Add better error recovery logic for cases with line ending with "id." followed by a declaration e.g. "class id"

Author: mhegazy

src/compiler/parser.ts

@@ -2198,10 +2198,38 @@ module ts {
 
         function parseCallAndAccess(expr: Expression, inNewExpression: boolean): Expression {
             while (true) {
+                var dotStart = scanner.getTokenPos();
                 if (parseOptional(SyntaxKind.DotToken)) {
                     var propertyAccess = <PropertyAccess>createNode(SyntaxKind.PropertyAccess, expr.pos);
+                    // Technically a keyword is valid here as all keywords are identifier names.
+                    // However, often we'll encounter this in error situations when the keyword
+                    // is actually starting another valid construct.
+                    //
+                    // So, we check for the following specific case:
+                    //
+                    //      name.
+                    //      keyword identifierNameOrKeyword
+                    //
+                    // Note: the newlines are important here.  For example, if that above code 
+                    // were rewritten into:
+                    //
+                    //      name.keyword
+                    //      identifierNameOrKeyword
+                    //
+                    // Then we would consider it valid.  That's because ASI would take effect and
+                    // the code would be implicitly: "name.keyword; identifierNameOrKeyword".  
+                    // In the first case though, ASI will not take effect because there is not a
+                    // line terminator after the keyword.
+                    if (scanner.hasPrecedingLineBreak() && scanner.isReservedWord() && lookAhead(() => scanner.isReservedWord())) {
+                        grammarErrorAtPos(dotStart, scanner.getStartPos() - dotStart, Diagnostics.Identifier_expected);
+                        var id = <Identifier>createMissingNode();
+                    }
+                    else {
+                        var id = parseIdentifierName();
+                    }
+
                     propertyAccess.left = expr;
-                    propertyAccess.right = parseIdentifierName();
+                    propertyAccess.right = id;
                     expr = finishNode(propertyAccess);
                     continue;
                 }

tests/baselines/reference/enumConflictsWithGlobalIdentifier.errors.txt

@@ -3,9 +3,9 @@
         IgnoreRulesSpecific = 0,
     }
     var x = IgnoreRulesSpecific.
+                               ~
+!!! Identifier expected.
             ~~~~~~~~~~~~~~~~~~~
 !!! Cannot find name 'IgnoreRulesSpecific'.
     var y = Position.IgnoreRulesSpecific;
-        ~
-!!! ',' expected.
 

tests/baselines/reference/enumMemberResolution.errors.txt

@@ -3,10 +3,10 @@
         IgnoreRulesSpecific = 0
     }
     var x = IgnoreRulesSpecific. // error
+                               ~
+!!! Identifier expected.
             ~~~~~~~~~~~~~~~~~~~
 !!! Cannot find name 'IgnoreRulesSpecific'.
     var y = 1;
-        ~
-!!! ',' expected.
     var z = Position2.IgnoreRulesSpecific; // no error
 

tests/cases/fourslash/memberListOfModuleBeforeKeyword.ts

@@ -16,9 +16,9 @@
 
 // Verify the memberlist of module when the following line has a keyword
 goTo.marker('namedType');
-verify.completionListContains('C1', 'TypeModule1.C1');
-verify.completionListContains('C2', 'TypeModule1.C2');
+verify.completionListContains('C1');
+verify.completionListContains('C2');
 
 goTo.marker('dotedExpression');
-verify.completionListContains('C1', 'TypeModule1.C1');
-verify.completionListContains('C2', 'TypeModule1.C2');
+verify.completionListContains('C1');
+verify.completionListContains('C2');