[clang] [clang-format] Treat `f<N | M>(a)` as template function call (PR #124438)

[Owen Pan via cfe-commits]

https://github.com/owenca updated https://github.com/llvm/llvm-project/pull/124438

>From 8679752fc806d232732bab5da1f53b78c6f7f0e9 Mon Sep 17 00:00:00 2001
From: Owen Pan <owenpiano at gmail.com>
Date: Sat, 25 Jan 2025 15:53:36 -0800
Subject: [PATCH] [clang-format] Treat `f<N | M>(a)` as template function call

Fixes #123144.
---
 clang/lib/Format/TokenAnnotator.cpp           | 8 ++++----
 clang/unittests/Format/TokenAnnotatorTest.cpp | 7 ++++++-
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/clang/lib/Format/TokenAnnotator.cpp b/clang/lib/Format/TokenAnnotator.cpp
index bc41d43d1438c5..2e0145f43ac9a2 100644
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -252,10 +252,10 @@ class AnnotatingParser {
       // parameters.
       // FIXME: This is getting out of hand, write a decent parser.
       if (MaybeAngles && InExpr && !Line.startsWith(tok::kw_template) &&
-          Prev.is(TT_BinaryOperator)) {
-        const auto Precedence = Prev.getPrecedence();
-        if (Precedence > prec::Conditional && Precedence < prec::Relational)
-          MaybeAngles = false;
+          Prev.is(TT_BinaryOperator) &&
+          (Prev.isOneOf(tok::pipepipe, tok::ampamp) ||
+           Prev.getPrecedence() == prec::Equality)) {
+        MaybeAngles = false;
       }
       if (Prev.isOneOf(tok::question, tok::colon) && !Style.isProto())
         SeenTernaryOperator = true;
diff --git a/clang/unittests/Format/TokenAnnotatorTest.cpp b/clang/unittests/Format/TokenAnnotatorTest.cpp
index 10587449dcea95..0b3e5a1499bc63 100644
--- a/clang/unittests/Format/TokenAnnotatorTest.cpp
+++ b/clang/unittests/Format/TokenAnnotatorTest.cpp
@@ -685,7 +685,7 @@ TEST_F(TokenAnnotatorTest, UnderstandsNonTemplateAngleBrackets) {
   EXPECT_TOKEN(Tokens[4], tok::less, TT_BinaryOperator);
   EXPECT_TOKEN(Tokens[8], tok::greater, TT_BinaryOperator);
 
-  Tokens = annotate("return A < B ^ A > B;");
+  Tokens = annotate("return A < B != A > B;");
   ASSERT_EQ(Tokens.size(), 10u) << Tokens;
   EXPECT_TOKEN(Tokens[2], tok::less, TT_BinaryOperator);
   EXPECT_TOKEN(Tokens[6], tok::greater, TT_BinaryOperator);
@@ -3671,6 +3671,11 @@ TEST_F(TokenAnnotatorTest, TemplateInstantiation) {
   EXPECT_TOKEN(Tokens[2], tok::less, TT_TemplateOpener);
   EXPECT_TOKEN(Tokens[6], tok::greater, TT_TemplateCloser);
 
+  Tokens = annotate("return FixedInt<N | M>(foo);");
+  ASSERT_EQ(Tokens.size(), 12u) << Tokens;
+  EXPECT_TOKEN(Tokens[2], tok::less, TT_TemplateOpener);
+  EXPECT_TOKEN(Tokens[6], tok::greater, TT_TemplateCloser);
+
   Tokens = annotate("return std::conditional_t<T::value == U::value, T, U>{};");
   ASSERT_EQ(Tokens.size(), 21u) << Tokens;
   EXPECT_TOKEN(Tokens[4], tok::less, TT_TemplateOpener);