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templated lambda recognized as compare type #4242

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lceWolf opened this issue Feb 12, 2024 · 5 comments
Open

templated lambda recognized as compare type #4242

lceWolf opened this issue Feb 12, 2024 · 5 comments
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C++20

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@lceWolf
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lceWolf commented Feb 12, 2024

Uncrustify version: 0.78.1

Issue

C++20's templated lambdas are not parsed correctly. Given the following code

int main()
{
    auto t = []<typename T>(T t)
    {
        return t;
    };
}

The template part <typename T> is parsed as a part of a comparison (see debug output below).
This has the effect that if sp_compare is set to force, the template part is formatted as follows:
[] < typename T > (T t)

Expected

The template part is recognized correctly and is independent of sp_compare.

Maybe a new option has to be added for controlling newlines for these templates to distinguish function templates and templated lambdas?

Debug output

# language                      = CPP
# -=====-
# Line                Tag         Parent_type  Type of the parent         Columns Br/Lvl/pp             Flags   Nl  Text
#   1>            NEWLINE|               NONE|     PARENT_NOT_SET[  1/  1/  1/  0][0/0/0][                  0][1-0]
#   2>               TYPE|           FUNC_DEF|     PARENT_NOT_SET[  1/  1/  4/  0][0/0/0][             e 0000][0-0] int
#   2>           FUNC_DEF|               NONE|     PARENT_NOT_SET[  5/  5/  9/  1][0/0/0][                  0][0-0]     main
#   2>        FPAREN_OPEN|           FUNC_DEF|     PARENT_NOT_SET[  9/  9/ 10/  0][0/0/0][        2 0000 0000][0-0]         (
#   2>       FPAREN_CLOSE|           FUNC_DEF|     PARENT_NOT_SET[ 10/ 10/ 11/  0][0/0/0][        2 0000 0008][0-0]          )
#   2>            NEWLINE|               NONE|     PARENT_NOT_SET[ 11/ 11/  1/  0][0/0/0][                  0][1-0]
#   3>         BRACE_OPEN|           FUNC_DEF|     PARENT_NOT_SET[  1/  1/  2/  0][0/0/0][        2 0000 0000][0-0] {
#   3>            NEWLINE|               NONE|     PARENT_NOT_SET[  2/  2/  5/  0][1/1/0][                  0][1-0]
#   4>               TYPE|               NONE|     PARENT_NOT_SET[  5/  5/  9/  0][1/1/0][          208e 0000][0-0]     auto
#   4>               WORD|               NONE|     PARENT_NOT_SET[ 10/ 10/ 11/  1][1/1/0][          2300 0000][0-0]          t
#   4>             ASSIGN|               NONE|     PARENT_NOT_SET[ 12/ 12/ 13/  1][1/1/0][        2 0000 0000][0-0]            =
#   4>            TSQUARE|               NONE|     PARENT_NOT_SET[ 14/ 14/ 16/  1][1/1/0][        2 0008 0000][0-0]              []
#   4>            