Make clang-query close parens for you

[fowles]

Summary

Make clang-query close parens for you

[fowles]

Add a test

[fowles]

Add tests for real

clang-query/QueryParser.cpp

 #include "QueryParser.h"
 #include "Query.h"
 #include "QuerySession.h"
 #include "clang/ASTMatchers/Dynamic/Parser.h"
 #include "clang/Basic/CharInfo.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/StringSwitch.h"
 #include <set>
+#include <string>
 
 using namespace llvm;
 using namespace clang::ast_matchers::dynamic;
 
 namespace clang {
 namespace query {
 
 // Lex any amount of whitespace followed by a "word" (any sequence of
case PQK_Let: {
 
     return new LetQuery(Name, Value);
   }
 
   case PQK_Match: {
     if (CompletionPos)
       return completeMatcherExpression();
 
+    Diagnostics FirstDiag;
+    std::string Query = StringRef(Begin, End - Begin).str();
+    while (true) {
       Diagnostics Diag;
+      Diagnostics* CurrentDiag = FirstDiag.errors().empty() ? &FirstDiag : &Diag;
       Optional<DynTypedMatcher> Matcher = Parser::parseMatcherExpression(
-        StringRef(Begin, End - Begin), nullptr, &QS.NamedValues, &Diag);
-    if (!Matcher) {
-      return makeInvalidQueryFromDiagnostics(Diag);
-    }
+          Query, nullptr, &QS.NamedValues, CurrentDiag);
+      if (Matcher) {
         return new MatchQuery(*Matcher);
       }
+      for (const auto& Error : CurrentDiag->errors()) {
+        for (const auto &Message : Error.Messages) {
+          if (Message.Type == Diagnostics::ET_ParserNoCloseParen) {
+            Query += ")";
+          } else {
+            // Report the first error before we mucked with the query.
+            return makeInvalidQueryFromDiagnostics(FirstDiag);
+          }
+        }
+      }
+    }
+  }
 
   case PQK_Set: {
     StringRef VarStr;
     ParsedQueryVariable Var = lexOrCompleteWord<ParsedQueryVariable>(VarStr)
                                   .Case("output", PQV_Output)
                                   .Case("bind-root", PQV_BindRoot)
                                   .Default(PQV_Invalid);
     if (VarStr.empty())

test/clang-query/missing-parens.c

+// RUN: clang-query -c "match functionDecl(" %s -- | FileCheck %s
+
+// CHECK: function-decl.c:4:1: note: "root" binds here
+void foo(void) {}