Revert patch 55055 as it fails to build the following code:

	for (LinkedList<int> a = null; ;)

The problem is that simple-name-deambiguation is turned on at this point
because the flag in_namespace_or_typename is false.


svn path=/trunk/mcs/; revision=55075

3 files changed, 49 insertions, 289 deletions

diff --git a/mcs/gmcs/ChangeLog b/mcs/gmcs/ChangeLog
index c806148f9e2..97faccc8dba 100644
--- a/mcs/gmcs/ChangeLog
+++ b/mcs/gmcs/ChangeLog
@@ -4,62 +4,6 @@
 	doing a low-level comparission of parameter types.  It was lacking
 	a check for __argslist. 
 
-2006-01-04  Miguel de Icaza  <miguel@novell.com>
-
-	* cs-parser.jay (in_namespace_or_typename): This variable is used
-	to pass information down to member-name that we are parsing
-	namespace_or_type_name and that it should not activate the
-	grammar deambiguation.
-
-	(namespace_or_type_name): Inline the member_name production here
-	so we can avoid a shift/reduce conflict as we need to turn off
-	simple-name-deamiguation after the identifier is seen. 
-
-	(primary_expression): Replace member_name and IDENTIFIER
-	DOUBLE_COLON IDENTIFIER rules with a merged rule.  This is
-	required to control the lexer simple-name-deambuguation feature
-	which needs to be activated after the first IDENTIFIER has been
-	parsed.
-
-	The new merged rule is member_name_or_qualified_alias.
-
-	(member_name_or_qualified_alias): This rules is a combination of
-	member_name and IDENTIFIER DOUBLE_COLON IDENTIFIER.   After the
-	first IDENTIFIER is parsed we enable the simple-name-deambuguation
-	flag in the lexer if we are not in a namespace or typename. 
-
-	* cs-tokenizer.cs: Add support for simple-name-deambuguation which
-	is specified in section 9.2.3 of the third edition of the C#
-	specification. 
-
-	simple-name-deambuguation is a short-hand for the actual required
-	cases: simple-name, member-access and pointer-member-access.
-	During those context we must check the token to deambiguate the
-	expression.
-
-	(next_token_is_allowed_after_generic_closing): This routine
-	implements the check for the next-token.
-
-	This routine currently contains a hack: it considers "[" a valid
-	character after the >.  This is against the spec, but we require
-	it for this particular cast:
-
-		(Blah<a,b>[])
-
-	This is probably a sign that something is wrong elsewhere.
-
-	(Position): Introduce a new class to track the current position
-	instead of saving all the state everywhere.  The state was being
-	incorrecly saved/restored in the past (not complete enough
-	everywhere).  
-
-	Maybe this should become a struct, and saving should not use a
-	parallel stack, but just use a construct like:
-
-		Position save = current_position;
-		xxxx
-		current_position = save;
-
 2005-12-30  Miguel de Icaza  <miguel@novell.com>
 
 	* expression.cs (ParameterReference.DoResolveBase): Allow
diff --git a/mcs/gmcs/cs-parser.jay b/mcs/gmcs/cs-parser.jay
index e8c76c34a94..fc62f9fc2c5 100644
--- a/mcs/gmcs/cs-parser.jay
+++ b/mcs/gmcs/cs-parser.jay
@@ -104,13 +104,6 @@ namespace Mono.CSharp
 		bool global_attrs_enabled = true;
 		bool has_get, has_set;
 
-		//
-		// Used to pass information down to member-name that we are 
-		// parsing namespace_or_type_name and that it should not
-		// activate the grammar deambiguation.
-		//
-		bool in_namespace_or_typename;
-
 %}
 
 %token EOF
@@ -2702,39 +2695,18 @@ opt_nullable
 	;
 
