Address code review feedback

Author: ahejlsberg

src/compiler/binder.ts

@@ -1285,7 +1285,8 @@ namespace ts {
         }
 
         function isDottedName(node: Expression): boolean {
-            return node.kind === SyntaxKind.Identifier || node.kind === SyntaxKind.PropertyAccessExpression && isDottedName((<PropertyAccessExpression>node).expression);
+            return node.kind === SyntaxKind.Identifier || node.kind === SyntaxKind.ThisKeyword ||
+                node.kind === SyntaxKind.PropertyAccessExpression && isDottedName((<PropertyAccessExpression>node).expression);
         }
 
         function bindExpressionStatement(node: ExpressionStatement): void {

src/compiler/checker.ts

@@ -16838,16 +16838,18 @@ namespace ts {
             // that reference function, method, class or value module symbols; or variable, property or
             // parameter symbols with declarations that have explicit type annotations. Such references are
             // resolvable with no possibility of triggering circularities in control flow analysis.
-            if (node.kind === SyntaxKind.Identifier) {
-                const symbol = getResolvedSymbol(<Identifier>node);
-                return getExplicitTypeOfSymbol(symbol.flags & SymbolFlags.Alias ? resolveAlias(symbol) : symbol);
-            }
-            if (node.kind === SyntaxKind.PropertyAccessExpression) {
-                const type = getTypeOfDottedName((<PropertyAccessExpression>node).expression);
-                if (type) {
-                    const prop = getPropertyOfType(type, (<PropertyAccessExpression>node).name.escapedText);
-                    return prop && getExplicitTypeOfSymbol(prop);
-                }
+            switch (node.kind) {
+                case SyntaxKind.Identifier:
+                    const symbol = getResolvedSymbol(<Identifier>node);
+                    return getExplicitTypeOfSymbol(symbol.flags & SymbolFlags.Alias ? resolveAlias(symbol) : symbol);
+                case SyntaxKind.ThisKeyword:
+                    return checkThisExpression(node);
+                case SyntaxKind.PropertyAccessExpression:
+                    const type = getTypeOfDottedName((<PropertyAccessExpression>node).expression);
+                    if (type) {
+                        const prop = getPropertyOfType(type, (<PropertyAccessExpression>node).name.escapedText);
+                        return prop && getExplicitTypeOfSymbol(prop);
+                    }
             }
         }
 

src/compiler/parser.ts

@@ -3211,6 +3211,7 @@ namespace ts {
             const type = parseType();
             if (typePredicateVariable) {
                 const node = <TypePredicateNode>createNode(SyntaxKind.TypePredicate, typePredicateVariable.pos);
+                node.assertsModifier = undefined;
                 node.parameterName = typePredicateVariable;
                 node.type = type;
                 return finishNode(node);
@@ -3232,9 +3233,7 @@ namespace ts {
             const node = <TypePredicateNode>createNode(SyntaxKind.TypePredicate);
             node.assertsModifier = parseExpectedToken(SyntaxKind.AssertsKeyword);
             node.parameterName = parseIdentifier();
-            if (parseOptional(SyntaxKind.IsKeyword)) {
-                node.type = parseType();
-            }
+            node.type = parseOptional(SyntaxKind.IsKeyword) ? parseType() : undefined;
             return finishNode(node);
         }