COMPARE|               NONE|     PARENT_NOT_SET[ 17/ 17/ 18/  1][1/1/0][        2 0000 0000][0-0]                 <
#   4>               TYPE|               NONE|     PARENT_NOT_SET[ 19/ 19/ 25/  1][1/1/0][             a 0000][0-0]                   size_t
#   4>               WORD|               NONE|     PARENT_NOT_SET[ 26/ 26/ 27/  1][1/1/0][                  0][0-0]                          T
#   4>            COMPARE|               NONE|     PARENT_NOT_SET[ 28/ 28/ 29/  1][1/1/0][        2 0000 0000][0-0]                            >
#   4>         PAREN_OPEN|             C_CAST|     PARENT_NOT_SET[ 30/ 30/ 31/  1][1/1/0][        2 0008 0000][0-0]                              (
#   4>               TYPE|             C_CAST|     PARENT_NOT_SET[ 31/ 31/ 32/  0][1/2/0][             a 0000][0-0]                               T
#   4>               TYPE|             C_CAST|     PARENT_NOT_SET[ 33/ 33/ 34/  1][1/2/0][                  0][0-0]                                 t
#   4>        PAREN_CLOSE|             C_CAST|     PARENT_NOT_SET[ 34/ 34/ 35/  0][1/1/0][        2 0000 0000][0-0]                                  )
#   4>            NEWLINE|               NONE|     PARENT_NOT_SET[ 35/ 35/  5/  0][1/1/0][                  0][1-0]
#   5>         BRACE_OPEN|             C_CAST|     PARENT_NOT_SET[  5/  5/  6/  0][1/1/0][        2 0008 0000][0-0]     {
#   5>            NEWLINE|               NONE|     PARENT_NOT_SET[  6/  6/  9/  0][2/2/0][                  0][1-0]
#   6>             RETURN|               NONE|     PARENT_NOT_SET[  9/  9/ 15/  0][2/2/0][             e 0000][0-0]         return
#   6>               WORD|               NONE|     PARENT_NOT_SET[ 16/ 16/ 17/  1][2/2/0][             8 0000][0-0]                t
#   6>          SEMICOLON|               NONE|     PARENT_NOT_SET[ 17/ 17/ 18/  0][2/2/0][        2 0000 0000][0-0]                 ;
#   6>            NEWLINE|               NONE|     PARENT_NOT_SET[ 18/ 18/  5/  0][2/2/0][                  0][1-0]
#   7>        BRACE_CLOSE|             C_CAST|     PARENT_NOT_SET[  5/  5/  6/  0][1/1/0][        2 0000 0000][0-0]     }
#   7>          SEMICOLON|               NONE|     PARENT_NOT_SET[  6/  6/  7/  0][1/1/0][        2 0000 0000][0-0]      ;
#   7>            NEWLINE|               NONE|     PARENT_NOT_SET[  7/  7/  1/  0][1/1/0][                  0][1-0]
#   8>        BRACE_CLOSE|           FUNC_DEF|     PARENT_NOT_SET[  1/  1/  2/  0][0/0/0][        2 0000 0000][0-0] }
#   8>            NEWLINE|               NONE|     PARENT_NOT_SET[  2/  2/  1/  0][0/0/0][                  0][1-0]
# -=====-
@guy-maurel
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Is the template part recognized correctly?
What is about the change from typename to size_t?
I get with clang -Xclang -ast-dump -fsyntax-only lceWolf.cpp