 namespace_or_type_name
-	: // 
-	  // inline member_name here
-	  //
-	  // IMPORTANT: Keep in sync with member_name (modulo the PushSND handling)
-	  //
-	  IDENTIFIER { 
-		lexer.PushSND (false);
-		oob_stack.Push (in_namespace_or_typename);
-		in_namespace_or_typename = true;
-	  } opt_type_argument_list {
-		lexer.PopSND ();
-		in_namespace_or_typename = (bool) oob_stack.Pop ();
-		LocatedToken lt = (LocatedToken) $1;
-		$$ = new MemberName (lt.Value, (TypeArguments) $3, lt.Location);
-	  }
+	: member_name
 	| IDENTIFIER DOUBLE_COLON IDENTIFIER {
 		LocatedToken lt1 = (LocatedToken) $1;
 		LocatedToken lt2 = (LocatedToken) $3;
 		$$ = new MemberName (lt1.Value, lt2.Value, lt2.Location);
 	  }
-	| namespace_or_type_name DOT {
-		lexer.PushSND (false);
-	  } IDENTIFIER opt_type_argument_list {
-		lexer.PopSND ();
-		LocatedToken lt = (LocatedToken) $4;
-		$$ = new MemberName ((MemberName) $1, lt.Value, (TypeArguments) $5, lt.Location);
+	| namespace_or_type_name DOT IDENTIFIER opt_type_argument_list {
+		LocatedToken lt = (LocatedToken) $3;
+		$$ = new MemberName ((MemberName) $1, lt.Value, (TypeArguments) $4, lt.Location);
 	  }
 	;
 
-	//
-	// IMPORTANT:
-	// keep this code in sync (modulo handling of PushSND) with namespace_or_type_name
-	//
 member_name
 	: IDENTIFIER opt_type_argument_list {
 		LocatedToken lt = (LocatedToken) $1;
@@ -2750,7 +2722,6 @@ opt_type_argument_list
 		if (RootContext.Version == LanguageVersion.ISO_1)
 			Report.FeatureIsNotStandardized (lexer.Location, "generics");
 	  }
-
 	| GENERIC_DIMENSION
 	  {
 		$$ = new TypeArguments ((int) $1, lexer.Location);
@@ -2786,6 +2757,7 @@ type_arguments
 	  }
 	;
 
+	
 /* 
  * Before you think of adding a return_type, notice that we have been
  * using two rules in the places where it matters (one rule using type
@@ -2920,50 +2892,6 @@ array_type
 	  }
 	;
 
-type_argument_list_or_qualified
-	: opt_type_argument_list
-	| DOUBLE_COLON IDENTIFIER { $$ = $2; }
-	;
-
-//
-// This is used so we can push the SimpleNameDeambiguation state
-// before we parse a member-base (which might need the extra token
-// reading to deamiguate).
-//
-// To avoid a grammar conflict between a qualified-alias and a 
-// member-name, I merged both rules into this one and call
-// PushSND before.  It does not matter/hurt QualifiedAliasMember
-// and helps our cause
-//
-// This production merges two old productions in primary-expression:
-//  | member_name
-//  | IDENTIFIER DOUBLE_COLON IDENTIFIER
-//
-
-member_name_or_qualified_alias 
-	: IDENTIFIER 
-	  { 
-		lexer.PushSND (in_namespace_or_typename == false); 
-	  } 
-	  type_argument_list_or_qualified
-	  {
-		lexer.PopSND ();
-
-		//
-		// Its a member-name with or without type-arguments
-		//
-		if ($3 == null || $3 is TypeArguments){
-			LocatedToken lt = (LocatedToken) $1;
-			MemberName mn = new MemberName (lt.Value, (TypeArguments) $3, lt.Location);
-			$$ = mn.GetTypeExpression ();
-		} else {
-			LocatedToken lt1 = (LocatedToken) $1;
-			LocatedToken lt2 = (LocatedToken) $3;
-			$$ = new QualifiedAliasMember (lt1.Value, lt2.Value, lt2.Location);
-		}
-	  }
-	;
-
 //
 // Expressions, section 7.5
 //
@@ -2972,7 +2900,17 @@ primary_expression
 	  {
 		// 7.5.1: Literals
 	  }
-	| member_name_or_qualified_alias 
+ 	| member_name
+	  {
+		MemberName mn = (MemberName) $1;
+		$$ = mn.GetTypeExpression ();
+	  }
+	| IDENTIFIER DOUBLE_COLON IDENTIFIER
+	  {
+		LocatedToken lt1 = (LocatedToken) $1;
+		LocatedToken lt2 = (LocatedToken) $3;
+		$$ = new QualifiedAliasMember (lt1.Value, lt2.Value, lt2.Location);
+	  }
 	| parenthesized_expression
 	| default_value_expression
 	| member_access
@@ -4103,7 +4041,7 @@ opt_statement_list
 	;
 
 statement_list
-	: statement 
+	: statement
 	| statement_list statement
 	;
 
