ckandeler added inline comments.

================
Comment at: clang-tools-extra/clangd/SemanticHighlighting.h:76
   ConstructorOrDestructor,
+  UserProvided,
 
----------------
sammccall wrote:
> ckandeler wrote:
> > sammccall wrote:
> > > sammccall wrote:
> > > > nridge wrote:
> > > > > ckandeler wrote:
> > > > > > ckandeler wrote:
> > > > > > > sammccall wrote:
> > > > > > > > sammccall wrote:
> > > > > > > > > sammccall wrote:
> > > > > > > > > > Can you give some background here or on the bug tracker 
> > > > > > > > > > about what kind of distinction you're trying to draw here 
> > > > > > > > > > and why it's important?
> > > > > > > > > > (Most clients are never going to benefit from nonstandard 
> > > > > > > > > > modifiers so they should be pretty compelling)
> > > > > > > > > as well as being jargony, "user-provided" has a specific 
> > > > > > > > > technical meaning that I don't think you intend here. For 
> > > > > > > > > example, `auto operator<=>(const S&) const = default` is not 
> > > > > > > > > user-provided (defaulted on first declaration). 
> > > > > > > > > https://eel.is/c++draft/dcl.fct.def.default#5
> > > > > > > > > 
> > > > > > > > > If we need this and can't get away with reusing 
> > > > > > > > > `defaultLibrary` (which would include `std::`) then maybe we 
> > > > > > > > > should add something like `builtin` which seems quite 
> > > > > > > > > reusable.
> > > > > > > > Since we often can't say whether an operator is user-provided 
> > > > > > > > or not (in templates), we should consider what we want the 
> > > > > > > > highlighting to be in these cases.
> > > > > > > > (If templates should be highlighted as built-in, we should 
> > > > > > > > prefer a modifier like `UserProvided`, if they should be 
> > > > > > > > highlighted as user-provided, we should prefer a modifier like 
> > > > > > > > `Builtin`)
> > > > > > > > as well as being jargony, "user-provided" has a specific 
> > > > > > > > technical meaning that I don't think you intend here. For 
> > > > > > > > example, `auto operator<=>(const S&) const = default` is not 
> > > > > > > > user-provided (defaulted on first declaration). 
> > > > > > > > https://eel.is/c++draft/dcl.fct.def.default#5
> > > > > > > > 
> > > > > > > > If we need this and can't get away with reusing 
> > > > > > > > `defaultLibrary` (which would include `std::`) then maybe we 
> > > > > > > > should add something like `builtin` which seems quite reusable.
> > > > > > > 
> > > > > > > I use "userProvided" here in the sense of "not built-in" or 
> > > > > > > "overloaded". I do not cling to the term, and have also suggested 
> > > > > > > the opposite default of using "builtin" in another comment.
> > > > > > > Since we often can't say whether an operator is user-provided or 
> > > > > > > not (in templates), we should consider what we want the 
> > > > > > > highlighting to be in these cases.
> > > > > > 
> > > > > > True, I have not considered this.
> > > > > > 
> > > > > > > (If templates should be highlighted as built-in, we should prefer 
> > > > > > > a modifier like `UserProvided`, if they should be highlighted as 
> > > > > > > user-provided, we should prefer a modifier like `Builtin`)
> > > > > > 
> > > > > > Intuitively, it seems we should be conservative and not claim the 
> > > > > > operator is overloaded unless we know it is. So "built-in" might 
> > > > > > then mean "we can't prove it's not a built-in". It's probably not 
> > > > > > worth to introduce a modifier CouldBeEitherWay just to explicitly 
> > > > > > express ambiguity ;)
> > > > > > Since we often can't say whether an operator is user-provided or 
> > > > > > not (in templates), we should consider what we want the 
> > > > > > highlighting to be in these cases.
> > > > > > (If templates should be highlighted as built-in, we should prefer a 
> > > > > > modifier like `UserProvided`, if they should be highlighted as 
> > > > > > user-provided, we should prefer a modifier like `Builtin`)
> > > > > 
> > > > > In my mind, "go-to-definition on this operator symbol will take me to 
> > > > > a function declaration/definition" is a good match for "I want this 
> > > > > colored differently". (Which would imply treating dependent operator 
> > > > > calls where we can't figure out an overloaded operator target even 
