[clang] [clang-format] Keep the space between `not` and a unary operator (PR #135035)

[Owen Pan via cfe-commits]

https://github.com/owenca created https://github.com/llvm/llvm-project/pull/135035

Based on the documentation, it can be argued that SpaceAfterLogicalNot doesn't cover the alternative operator `not`.

Closes #125465

>From c8dab20224467ab0fea8fccf9d55da7417ae0089 Mon Sep 17 00:00:00 2001
From: Owen Pan <owenpiano at gmail.com>
Date: Wed, 9 Apr 2025 07:50:32 -0700
Subject: [PATCH] [clang-format] Keep the space between `not` and a unary
 operator

Based on the documentation, it can be argued that SpaceAfterLogicalNot
doesn't cover the alternative operator `not`.

Closes #125465
---
 clang/lib/Format/TokenAnnotator.cpp   | 7 ++++++-
 clang/unittests/Format/FormatTest.cpp | 5 +++--
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/clang/lib/Format/TokenAnnotator.cpp b/clang/lib/Format/TokenAnnotator.cpp
index bd54470dcba37..31f8a71256fe8 100644
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -5472,7 +5472,12 @@ bool TokenAnnotator::spaceRequiredBefore(const AnnotatedLine &Line,
     // handled.
     if (Left.is(tok::amp) && Right.is(tok::r_square))
       return Style.SpacesInSquareBrackets;
-    return Style.SpaceAfterLogicalNot && Left.is(tok::exclaim);
+    if (Left.isNot(tok::exclaim))
+      return false;
+    if (Left.TokenText == "!")
+      return Style.SpaceAfterLogicalNot;
+    assert(Left.TokenText == "not");
+    return Right.isOneOf(tok::coloncolon, TT_UnaryOperator);
   }
 
   // If the next token is a binary operator or a selector name, we have
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index 69c9ee1d1dcb2..f0e67c604cc4b 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -25393,8 +25393,10 @@ TEST_F(FormatTest, AlternativeOperators) {
   verifyFormat("%:define ABC abc"); // #define ABC abc
   verifyFormat("%:%:");             // ##
 
+  verifyFormat("return not ::f();");
+  verifyFormat("return not *foo;");
+
   verifyFormat("a = v(not;);\n"
-               "b = v(not+);\n"
                "c = v(not x);\n"
                "d = v(not 1);\n"
                "e = v(not 123.f);");
@@ -25402,7 +25404,6 @@ TEST_F(FormatTest, AlternativeOperators) {
   verifyNoChange("#define ASSEMBLER_INSTRUCTION_LIST(V)  \\\n"
                  "  V(and)                               \\\n"
                  "  V(not)                               \\\n"
-                 "  V(not!)                              \\\n"
                  "  V(other)",
                  getLLVMStyleWithColumns(40));
 }