Made Block.source_reference non-null

Added last_line and last_column to Block.source_reference
Added source_reference to automatically created lambda methods and property accessors
Added a parent_symbol != null check to TypeSymbol so that SeanticAnalyzer won't segfault on incremental parsing

diff --git a/vala/valablock.vala b/vala/valablock.vala
--- a/vala/valablock.vala
+++ b/vala/valablock.vala
@@ -41,7 +41,7 @@ public class Vala.Block : Symbol, Statem
 	 *
 	 * @param source reference to source code
 	 */
-	public Block (SourceReference? source_reference = null) {
+	public Block (SourceReference source_reference) {
 		this.source_reference = source_reference;
 	}
 	
diff --git a/vala/valagenieparser.vala b/vala/valagenieparser.vala
--- a/vala/valagenieparser.vala
+++ b/vala/valagenieparser.vala
@@ -1651,7 +1651,7 @@ public class Vala.Genie.Parser : CodeVis
 
 		comment = scanner.pop_comment ();
 
-		var block = new Block ();
+		var block = new Block (get_src_com (get_location ()));
 		var stmt = parse_embedded_statement_without_block ();
 		if (stmt == null) {
 			// workaround for current limitation of exception handling
diff --git a/vala/valaparser.vala b/vala/valaparser.vala
--- a/vala/valaparser.vala
+++ b/vala/valaparser.vala
@@ -1300,7 +1300,7 @@ public class Vala.Parser : CodeVisitor {
 
 		comment = scanner.pop_comment ();
 
-		var block = new Block ();
+		var block = new Block (get_src_com (get_location ()));
 		var stmt = parse_embedded_statement_without_block ();
 		if (stmt == null) {
 			// workaround for current limitation of exception handling
@@ -1343,6 +1343,9 @@ public class Vala.Parser : CodeVisitor {
 				Report.error (get_current_src (), "expected `}'");
 			}
 		}
+
+		block.source_reference.last_line = get_current_src ().last_line;
+		block.source_reference.last_column = get_current_src ().last_column;
 
 		return block;
 	}
diff --git a/vala/valasemanticanalyzer.vala b/vala/valasemanticanalyzer.vala
--- a/vala/valasemanticanalyzer.vala
+++ b/vala/valasemanticanalyzer.vala
@@ -710,7 +710,7 @@ public class Vala.SemanticAnalyzer : Cod
 					return;
 				}
 				acc.automatic_body = true;
-				acc.body = new Block ();
+				acc.body = new Block (acc.source_reference);
 				var ma = new MemberAccess.simple ("_%s".printf (acc.prop.name), acc.source_reference);
 				if (acc.readable) {
 					acc.body.add_statement (new ReturnStatement (ma, acc.source_reference));
@@ -3375,7 +3375,7 @@ public class Vala.SemanticAnalyzer : Cod
 		}
 
 		if (l.expression_body != null) {
-			var block = new Block ();
+			var block = new Block (l.source_reference);
 			block.scope.parent_scope = l.method.scope;
 
 			if (l.method.return_type.data_type != null) {
diff --git a/vala/valatypesymbol.vala b/vala/valatypesymbol.vala
--- a/vala/valatypesymbol.vala
+++ b/vala/valatypesymbol.vala
@@ -192,7 +192,7 @@ public abstract class Vala.TypeSymbol : 
 	}
 
 	public override Gee.List<string> get_cheader_filenames () {
-		if (cheader_filenames.size == 0) {
+		if (cheader_filenames.size == 0 && parent_symbol != null) {
 			/* default to header filenames of the namespace */
 			foreach (string filename in parent_symbol.get_cheader_filenames ()) {
 				add_cheader_filename (filename);