Better error recovery when errant semicolon found in a class.

src/compiler/parser.ts

@@ -619,14 +619,14 @@ module ts {
         }
 
         // True if positioned at the start of a list element
-        function isListElement(kind: ParsingContext): boolean {
+        function isListElement(kind: ParsingContext, inErrorRecovery: boolean): boolean {
             switch (kind) {
                 case ParsingContext.SourceElements:
                 case ParsingContext.ModuleElements:
-                    return isSourceElement();
+                    return isSourceElement(inErrorRecovery);
                 case ParsingContext.BlockStatements:
                 case ParsingContext.SwitchClauseStatements:
-                    return isStatement();
+                    return isStatement(inErrorRecovery);
                 case ParsingContext.SwitchClauses:
                     return token === SyntaxKind.CaseKeyword || token === SyntaxKind.DefaultKeyword;
                 case ParsingContext.TypeMembers:
@@ -650,6 +650,8 @@ module ts {
                 case ParsingContext.TypeArguments:
                     return isType();
             }
+
+            Debug.fail("Non-exhaustive case in 'isListElement'.");
         }
 
         // True if positioned at a list terminator
@@ -717,10 +719,12 @@ module ts {
         }
 
         // True if positioned at element or terminator of the current list or any enclosing list
-        function isInParsingContext(): boolean {
+        function isInSomeParsingContext(): boolean {
             for (var kind = 0; kind < ParsingContext.Count; kind++) {
                 if (parsingContext & (1 << kind)) {
-                    if (isListElement(kind) || isListTerminator(kind)) return true;
+                    if (isListElement(kind, /* inErrorRecovery */ true) || isListTerminator(kind)) {
+                        return true;
+                    }
                 }
             }
 
@@ -734,12 +738,12 @@ module ts {
             var result = <NodeArray<T>>[];
             result.pos = getNodePos();
             while (!isListTerminator(kind)) {
-                if (isListElement(kind)) {
+                if (isListElement(kind, /* inErrorRecovery */ false)) {
                     result.push(parseElement());
                 }
                 else {
                     error(parsingContextErrors(kind));
-                    if (isInParsingContext()) {
+                    if (isInSomeParsingContext()) {
                         break;
                     }
                     nextToken();
@@ -761,7 +765,7 @@ module ts {
             var errorCountBeforeParsingList = file.syntacticErrors.length;
             var commaStart = -1; // Meaning the previous token was not a comma
             while (true) {
-                if (isListElement(kind)) {
+                if (isListElement(kind, /* inErrorRecovery */ false)) {
                     result.push(parseElement());
                     commaStart = scanner.getTokenPos();
                     if (parseOptional(SyntaxKind.CommaToken)) {
@@ -791,7 +795,7 @@ module ts {
                 }
                 else {
                     error(parsingContextErrors(kind));
-                    if (token !== SyntaxKind.CommaToken && isInParsingContext()) {
+                    if (isInSomeParsingContext()) {
                         break;
                     }
                     nextToken();
@@ -2066,12 +2070,19 @@ module ts {
             return finishNode(node);
         }
 
-        function isStatement(): boolean {
+        function isStatement(inErrorRecovery: boolean): boolean {
             switch (token) {
+                case SyntaxKind.SemicolonToken:
+                    // If we're in error recovery, then we don't want to treat ';' as an empty statement.
+                    // The problem is that ';' can show up in far too many contexts, and if we see one 
+                    // and assume it's a statement, then we may bail out innapropriately from whatever 
+                    // we're parsing.  For example, if we have a semicolon in the middle of a class, then
+                    // we really don't want to assume the class is over and we're on a statement in the
+                    // outer module.  We just want to consume and move on.
+                    return !inErrorRecovery;
                 case SyntaxKind.OpenBraceToken:
                 case SyntaxKind.VarKeyword:
                 case SyntaxKind.FunctionKeyword:
-                case SyntaxKind.SemicolonToken:
                 case SyntaxKind.IfKeyword:
                 case SyntaxKind.DoKeyword:
                 case SyntaxKind.WhileKeyword:
@@ -2103,8 +2114,8 @@ module ts {
             }
         }
 
-        function isStatementOrFunction(): boolean {
-            return token === SyntaxKind.FunctionKeyword || isStatement();
+        function isStatementOrFunction(inErrorRecovery: boolean): boolean {
+            return token === SyntaxKind.FunctionKeyword || isStatement(inErrorRecovery);
         }
 
         function parseStatement(): Statement {
@@ -2813,8 +2824,8 @@ module ts {
             return result;
         }
 
-        function isSourceElement(): boolean {
-            return isDeclaration() || isStatement();
+        function isSourceElement(inErrorRecovery: boolean): boolean {
+            return isDeclaration() || isStatement(inErrorRecovery);
         }
 
         function parseSourceElement() {

tests/baselines/reference/ambientGetters.errors.txt

@@ -1,12 +1,10 @@
-==== tests/cases/compiler/ambientGetters.ts (3 errors) ====
+==== tests/cases/compiler/ambientGetters.ts (2 errors) ====
 
     declare class A {
         get length() : number;
                              ~
 !!! '{' expected.
     }
-    ~
-!!! Declaration or statement expected.
 
