From 8dd2ef2130852e406dab6097b1feb248bf16ce91 Mon Sep 17 00:00:00 2001
From: Krasimir Georgiev <krasimir@google.com>
Date: Fri, 15 Jul 2022 11:36:08 +0200
Subject: [PATCH] [clang-format] distinguish multiplication after brace-init
 from pointer

After https://github.com/llvm/llvm-project/commit/b646f0955574c6ad4c156c9db522e46f597cfda9,
the added regression test started being formatted as-if the
multiplication `*` was a pointer. This adapts the heuristic to
distinguish between these two cases.

Reviewed By: jackhong12, curdeius, HazardyKnusperkeks, owenpan

Differential Revision: https://reviews.llvm.org/D129771
---
 clang/lib/Format/TokenAnnotator.cpp           | 10 +++++++++-
 clang/unittests/Format/FormatTest.cpp         |  3 +++
 clang/unittests/Format/TokenAnnotatorTest.cpp |  3 +++
 3 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/clang/lib/Format/TokenAnnotator.cpp b/clang/lib/Format/TokenAnnotator.cpp
index 98c012994f45..e0dc7a7f05c9 100644
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -2317,7 +2317,15 @@ private:
     // After right braces, star tokens are likely to be pointers to struct,
     // union, or class.
     //   struct {} *ptr;
-    if (PrevToken->is(tok::r_brace) && Tok.is(tok::star))
+    // This by itself is not sufficient to distinguish from multiplication
+    // following a brace-initialized expression, as in:
+    // int i = int{42} * 2;
+    // In the struct case, the part of the struct declaration until the `{` and
+    // the `}` are put on separate unwrapped lines; in the brace-initialized
+    // case, the matching `{` is on the same unwrapped line, so check for the
+    // presence of the matching brace to distinguish between those.
+    if (PrevToken->is(tok::r_brace) && Tok.is(tok::star) &&
+        !PrevToken->MatchingParen)
       return TT_PointerOrReference;
 
     // For "} &&"
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index ba07584d661a..08cfdbe2cc7a 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -10458,6 +10458,9 @@ TEST_F(FormatTest, UnderstandsUsesOfStarAndAmp) {
   verifyFormat("class {\n"
                "}* ptr;",
                Style);
+  // Don't confuse a multiplication after a brace-initialized expression with
+  // a class pointer.
+  verifyFormat("int i = int{42} * 34;", Style);
   verifyFormat("struct {\n"
                "}&& ptr = {};",
                Style);
diff --git a/clang/unittests/Format/TokenAnnotatorTest.cpp b/clang/unittests/Format/TokenAnnotatorTest.cpp
index df1b05226747..a2474d5c10f8 100644
--- a/clang/unittests/Format/TokenAnnotatorTest.cpp
+++ b/clang/unittests/Format/TokenAnnotatorTest.cpp
@@ -111,6 +111,9 @@ TEST_F(TokenAnnotatorTest, UnderstandsUsesOfStarAndAmp) {
                     "} &&ptr = {};");
   EXPECT_EQ(Tokens.size(), 10u) << Tokens;
   EXPECT_TOKEN(Tokens[3], tok::ampamp, TT_PointerOrReference);
+  Tokens = annotate("int i = int{42} * 2;");
+  EXPECT_EQ(Tokens.size(), 11u) << Tokens;
+  EXPECT_TOKEN(Tokens[7], tok::star, TT_BinaryOperator);
 }
 
 TEST_F(TokenAnnotatorTest, UnderstandsUsesOfPlusAndMinus) {