lceWolf.cpp:4:16: warning: explicit template parameter list for lambdas is a C++20 extension [-Wc++20-extensions]
    auto t = []<typename T>(T t)
               ^

Can you provide a compileable source?

@gmaurel gmaurel added the C++20 label Feb 20, 2024
@lceWolf
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lceWolf commented Feb 23, 2024

Thanks for your reply!

Yes the template seems to be recognized correctly. (see the new debug output below).
I don't know what happened to the output, honestly. Looks like I messed something up. Very sorry for that!

New Debug ouput

# Uncrustify_d-0.78.1
# option(s) with 'not default' value: 0
#
# -=====-
# number of loops               = 0
# -=====-
# language                      = CPP
# -=====-
# Line                Tag         Parent_type  Type of the parent         Columns Br/Lvl/pp             Flags   Nl  Text
#   1>               TYPE|           FUNC_DEF|     PARENT_NOT_SET[  1/  1/  4/  0][0/0/0][             e 0000][0-0] int
#   1>           FUNC_DEF|               NONE|     PARENT_NOT_SET[  5/  5/  9/  1][0/0/0][                  0][0-0]     main
#   1>        FPAREN_OPEN|           FUNC_DEF|     PARENT_NOT_SET[  9/  9/ 10/  0][0/0/0][        2 0000 0000][0-0]         (
#   1>       FPAREN_CLOSE|           FUNC_DEF|     PARENT_NOT_SET[ 10/ 10/ 11/  0][0/0/0][        2 0000 0008][0-0]          )
#   1>            NEWLINE|               NONE|     PARENT_NOT_SET[ 11/ 11/  1/  0][0/0/0][                  0][1-0]
#   2>         BRACE_OPEN|           FUNC_DEF|     PARENT_NOT_SET[  1/  1/  2/  0][0/0/0][        2 0000 0000][0-0] {
#   2>            NEWLINE|               NONE|     PARENT_NOT_SET[  2/  2/  5/  0][1/1/0][                  0][1-0]
#   3>               TYPE|               NONE|     PARENT_NOT_SET[  9/  5/  9/  0][1/1/0][          208e 0000][0-0]         auto
#   3>               WORD|               NONE|     PARENT_NOT_SET[ 14/ 10/ 11/  1][1/1/0][          2300 0000][0-0]              t
#   3>             ASSIGN|               NONE|     PARENT_NOT_SET[ 16/ 12/ 13/  1][1/1/0][        2 0000 0000][0-0]                =
#   3>            TSQUARE|               NONE|     PARENT_NOT_SET[ 18/ 14/ 16/  1][1/1/0][        2 0008 0000][0-0]                  []
#   3>            COMPARE|               NONE|     PARENT_NOT_SET[ 20/ 16/ 17/  0][1/1/0][        2 0000 0000][0-0]                    <
#   3>           TYPENAME|               NONE|     PARENT_NOT_SET[ 21/ 17/ 25/  0][1/1/0][             a 0000][0-0]                     typename
#   3>               WORD|               NONE|     PARENT_NOT_SET[ 30/ 26/ 27/  1][1/1/0][                  0][0-0]                              T
#   3>            COMPARE|               NONE|     PARENT_NOT_SET[ 31/ 27/ 28/  0][1/1/0][        2 0000 0000][0-0]                               >
#   3>         PAREN_OPEN|             C_CAST|     PARENT_NOT_SET[ 32/ 28/ 29/  0][1/1/0][        2 0008 0000][0-0]                                (
#   3>               TYPE|             C_CAST|     PARENT_NOT_SET[ 33/ 29/ 30/  0][1/2/0][             a 0000][0-0]                                 T
#   3>               TYPE|             C_CAST|     PARENT_NOT_SET[ 35/ 31/ 32/  1][1/2/0][                  0][0-0]                                   t
#   3>        PAREN_CLOSE|             C_CAST|     PARENT_NOT_SET[ 36/ 32/ 33/  0][1/1/0][        2 0000 0000][0-0]                                    )
#   3>            NEWLINE|               NONE|     PARENT_NOT_SET[ 37/ 33/  5/  0][1/1/0][                  0][1-0]
#   4>         BRACE_OPEN|             C_CAST|     PARENT_NOT_SET[  9/  5/  6/  0][1/1/0][        2 0008 0000][0-0]         {
#   4>            NEWLINE|               NONE|     PARENT_NOT_SET[ 10/  6/  9/  0][2/2/0][                  0][1-0]
#   5>             RETURN|               NONE|     PARENT_NOT_SET[ 17/  9/ 15/  0][2/2/0][             e 0000][0-0]                 return
#   5>               WORD|               NONE|     PARENT_NOT_SET[ 24/ 16/ 17/  1][2/2/0][             8 0000][0-0]                        t
#   5>          SEMICOLON|               NONE|     PARENT_NOT_SET[ 25/ 17/ 18/  0][2/2/0][        2 0000 0000][0-0]                         ;
#   5>            NEWLINE|               NONE|     PARENT_NOT_SET[ 26/ 18/  5/  0][2/2/0][                  0][1-0]
#   6>        BRACE_CLOSE|             C_CAST|     PARENT_NOT_SET[  9/  5/  6/  0][1/1/0][        2 0000 0000][0-0]         }
#   6>          SEMICOLON|               NONE|     PARENT_NOT_SET[ 10/  6/  7/  0][1/1/0][        2 0000 0000][0-0]          ;
#   6>            NEWLINE|               NONE|     PARENT_NOT_SET[ 11/  7/  1/  0][1/1/0][                  0][1-0]
#   7>        BRACE_CLOSE|           FUNC_DEF|     PARENT_NOT_SET[  1/  1/  2/  0][0/0/0][        2 0000 0000][0-0] }
#   7>            NEWLINE|               NONE|     PARENT_NOT_SET[  2/  2/  1/  0][0/0/0][                  0][2-0]
# -=====-

Compile

using clang++ -Xclang -ast-dump -fsyntax-only lceWolf.cpp -std=c++20 it compiles fine and results in