     declare class B {
         get length() { return 0; }

tests/baselines/reference/es6ClassTest3.errors.txt

@@ -1,45 +1,19 @@
-==== tests/cases/compiler/es6ClassTest3.ts (15 errors) ====
+==== tests/cases/compiler/es6ClassTest3.ts (2 errors) ====
     module M {	
     	class Visibility {
     	    public foo() { };
     	                    ~
 !!! Unexpected token. A constructor, method, accessor, or property was expected.
     	    private bar() { };
-    	    ~~~~~~~
-!!! Declaration or statement expected.
-    	                  ~
-!!! ';' expected.
-    	            ~~~
-!!! Cannot find name 'bar'.
+    	                     ~
+!!! Unexpected token. A constructor, method, accessor, or property was expected.
             private x: number;
-            ~~~~~~~
-!!! Declaration or statement expected.
-                       ~~~~~~
-!!! Cannot find name 'number'.
     	    public y: number;
-    	    ~~~~~~
-!!! Declaration or statement expected.
-    	              ~~~~~~
-!!! Cannot find name 'number'.
     	    public z: number;
-    	    ~~~~~~
-!!! Declaration or statement expected.
-    	              ~~~~~~
-!!! Cannot find name 'number'.
 
     	    constructor() {
-    	                  ~
-!!! ';' expected.
-    	    ~~~~~~~~~~~
-!!! Cannot find name 'constructor'.
     	        this.x = 1;
-    	        ~~~~
-!!! 'this' cannot be referenced in a module body.
     	        this.y = 2;
-    	        ~~~~
-!!! 'this' cannot be referenced in a module body.
     	    }
     	}
-    }
-    ~
-!!! Declaration or statement expected.
+    }

tests/baselines/reference/exportDeclareClass1.errors.txt

@@ -1,26 +1,16 @@
-==== tests/cases/compiler/exportDeclareClass1.ts (9 errors) ====
+==== tests/cases/compiler/exportDeclareClass1.ts (4 errors) ====
         export declare class eaC {
             static tF() { };
                         ~
 !!! A function implementation cannot be declared in an ambient context.
                            ~
 !!! Unexpected token. A constructor, method, accessor, or property was expected.
             static tsF(param:any) { };
-            ~~~~~~
-!!! Declaration or statement expected.
-                            ~
-!!! ',' expected.
                                   ~
-!!! ';' expected.
-                   ~~~
-!!! Cannot find name 'tsF'.
-                       ~~~~~
-!!! Cannot find name 'param'.
-                             ~~~
-!!! Cannot find name 'any'.
+!!! A function implementation cannot be declared in an ambient context.
+                                     ~
+!!! Unexpected token. A constructor, method, accessor, or property was expected.
         };
-        ~
-!!! Declaration or statement expected.
 
     	export declare class eaC2 {
             static tF();

tests/baselines/reference/parser0_004152.errors.txt

@@ -1,4 +1,4 @@
-==== tests/cases/conformance/parser/ecmascript5/Fuzz/parser0_004152.ts (38 errors) ====
+==== tests/cases/conformance/parser/ecmascript5/Fuzz/parser0_004152.ts (34 errors) ====
     export class Game {
     ~~~~~~~~~~~~~~~~~~~
         private position = new DisplayPosition([), 3, 3, 3, 3, 3, 0, 3, 3, 3, 3, 3, 3, 0], NoMove, 0);
@@ -40,8 +40,7 @@
 !!! ';' expected.
                                                                                                      ~
 !!! Unexpected token. A constructor, method, accessor, or property was expected.
-    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! Cannot compile external modules unless the '--module' flag is provided.
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                                ~~~~~~~~~~~~~~~
 !!! Cannot find name 'DisplayPosition'.
                                                       ~
@@ -69,14 +68,9 @@
                                                                                                    ~
 !!! Duplicate identifier '0'.
         private prevConfig: SeedCoords[][];
-        ~~~~~~~
-!!! Declaration or statement expected.
-                                       ~
-!!! Expression expected.
-                                         ~
-!!! Expression expected.
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                             ~~~~~~~~~~
 !!! Cannot find name 'SeedCoords'.
     }
     ~
-!!! Declaration or statement expected.
+!!! Cannot compile external modules unless the '--module' flag is provided.

tests/baselines/reference/parserEqualsGreaterThanAfterFunction2.errors.txt

@@ -1,10 +1,12 @@
-==== tests/cases/conformance/parser/ecmascript5/ErrorRecovery/parserEqualsGreaterThanAfterFunction2.ts (4 errors) ====
+==== tests/cases/conformance/parser/ecmascript5/ErrorRecovery/parserEqualsGreaterThanAfterFunction2.ts (5 errors) ====
     function (a => b;
              ~
 !!! Identifier expected.
                 ~~
 !!! ',' expected.
                     ~
 !!! ',' expected.
+
+!!! ')' expected.
     ~~~~~~~~~~~~~~~~~
 !!! Function implementation expected.