> > > > > heuristically, as "built-in".)
> > > > > Can you give some background here or on the bug tracker about what 
> > > > > kind of distinction you're trying to draw here and why it's important?
> > > > > (Most clients are never going to benefit from nonstandard modifiers 
> > > > > so they should be pretty compelling)
> > > > 
> > > > This was one of the biggest questions I had about this patch - just 
> > > > hoping it doesn't get missed.
> > > > Intuitively, it seems we should be conservative and not claim the 
> > > > operator is overloaded unless we know it is. 
> > > 
> > > This feels a bit circular, if we agree we're not going to introduce a 
> > > `CouldBeEitherWay` then why is "built-in" a more conservative claim than 
> > > "overloaded"?
> > > 
> > > I'm inclined towards `builtin` as a modifier because I think for language 
> > > entities as a whole (types, functions etc, not just operators) it's the 
> > > exception. It also seems easier to name and define.
> > > 
> > > > In my mind, "go-to-definition on this operator symbol will take me to a 
> > > > function declaration/definition" is a good match for "I want this 
> > > > colored differently".
> > > 
> > > This mostly makes sense to me, but:
> > >  - I don't think we should actually run all the heuristics logic
> > >  - if there's probably a definition available but we can't resolve it due 
> > > to templates, I'd still like to know something's up
> > > 
> > > I think my internal question is more like "is this a trivial arithmetic 
> > > shift, or something potentially complicated"? And I think depending on 
> > > template resolution is "potentially complicated". (Maybe trivial in the 
> > > end, but so might be an overloaded operator)
> > > > Intuitively, it seems we should be conservative and not claim the 
> > > > operator is overloaded unless we know it is. 
> > > 
> > > This feels a bit circular, if we agree we're not going to introduce a 
> > > `CouldBeEitherWay` then why is "built-in" a more conservative claim than 
> > > "overloaded"?
> > > 
> > > I'm inclined towards `builtin` as a modifier because I think for language 
> > > entities as a whole (types, functions etc, not just operators) it's the 
> > > exception. It also seems easier to name and define.
> > > 
> > > > In my mind, "go-to-definition on this operator symbol will take me to a 
> > > > function declaration/definition" is a good match for "I want this 
> > > > colored differently".
> > > 
> > > This mostly makes sense to me, but:
> > >  - I don't think we should actually run all the heuristics logic
> > >  - if there's probably a definition available but we can't resolve it due 
> > > to templates, I'd still like to know something's up
> > > 
> > > I think my internal question is more like "is this a trivial arithmetic 
> > > shift, or something potentially complicated"? And I think depending on 
> > > template resolution is "potentially complicated". (Maybe trivial in the 
> > > end, but so might be an overloaded operator)
> > 
> > The documentation for BinaryOperator says:  
> > /// Within a C++ template, whether BinaryOperator or CXXOperatorCallExpr is
> > /// used to store an expression "x + y" depends on the subexpressions
> > /// for x and y. If neither x or y is type-dependent, and the "+"
> > /// operator resolves to a built-in operation, BinaryOperator will be
> > /// used to express the computation (x and y may still be
> > /// value-dependent). If either x or y is type-dependent, or if the
> > /// "+" resolves to an overloaded operator, CXXOperatorCallExpr will
> > /// be used to express the computation.
> > With the patch as-is (possibly with the UserProvided/BuiltIn switch) , this 
> > should result exactly in what you want (if I understand you correctly). 
> > However, it does not match my observation: I always see the normal operator 
> > types. Am I missing something or is the documentation wrong?
> Can you reduce this to an example where `clang -fsyntax-only -Xclang 
> -ast-dump` doesn't print what you expect?
> 
> (if this isn't possible, then it might be a bug in the patch)
$ cat test.cpp
template<typename T> class MyTemplate {
    void run(typename T::A t1, typename T::A t2) { return t1 == t2; }
}
$ clang -fsyntax-only -Xclang -ast-dump test.cpp