TranslationUnitDecl 0x15fc198 <<invalid sloc>> <invalid sloc>
|-TypedefDecl 0x15fca20 <<invalid sloc>> <invalid sloc> implicit __int128_t '__int128'
| `-BuiltinType 0x15fc760 '__int128'
|-TypedefDecl 0x15fca98 <<invalid sloc>> <invalid sloc> implicit __uint128_t 'unsigned __int128'
| `-BuiltinType 0x15fc780 'unsigned __int128'
|-TypedefDecl 0x15fce50 <<invalid sloc>> <invalid sloc> implicit __NSConstantString '__NSConstantString_tag'
| `-RecordType 0x15fcba0 '__NSConstantString_tag'
|   `-CXXRecord 0x15fcaf8 '__NSConstantString_tag'
|-TypedefDecl 0x15fcef8 <<invalid sloc>> <invalid sloc> implicit __builtin_ms_va_list 'char *'
| `-PointerType 0x15fceb0 'char *'
|   `-BuiltinType 0x15fc240 'char'
|-TypedefDecl 0x1646ea0 <<invalid sloc>> <invalid sloc> implicit __builtin_va_list '__va_list_tag[1]'
| `-ConstantArrayType 0x1646e40 '__va_list_tag[1]' 1 
|   `-RecordType 0x15fd000 '__va_list_tag'
|     `-CXXRecord 0x15fcf58 '__va_list_tag'
`-FunctionDecl 0x1646f58 <lceWolf.cpp:1:1, line:7:1> line:1:5 main 'int ()'
  `-CompoundStmt 0x1679420 <line:2:1, line:7:1>
    `-DeclStmt 0x1679408 <line:3:5, line:6:6>
      `-VarDecl 0x1647108 <line:3:5, line:6:5> line:3:10 t '(lambda at lceWolf.cpp:3:14)':'(lambda at lceWolf.cpp:3:14)' cinit
        `-LambdaExpr 0x1647ca8 <col:14, line:6:5> '(lambda at lceWolf.cpp:3:14)'
          |-CXXRecordDecl 0x1647398 <line:3:14> col:14 implicit class definition
          | |-DefinitionData generic lambda pass_in_registers empty standard_layout trivially_copyable 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 constexpr
          | |-FunctionTemplateDecl 0x16476c0 <<invalid sloc>, line:6:5> line:3:14 operator()
          | | |-TemplateTypeParmDecl 0x1647178 <col:17, col:26> col:26 referenced typename depth 0 index 0 T
          | | `-CXXMethodDecl 0x1647608 <col:32, line:6:5> line:3:14 constexpr operator() 'auto (T) const' inline
          | |   |-ParmVarDecl 0x1647240 <col:29, col:31> col:31 referenced t 'T'
          | |   `-CompoundStmt 0x16477d8 <line:4:5, line:6:5>
          | |     `-ReturnStmt 0x16477c8 <line:5:9, col:16>
          | |       `-DeclRefExpr 0x16477a8 <col:16> 'T' lvalue ParmVar 0x1647240 't' 'T'
          | |-FunctionTemplateDecl 0x1647b20 <<invalid sloc>, line:6:5> line:3:14 implicit operator auto (*)(type-parameter-0-0)
          | | |-TemplateTypeParmDecl 0x1647178 <col:17, col:26> col:26 referenced typename depth 0 index 0 T
          | | `-CXXConversionDecl 0x1647a70 <col:14, line:6:5> line:3:14 implicit constexpr operator auto (*)(type-parameter-0-0) 'auto (*() const noexcept)(T)' inline
          | |-FunctionTemplateDecl 0x1647c38 <<invalid sloc>, line:6:5> line:3:14 implicit __invoke
          | | |-TemplateTypeParmDecl 0x1647178 <col:17, col:26> col:26 referenced typename depth 0 index 0 T
          | | `-CXXMethodDecl 0x1647b88 <col:14, line:6:5> line:3:14 implicit __invoke 'auto (T)' static inline
          | |   `-ParmVarDecl 0x1647a00 <col:29, col:31> col:31 t 'T'
          | `-CXXDestructorDecl 0x1647cd8 <col:14> col:14 implicit referenced constexpr ~ 'void () noexcept' inline default trivial
          `-CompoundStmt 0x16477d8 <line:4:5, line:6:5>
            `-ReturnStmt 0x16477c8 <line:5:9, col:16>
              `-DeclRefExpr 0x16477a8 <col:16> 'T' lvalue ParmVar 0x1647240 't' 'T'

@guy-maurel
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can you close?

@lceWolf
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lceWolf commented Mar 4, 2024

I just tested with the latest master (Uncrustify-0.78.1-143-d2b66ae86) and the issue seems to still be present.
If sp_compare is set to force the file is still wrongly formatted

@lceWolf
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lceWolf commented Apr 18, 2024

@guy-maurel I don't want to push, I just want to make sure that all the necessary information is available. So, is anything still missing?

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@lceWolf @gmaurel @guy-maurel