Make the parser close parens for you on EOF

[fowles]

Summary

Makes the parser for clang-query auto close all open parens on EOF

[alexfh]

Sam knows this stuff much better.

[sbenza]

Do we want this change in the parser itself? or in clang-query?
clang-query could be helpful enough to add parens when it detect an ET_ParserNoCloseParen error, without changing the language here.

[fowles]

Switching to https://reviews.llvm.org/D33679 for sbenza's suggestion

lib/ASTMatchers/Dynamic/Parser.cpp

while (Tokenizer->nextTokenKind() != TokenInfo::TK_Eof) {
       }
 
       Args.push_back(ArgValue);
       SCE.nextArg();
     }
   }
 
   if (EndToken.Kind == TokenInfo::TK_Eof) {
-    Error->addError(OpenToken.Range, Error->ET_ParserNoCloseParen);
-    return false;
+    // Just assume they want to finish the expression immediately and did not
+    // have enough trailing right parens.
   }
 
   std::string BindID;
   if (Tokenizer->peekNextToken().Kind == TokenInfo::TK_Period) {
     // Parse .bind("foo")
     Tokenizer->consumeNextToken();  // consume the period.
     const TokenInfo BindToken = Tokenizer->consumeNextToken();
     if (BindToken.Kind == TokenInfo::TK_CodeCompletion) {

unittests/ASTMatchers/Dynamic/ParserTest.cpp

EXPECT_EQ(
       "1:9: Error parsing matcher. Found token <123> while looking for ','.",
       ParseWithError("Foo(\"A\" 123)"));
   EXPECT_EQ(
       "1:1: Error parsing argument 1 for matcher stmt.\n"
       "1:6: Value not found: someValue",
       ParseWithError("stmt(someValue)"));
   EXPECT_EQ(
       "1:1: Matcher not found: Foo\n"
-      "1:4: Error parsing matcher. Found end-of-code while looking for ')'.",
       ParseWithError("Foo("));
   EXPECT_EQ("1:1: End of code found while looking for token.",
             ParseWithError(""));
   EXPECT_EQ("Input value is not a matcher expression.",
             ParseMatcherWithError("\"A\""));
   EXPECT_EQ("1:1: Matcher not found: Foo\n"
             "1:1: Error parsing argument 1 for matcher Foo.\n"
             "1:5: Invalid token <(> found when looking for a value.",