[clang-format] Handle templated elaborated type specifier in function…

[XDeme1]

… return type.

The behavior now is consistent with the non template version.
Enabled and updated old test.

[llvmbot]

@llvm/pr-subscribers-clang-format

Author: None (XDeme)

Changes

… return type.

The behavior now is consistent with the non template version.
Enabled and updated old test.

---

Full diff: https://github.com/llvm/llvm-project/pull/77013.diff

2 Files Affected:

• (modified) clang/lib/Format/UnwrappedLineParser.cpp (+8)
• (modified) clang/unittests/Format/FormatTest.cpp (+1-3)

diff --git a/clang/lib/Format/UnwrappedLineParser.cpp b/clang/lib/Format/UnwrappedLineParser.cpp
index 684609747a5513..aaff6319dd45ef 100644
--- a/clang/lib/Format/UnwrappedLineParser.cpp
+++ b/clang/lib/Format/UnwrappedLineParser.cpp
@@ -3914,7 +3914,15 @@ void UnwrappedLineParser::parseRecord(bool ParseAsExpr) {
   // (this would still leave us with an ambiguity between template function
   // and class declarations).
   if (FormatTok->isOneOf(tok::colon, tok::less)) {
+    int AngleNestingLevel = 0;
     do {
+      if (FormatTok->is(tok::less))
+        ++AngleNestingLevel;
+      else if (FormatTok->is(tok::greater))
+        --AngleNestingLevel;
+
+      if (AngleNestingLevel == 0 && FormatTok->is(tok::r_paren))
+        break;
       if (FormatTok->is(tok::l_brace)) {
         calculateBraceTypes(/*ExpectClassBody=*/true);
         if (!tryToParseBracedList())
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index 762fc8254bdfc9..f304407d0ce2f4 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -14583,9 +14583,7 @@ TEST_F(FormatTest, UnderstandContextOfRecordTypeKeywords) {
   verifyFormat("template <> struct X < 15, i<3 && 42 < 50 && 33 < 28> {};");
   verifyFormat("int i = SomeFunction(a<b, a> b);");
 
-  // FIXME:
-  // This now gets parsed incorrectly as class definition.
-  // verifyFormat("class A<int> f() {\n}\nint n;");
+  verifyFormat("class A<int> f() {}\nint n;");
 
   // Elaborate types where incorrectly parsing the structural element would
   // break the indent.

[HazardyKnusperkeks]

Ok, one last thing. From what I figured it was wrongly detected as class definition. So you could add a token annotator test, which verifies that the { is not an ClassLBrace?

[XDeme1]

Edit: I have updated it to check for a Identifier that is not a macro before a tok::l_paren, this will fix the issue I mentioned below, if this is not recommended I could just revert this change and leave a updated comment about this case.

I have updated the comment a little, because there is some case we can't handle:

template<typename T>
struct Goo<T> F() {}

we can't distinguish if this is a class or function. We could check if F() is macro by checking
if it is all uppercase, to identify a macro, but I am not sure if this is good.

If this is OK, I could do these checks, and possibly remove the entire comment.