[PATCH] D45927: [clang-tidy] [modernize-use-auto] Correct way to calculate a type name length for multi-token types

[Alexander Kornienko via Phabricator via cfe-commits]

alexfh requested changes to this revision.
alexfh added inline comments.
This revision now requires changes to proceed.


================
Comment at: clang-tidy/modernize-use-auto-min-type-name-length.cpp:61-83
+    long int li = static_cast<long int>(foo<long int>());
+    // CHECK-FIXES-0-0: auto li = {{.*}}
+    // CHECK-FIXES-0-5: auto li = {{.*}}
+    // CHECK-FIXES-1-0: auto  li = {{.*}}
+    // CHECK-FIXES-1-5: auto  li = {{.*}}
+    long int *pli = static_cast<long int *>(foo<long int*>());
+    // CHECK-FIXES-0-0: auto *pli = {{.*}}
----------------
These tests could be more useful, if they verified boundary values of the MinTypeNameLength, e.g. that `long int` is replaced with `auto` when the option is set to 8 and it stays `long int`with the option set to 9.

Please also add tests with template typenames: e.g. the lenght of `T <  int  >` should be considered 6 and the length of `T  <  const int >` is 12. I guess, the algorithm I proposed will be incorrect for pointer type arguments of templates (the length of `T<int*>` should be 7 regardless of `RemoveStars`), but this can be fixed by conditionally (on RemoveStars) trimming `*`s from the right of the type name and then treating them as punctuation. So instead of

```
  for (const unsigned char C : tooling::fixit::getText(SR, Context)) {
    const CharType NextChar =
        std::isalnum(C)
            ? Alpha
            : (std::isspace(C) || (!RemoveStars && C == '*')) ? Space
                                                              : Punctuation;
```

you could use something similar to

```
  StringRef Text = tooling::fixit::getText(SR, Context);
  if (RemoveStars)
    Text = Text.rtrim(" \t\v\n\r*");
  for (const unsigned char C : Text) {
    const CharType NextChar =
        std::isalnum(C) ? Alpha : std::isspace(C) ? Space : Punctuation;
```


https://reviews.llvm.org/D45927