TranslationUnitDecl 0x55986dab0dd8 <<invalid sloc>> <invalid sloc>
|-TypedefDecl 0x55986dab1640 <<invalid sloc>> <invalid sloc> implicit 
__int128_t '__int128'
| `-BuiltinType 0x55986dab13a0 '__int128'
|-TypedefDecl 0x55986dab16b0 <<invalid sloc>> <invalid sloc> implicit 
__uint128_t 'unsigned __int128'
| `-BuiltinType 0x55986dab13c0 'unsigned __int128'
|-TypedefDecl 0x55986dab1a28 <<invalid sloc>> <invalid sloc> implicit 
__NSConstantString '__NSConstantString_tag'
| `-RecordType 0x55986dab17a0 '__NSConstantString_tag'
|   `-CXXRecord 0x55986dab1708 '__NSConstantString_tag'
|-TypedefDecl 0x55986dab1ac0 <<invalid sloc>> <invalid sloc> implicit 
__builtin_ms_va_list 'char *'
| `-PointerType 0x55986dab1a80 'char *'
|   `-BuiltinType 0x55986dab0e80 'char'
|-TypedefDecl 0x55986daf65a8 <<invalid sloc>> <invalid sloc> implicit 
__builtin_va_list '__va_list_tag[1]'
| `-ConstantArrayType 0x55986daf6550 '__va_list_tag[1]' 1 
|   `-RecordType 0x55986dab1bb0 '__va_list_tag'
|     `-CXXRecord 0x55986dab1b18 '__va_list_tag'
`-ClassTemplateDecl 0x55986daf6750 <test.cpp:1:1, line:3:1> line:1:28 MyTemplate
  |-TemplateTypeParmDecl 0x55986daf6600 <col:10, col:19> col:19 typename depth 
0 index 0 T
  `-CXXRecordDecl 0x55986daf66c0 <col:22, line:3:1> line:1:28 class MyTemplate 
definition
    |-DefinitionData empty aggregate standard_layout trivially_copyable pod 
trivial literal has_constexpr_non_copy_move_ctor can_const_default_init
    | |-DefaultConstructor exists trivial constexpr needs_implicit 
defaulted_is_constexpr
    | |-CopyConstructor simple trivial has_const_param needs_implicit 
implicit_has_const_param
    | |-MoveConstructor exists simple trivial needs_implicit
    | |-CopyAssignment simple trivial has_const_param needs_implicit 
implicit_has_const_param
    | |-MoveAssignment exists simple trivial needs_implicit
    | `-Destructor simple irrelevant trivial needs_implicit
    |-CXXRecordDecl 0x55986daf6990 <col:22, col:28> col:28 implicit class 
MyTemplate
    `-CXXMethodDecl 0x55986daf6d18 <line:2:5, col:73> col:10 compare 'bool 
(typename T::A, typename T::A)'
      |-ParmVarDecl 0x55986daf6b10 <col:18, col:32> col:32 referenced t1 
'typename T::A'
      |-ParmVarDecl 0x55986daf6bd0 <col:36, col:50> col:50 referenced t2 
'typename T::A'
      `-CompoundStmt 0x55986daf6e50 <col:54, col:73>
        `-ReturnStmt 0x55986daf6e40 <col:56, col:69>
          `-BinaryOperator 0x55986daf6e20 <col:63, col:69> '<dependent type>' 
'=='
            |-DeclRefExpr 0x55986daf6de0 <col:63> 'typename T::A' lvalue 
ParmVar 0x55986daf6b10 't1' 'typename T::A'
            `-DeclRefExpr 0x55986daf6e00 <col:69> 'typename T::A' lvalue 
ParmVar 0x55986daf6bd0 't2' 'typename T::A'




Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D136594/new/

https://reviews.llvm.org/D136594

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