[ASTMatcher] Fix a ASTMatcher test failure on Windows.

[aaron.ballman]

Hrm, I kind of worry about this masking bugs when delayed template parsing is enabled (which it is by default on MSVC-built versions of clang).

[thakis]

I agree with Aaron. Maybe you could change Matcher.UnresolvedLookupExpr to call bar() from a new function foo() so that it gets instantiated?

[hokein]

Only use -fno-delayed-template-parsing in the testcase.

[aaron.ballman]

I like this approach much better, thank you. LGTM!

[hokein]

In D20369#433141, @thakis wrote:

Maybe you could change Matcher.UnresolvedLookupExpr to call bar() from a new function foo() so that it gets instantiated?

This will break the intention of the testcase. We don't want the function get instantiated here. Update the code now only restrict -fno-delayed-template-parsing in this test.

[thakis]

unittests/ASTMatchers/ASTMatchersNodeTest.cpp

187

Doesn't referencing bar() after it's defined help too? If not, this is cool too -- maybe add a /*ExpectMatch=*/ in front of true so it's clear what the true means.

[thakis]

Ah, you answered my question while I was writing it.

Doesn't that mean whatever feature this test is testing is broken on Windows?

[thakis]

(If so, maybe add a FIXME comment to make things work without delayed template parsing. In any case, getting the bot green is the most important thing, so landing this as is is definitely fine.)

[alexfh]

unittests/ASTMatchers/ASTMatchersNodeTest.cpp

187

Yes, please add an argument comment and a FIXME to the code that is known to be broken with delayed template parsing. Thanks!

[hokein]

unittests/ASTMatchers/ASTMatchersNodeTest.cpp

187

Done in http://reviews.llvm.org/rL269957.

unittests/ASTMatchers/ASTMatchersNodeTest.cpp

 TEST(EnumConstant, Matches) {
   DeclarationMatcher Matcher = enumConstantDecl(hasName("A"));
   EXPECT_TRUE(matches("enum X{ A };", Matcher));
   EXPECT_TRUE(notMatches("enum X{ B };", Matcher));
   EXPECT_TRUE(notMatches("enum X {};", Matcher));
 }
 
 TEST(Matcher, UnresolvedLookupExpr) {
-  EXPECT_TRUE(matches("template<typename T>"
+  EXPECT_TRUE(matchesConditionally("template<typename T>"
                                    "T foo() { T a; return a; }"
                                    "template<typename T>"
                                    "void bar() {"
                                    "  foo<T>();"
                                    "}",
-                      unresolvedLookupExpr()));
+                                   unresolvedLookupExpr(), true,
+                                   "-fno-delayed-template-parsing"));
 }
 
 TEST(Matcher, Call) {
   // FIXME: Do we want to overload Call() to directly take
   // Matcher<Decl>, too?
   StatementMatcher MethodX =
     callExpr(hasDeclaration(cxxMethodDecl(hasName("x"))));