Infinite loop in the parser fixed

idea/src/org/jetbrains/jet/lang/parsing/JetExpressionParsing.java

@@ -255,7 +255,7 @@ public class JetExpressionParsing extends AbstractJetParsing {
      */
     public void parseExpression() {
         if (!atSet(EXPRESSION_FIRST)) {
-            error("Expecting an element");
+            error("Expecting an expression");
             return;
         }
         parseBinaryExpression(Precedence.ASSIGNMENT);
@@ -952,17 +952,17 @@ public class JetExpressionParsing extends AbstractJetParsing {
      * modifiers declarationRest
      */
     private boolean parseLocalDeclaration() {
-        PsiBuilder.Marker decls = mark();
+        PsiBuilder.Marker decl = mark();
         JetParsing.TokenDetector enumDetector = new JetParsing.TokenDetector(ENUM_KEYWORD);
         myJetParsing.parseModifierList(MODIFIER_LIST, enumDetector);
 
         JetNodeType declType = parseLocalDeclarationRest(enumDetector.isDetected());
 
         if (declType != null) {
-            decls.done(declType);
+            decl.done(declType);
             return true;
         } else {
-            decls.rollbackTo();
+            decl.rollbackTo();
             return false;
         }
     }
@@ -1129,7 +1129,12 @@ public class JetExpressionParsing extends AbstractJetParsing {
      */
     private void parseStatement() {
         if (!parseLocalDeclaration()) {
-            parseExpression();
+            if (!atSet(EXPRESSION_FIRST)) {
+                errorAndAdvance("Expecting a statement");
+            }
+            else {
+                parseExpression();
+            }
         }
     }
 

idea/testData/psi/HangOnLonelyModifier.jet

@@ -0,0 +1,3 @@
+fun test() {
+in
+}

idea/testData/psi/HangOnLonelyModifier.txt

@@ -0,0 +1,17 @@
+JetFile: HangOnLonelyModifier.jet
+  NAMESPACE
+    FUN
+      PsiElement(fun)('fun')
+      PsiWhiteSpace(' ')
+      PsiElement(IDENTIFIER)('test')
+      VALUE_PARAMETER_LIST
+        PsiElement(LPAR)('(')
+        PsiElement(RPAR)(')')
+      PsiWhiteSpace(' ')
+      BLOCK
+        PsiElement(LBRACE)('{')
+        PsiWhiteSpace('\n')
+        PsiErrorElement:Expecting a statement
+          PsiElement(in)('in')
+        PsiWhiteSpace('\n')
+        PsiElement(RBRACE)('}')

idea/testData/psi/When_ERR.txt

@@ -155,7 +155,7 @@ JetFile: When_ERR.jet
                 <empty list>
             PsiWhiteSpace('  ')
             PsiElement(DOUBLE_ARROW)('=>')
-            PsiErrorElement:Expecting an element
+            PsiErrorElement:Expecting an expression
               <empty list>
           PsiWhiteSpace(' ')
           PsiElement(SEMICOLON)(';')