Fixed the /**/ case. It is now a comment

compiler/frontend/src/org/jetbrains/jet/lexer/Jet.flex

@@ -164,6 +164,10 @@ LONG_TEMPLATE_ENTRY_END=\}
 
 // (Nested) comments
 
+"/**/" {
+    return JetTokens.BLOCK_COMMENT;
+}
+
 "/**" {
     pushState(DOC_COMMENT);
     commentDepth = 0;

compiler/testData/psi/NestedComments.jet

@@ -10,10 +10,10 @@ b
 b
 /***/
 b
-/**/***/*/
+/** /***/*/
 b
 /** /**
 
 */***/
 b
-}
+}

compiler/testData/psi/NestedComments.txt

@@ -17,11 +17,27 @@ JetFile: NestedComments.jet
       REFERENCE_EXPRESSION
         PsiElement(IDENTIFIER)('b')
       PsiWhiteSpace('\n')
-      PsiComment(DOC_COMMENT)('/**/\nb\n/* */\nb\n/*/**/*/\nb\n/***/\nb\n/**/***/')
+      PsiComment(BLOCK_COMMENT)('/**/')
-      PsiErrorElement:Expecting an element
+      PsiWhiteSpace('\n')
-        PsiElement(MUL)('*')
+      REFERENCE_EXPRESSION
-      PsiErrorElement:Unexpected tokens (use ';' to separate expressions on the same line)
+        PsiElement(IDENTIFIER)('b')
-        PsiElement(DIV)('/')
+      PsiWhiteSpace('\n')
+      PsiComment(BLOCK_COMMENT)('/* */')
+      PsiWhiteSpace('\n')
+      REFERENCE_EXPRESSION
+        PsiElement(IDENTIFIER)('b')
+      PsiWhiteSpace('\n')
+      PsiComment(BLOCK_COMMENT)('/*/**/*/')
+      PsiWhiteSpace('\n')
+      REFERENCE_EXPRESSION
+        PsiElement(IDENTIFIER)('b')
+      PsiWhiteSpace('\n')
+      PsiComment(DOC_COMMENT)('/***/')
+      PsiWhiteSpace('\n')
+      REFERENCE_EXPRESSION
+        PsiElement(IDENTIFIER)('b')
+      PsiWhiteSpace('\n')
+      PsiComment(DOC_COMMENT)('/** /***/*/')
       PsiWhiteSpace('\n')
       REFERENCE_EXPRESSION
         PsiElement(IDENTIFIER)('b')