diff --git a/mcs/gmcs/cs-tokenizer.cs b/mcs/gmcs/cs-tokenizer.cs
index 7a61c61970a..da63a863aa7 100644
--- a/mcs/gmcs/cs-tokenizer.cs
+++ b/mcs/gmcs/cs-tokenizer.cs
@@ -44,7 +44,6 @@ namespace Mono.CSharp
 		bool handle_assembly = false;
 		bool handle_constraints = false;
 		bool handle_typeof = false;
-		bool simple_name_deambiguation = false;
 		Location current_location;
 		Location current_comment_location = Location.Null;
 		ArrayList escapedIdentifiers = new ArrayList ();
@@ -173,25 +172,6 @@ namespace Mono.CSharp
 			}
 		}
 
-		Stack state = new Stack ();
-
-		//
-		// Sets the new state for the simple-name-deambiguation.
-		//
-		public void PushSND (bool value)
-		{
-			state.Push (simple_name_deambiguation);
-			simple_name_deambiguation = value;
-		}
-
-		//
-		// Restores the previous state for the simple-name-deambiguation.
-		//
-		public void PopSND ()
-		{
-			simple_name_deambiguation = (bool) state.Pop ();
-		}
-		
 		public XmlCommentState doc_state {
 			get { return xmlDocState; }
 			set {
@@ -275,55 +255,6 @@ namespace Mono.CSharp
 			}
 		}
 
-		//
-		// This is used when the tokenizer needs to save
-		// the current position as it needs to do some parsing
-		// on its own to deamiguate a token in behalf of the
-		// parser.
-		//
-		Stack position_stack = new Stack ();
-		class Position {
-			public int position;
-			public int ref_line;
-			public int col;
-			public int putback_char;
-			public int previous_col;
-			public int parsing_generic_less_than;
-			
-			public Position (Tokenizer t)
-			{
-				position = t.reader.Position;
-				ref_line = t.ref_line;
-				col = t.col;
-				putback_char = t.putback_char;
-				previous_col = t.previous_col;
-				parsing_generic_less_than = t.parsing_generic_less_than;
-			}
-		}
-		
-		public void PushPosition ()
-		{
-			position_stack.Push (new Position (this));
-		}
-
-		public void PopPosition ()
-		{
-			Position p = (Position) position_stack.Pop ();
-
-			reader.Position = p.position;
-			ref_line = p.ref_line;
-			col = p.col;
-			putback_char = p.putback_char;
-			previous_col = p.previous_col;
-
-		}
-
-		// Do not reset the position, ignore it.
-		public void DiscardPosition ()
-		{
-			position_stack.Pop ();
-		}
-		
 		static void AddKeyword (string kw, int token) {
 			keywordStrings.Add (kw, kw);
 			if (keywords [kw.Length] == null) {
@@ -547,12 +478,7 @@ namespace Mono.CSharp
 			return false;
 		}
 
-		//
-		// The level indicates the nestedness level.  This is required
-		// to perform the extra check in case that simple_name_deambiguation
-		// is set to true
-		//
-		bool parse_less_than (int level)
+		bool parse_less_than ()
 		{
 		start:
 			int the_token = token ();
@@ -588,25 +514,14 @@ namespace Mono.CSharp
 		again:
 			the_token = token ();
 
-			if (the_token == Token.OP_GENERICS_GT){
-				//
-				// Check for the 9.2.3 special cases
-				//
-				if (level == 0 && simple_name_deambiguation){
-					PushPosition ();
-					bool v = next_token_is_allowed_after_generic_closing ();
-					PopPosition ();
-					return v;
-				}
+			if (the_token == Token.OP_GENERICS_GT)
 				return true;
-			}
-			
 			else if ((the_token == Token.COMMA) || (the_token == Token.DOT))
 				goto start;
 			else if (the_token == Token.INTERR)
 				goto again;
 			else if (the_token == Token.OP_GENERICS_LT) {
-				if (!parse_less_than (level+1))
+				if (!parse_less_than ())
 					return false;
 				goto again;
 			} else if (the_token == Token.OPEN_BRACKET) {
@@ -622,61 +537,7 @@ namespace Mono.CSharp
 			return false;
 		}
 
