243,12 @@ namespace Mono.CSharp
                                        cont = handle_preprocessing_directive (cont);
 
                                        if (cont){
-                                               col = 0;
                                                continue;
                                        }
-                                       col = 1;
 
                                        bool skipping = false;
-                                       for (;(c = getChar ()) != -1; col++){
+                                       for (;(c = getChar ()) != -1;){
                                                if (c == '\n'){
-                                                       col = 0;
-                                                       line++;
-                                                       ref_line++;
                                                        skipping = false;
                                                } else if (c == ' ' || c == '\t' || c == '\v' || c == '\r' || c == 0xa0)
                                                        continue;
@@ -2205,7 +2260,7 @@ namespace Mono.CSharp
                                        any_token_seen |= tokens_seen;
                                        tokens_seen = false;
                                        if (c == -1)
-                                               Report.Error (1027, Location, "#endif/#endregion expected");
+                                               Report.Error (1027, Location, "Expected `#endif' directive");
                                        continue;
                                }
 
@@ -2233,7 +2288,7 @@ namespace Mono.CSharp
                                        return consume_identifier (c);
                        }
 
-               is_punct_label:
+                       current_location = new Location (ref_line, Col);
                        if ((t = is_punct ((char)c, ref doread)) != Token.ERROR){
                                tokens_seen = true;
                                if (doread){
@@ -2267,6 +2322,10 @@ namespace Mono.CSharp
                                        Report.Error (1011, Location, error_details);
                                        return Token.ERROR;
                                }
+                               if (c == '\r' || c == '\n') {
+                                       Report.Error (1010, Location, "Newline in constant");
+                                       return Token.ERROR;
+                               }
                                c = escape (c);
                                if (c == -1)
                                        return Token.ERROR;
@@ -2280,13 +2339,11 @@ namespace Mono.CSharp
 
                                        // Try to recover, read until newline or next "'"
                                        while ((c = getChar ()) != -1){
-                                               if (c == '\n' || c == '\''){
-                                                       line++;
-                                                       ref_line++;
-                                                       col = 0;
+                                               if (c == '\n'){
+                                                       break;
+                                               }
+                                               else if (c == '\'')
                                                        break;
-                                               } else
-                                                       col++;
                                        }
                                        return Token.ERROR;
                                }
@@ -2328,7 +2385,6 @@ namespace Mono.CSharp
                        while ((c = peekChar ()) == ' ')
                                getChar (); // skip heading whitespaces.
                        while ((c = peekChar ()) != -1 && c != '\n' && c != '\r') {
-                               col++;
                                xml_comment_buffer.Append ((char) getChar ());
                        }
                        if (c == '\r' || c == '\n')
@@ -2366,6 +2422,18 @@ namespace Mono.CSharp
                        xml_comment_buffer.Insert (current_comment_start, String.Join (Environment.NewLine, lines));
                }
 
+               //
+               // Updates current comment location.
+               //
+               private void update_comment_location ()
+               {
+                       if (current_comment_location.IsNull) {
+                               // "-2" is for heading "//" or "/*"
+                               current_comment_location =
+                                       new Location (ref_line, col - 2);
+                       }
+               }
+
                //
                // Checks if there was incorrect doc comments and raise
                // warnings.
@@ -2382,10 +2450,13 @@ namespace Mono.CSharp
                //
                private void warn_incorrect_doc_comment ()
                {
-                       doc_state = XmlCommentState.Error;
-                       // in csc, it is 'XML comment is not placed on a valid 
-                       // language element'. But that does not make sense.
-                       Report.Warning (1587, 2, Location, "XML comment is placed on an invalid language element which can not accept it.");
+                       if (doc_state != XmlCommentState.Error) {
+                               doc_state = XmlCommentState.Error;
+                               // in csc, it is 'XML comment is not placed on 
+                               // a valid language element'. But that does not
+                               // make sense.
+                               Report.Warning (1587, 2, Location, "XML comment is not placed on a valid language element");
+                       }
                }
 
                //
@@ -2396,12 +2467,18 @@ namespace Mono.CSharp
                {
                        if (xml_comment_buffer.Length > 0) {
                                string ret = xml_comment_buffer.ToString ();
-                               xml_comment_buffer.Length = 0;
+                               reset_doc_comment ();
                                return ret;
                        }
                        return null;
                }
 
+               void reset_doc_comment ()
+               {
+                       xml_comment_buffer.Length = 0;
+                       current_comment_location = Location.Null;
+               }
+
                public void cleanup ()
                {
                        if (ifstack != null && ifstack.Count >= 1) {