[clang-format] [PR43531] clang-format damages "alternative representations" for operators

Summary:
https://bugs.llvm.org/show_bug.cgi?id=43531

Fix for clang-format incorrectly handles "alternative operators" as described by https://en.cppreference.com/w/cpp/language/operator_alternative

compl = ~
not = !

these are unary operators, and clang-format will remove the space between them and a numeric constant

this incorrectly formats the following code

```
int a compl 5;
int a not 5;
```

into:

```
int a compl5;
int a not5;
```

The code adds FIXME unit tests for "alternative token" representations for {} [] and # as defined by the same link, which would require a more detailed change to the FormatTokenLexer

Reviewers: klimek, reuk, owenpan, mitchell-stellar, STL_MSFT

Reviewed By: mitchell-stellar

Subscribers: cfe-commits

Tags: #clang-format, #clang-tools-extra, #clang

Differential Revision: https://reviews.llvm.org/D68332

llvm-svn: 373750

1 files changed, 11 insertions, 1 deletions

diff --git a/clang/lib/Format/TokenAnnotator.cpp b/clang/lib/Format/TokenAnnotator.cpp
index 50e3d056b83..0c417238213 100644
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -2900,9 +2900,19 @@ bool TokenAnnotator::spaceRequiredBefore(const AnnotatedLine &Line,
       return false;
     return true;
   }
-  if (Left.is(TT_UnaryOperator))
+  if (Left.is(TT_UnaryOperator)) {
+    // The alternative operators for ~ and ! are "compl" and "not".
+    // If they are used instead, we do not want to combine them with
+    // the token to the right, unless that is a left paren.
+    if (!Right.is(tok::l_paren)) {
+      if (Left.is(tok::exclaim) && Left.TokenText == "not")
+        return true;
+      if (Left.is(tok::tilde) && Left.TokenText == "compl")
+        return true;
+    }
     return (Style.SpaceAfterLogicalNot && Left.is(tok::exclaim)) ||
            Right.is(TT_BinaryOperator);
+  }
 
   // If the next token is a binary operator or a selector name, we have
   // incorrectly classified the parenthesis as a cast. FIXME: Detect correctly.