-		//
-		// This method is used to deamiguate the meaning of '>'
-		// while parsing a '<'...'>' structure.  It implements the
-		// check specified in 9.2.3 "Grammar Ambiguities" on the C# 3rd
-		// edition
-		//
-		bool next_token_is_allowed_after_generic_closing ()
-		{
-			PushPosition ();
-			int next_token = token ();
-			bool ret;
-
-			//Console.WriteLine ("NextToken used for deambiguation is: " + next_token);
-			if (next_token == Token.OPEN_PARENS ||
-			    next_token == Token.CLOSE_PARENS ||
-			    next_token == Token.CLOSE_PARENS_OPEN_PARENS ||
-			    next_token == Token.CLOSE_PARENS_MINUS ||
-			    next_token == Token.CLOSE_PARENS_CAST ||
-			    next_token == Token.CLOSE_PARENS_NO_CAST ||
-			    next_token == Token.CLOSE_PARENS ||
-			    next_token == Token.CLOSE_BRACKET ||
-			    next_token == Token.COLON || next_token == Token.SEMICOLON ||
-			    next_token == Token.COMMA || next_token == Token.DOT ||
-			    next_token == Token.INTERR ||
-			    next_token == Token.OP_NE || next_token == Token.OP_EQ)
-				ret = true;
-			else
-				ret = false;
-
-			//
-			// The following line is a *hack*, it is here to parse:
-			// (Blah<a,b>[]) case.   but it is likely going to show
-			// up as another bug elsewhere.
-			//
-			// The following test case fails without this:
-			//
-			// namespace System.Collections.Generic {
-			// public class Dictionary<TKey, TValue> {
-			// public void ContainsValue (object b){ 
-			// object a = (KeyValuePair<TKey, TValue> []) b;
-			// } }
-			//
-			// This probably means that we should have turned
-			// deambuguation off in this particular context, but
-			// am puzzled about how to fix it.
-			//
-			if (next_token == Token.OPEN_BRACKET)
-				ret = true;
-
-			PopPosition ();
-
-			return ret;
-		}
-		
-		public int parsing_generic_less_than = 0;
+		int parsing_generic_less_than = 0;
 
 		int is_punct (char c, ref bool doread)
 		{
@@ -707,9 +568,16 @@ namespace Mono.CSharp
 
 				--deambiguate_close_parens;
 
-				PushPosition ();
+				// 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 ();
-				PopPosition ();
+				reader.Position = old;
+				ref_line = old_ref_line;
+				col = old_col;
+				putback_char = -1;
 
 				if (new_token == Token.OPEN_PARENS)
 					return Token.CLOSE_PARENS_OPEN_PARENS;
@@ -737,21 +605,22 @@ namespace Mono.CSharp
 				if (parsing_generic_less_than++ > 0)
 					return Token.OP_GENERICS_LT;
 
+				int old = reader.Position;
 				if (handle_typeof) {
 					int dimension;
-					PushPosition ();
 					if (parse_generic_dimension (out dimension)) {
 						val = dimension;
-						DiscardPosition ();
 						return Token.GENERIC_DIMENSION;
 					}
-					PopPosition ();
+					reader.Position = old;
+					putback_char = -1;
 				}
 
 				// Save current position and parse next token.
-				PushPosition ();
-				bool is_generic_lt = parse_less_than (0);
-				PopPosition ();
+				old = reader.Position;
+				bool is_generic_lt = parse_less_than ();
+				reader.Position = old;
+				putback_char = -1;
 
 				if (is_generic_lt) {
 					parsing_generic_less_than++;
@@ -1383,7 +1252,8 @@ namespace Mono.CSharp
 			if (putback_char != -1) {
 				x = putback_char;
 				putback_char = -1;
-			} else
+			}
+			else
 				x = reader.Read ();
 			if (x == '\n') {
 				line++;
@@ -2145,7 +2015,12 @@ namespace Mono.CSharp
 
 			if (res == Token.PARTIAL) {
 				// Save current position and parse next token.
-				PushPosition ();
+				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) ||
@@ -2153,7 +2028,10 @@ namespace Mono.CSharp
 					(next_token == Token.INTERFACE) ||
 					(next_token == Token.ENUM); // "partial" is a keyword in 'partial enum', even though it's not valid
 
-				PopPosition ();
+				reader.Position = old;
+				ref_line = old_ref_line;
+				col = old_col;
+				putback_char = old_putback;
 
 				if (ok)
 					return res;