[clang] [clang-format] Recognize Verilog followed-by operators (PR #165594)

[via cfe-commits]

https://github.com/sstwcw created https://github.com/llvm/llvm-project/pull/165594

When formatting Verilog code, the program changes the hash to `kw_verilogHash` and the backtick to `tok::hash`.  The developer did not take that into account when writing the part for recognizing the `#-#` and `#=#` operators.  The part did not work.  The program would add a space within the operator.

after

```SystemVerilog
##[0 : 5] done #-# always !rst;
```

before

```SystemVerilog
##[0 : 5] done #- #always !rst;
```

>From 8d6f6905e1d28ced6a89b63f65f6cb4e0aa07e2e Mon Sep 17 00:00:00 2001
From: sstwcw <su3e8a96kzlver at posteo.net>
Date: Wed, 29 Oct 2025 16:38:24 +0000
Subject: [PATCH] [clang-format] Recognize Verilog followed-by operators

When formatting Verilog code, the program changes the hash to
`kw_verilogHash` and the backtick to `tok::hash`.  The developer did not
take that into account when writing the part for recognizing the `#-#`
and `#=#` operators.  The part did not work.  The program would add a
space within the operator.

after

```SystemVerilog
##[0 : 5] done #-# always !rst;
```

before

```SystemVerilog
##[0 : 5] done #- #always !rst;
```
---
 clang/lib/Format/FormatTokenLexer.cpp         | 13 ++++++++++---
 clang/unittests/Format/TokenAnnotatorTest.cpp |  1 +
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/clang/lib/Format/FormatTokenLexer.cpp b/clang/lib/Format/FormatTokenLexer.cpp
index ab3293841a2a4..a9ea5ec9009c4 100644
--- a/clang/lib/Format/FormatTokenLexer.cpp
+++ b/clang/lib/Format/FormatTokenLexer.cpp
@@ -318,14 +318,21 @@ void FormatTokenLexer::tryMergePreviousTokens() {
                            {tok::equal, tok::greater},
                            {tok::star, tok::greater},
                            {tok::pipeequal, tok::greater},
-                           {tok::pipe, tok::arrow},
-                           {tok::hash, tok::minus, tok::hash},
-                           {tok::hash, tok::equal, tok::hash}},
+                           {tok::pipe, tok::arrow}},
                           TT_BinaryOperator) ||
         Tokens.back()->is(tok::arrow)) {
       Tokens.back()->ForcedPrecedence = prec::Comma;
       return;
     }
+    if (Tokens.size() >= 3 &&
+        Tokens[Tokens.size() - 3]->is(Keywords.kw_verilogHash) &&
+        Tokens[Tokens.size() - 2]->isOneOf(tok::minus, tok::equal) &&
+        Tokens[Tokens.size() - 1]->is(Keywords.kw_verilogHash) &&
+        tryMergeTokens(3, TT_BinaryOperator)) {
+      Tokens.back()->setFinalizedType(TT_BinaryOperator);
+      Tokens.back()->ForcedPrecedence = prec::Comma;
+      return;
+    }
   } else if (Style.isTableGen()) {
     // TableGen's Multi line string starts with [{
     if (tryMergeTokens({tok::l_square, tok::l_brace},
diff --git a/clang/unittests/Format/TokenAnnotatorTest.cpp b/clang/unittests/Format/TokenAnnotatorTest.cpp
index c046142c613b0..6c05feaeb13e0 100644
--- a/clang/unittests/Format/TokenAnnotatorTest.cpp
+++ b/clang/unittests/Format/TokenAnnotatorTest.cpp
@@ -2686,6 +2686,7 @@ TEST_F(TokenAnnotatorTest, UnderstandsVerilogOperators) {
   // precedence.
   std::pair<prec::Level, std::string> JoinedBinary[] = {
       {prec::Comma, "->"},        {prec::Comma, "<->"},
+      {prec::Comma, "#-#"},       {prec::Comma, "#=#"},
       {prec::Assignment, "+="},   {prec::Assignment, "-="},
       {prec::Assignment, "*="},   {prec::Assignment, "/="},
       {prec::Assignment, "%="},   {prec::Assignment, "&="},