text: <===> parent/input.scss
  a {b: selector-parse("&")}
  
  <===> parent/error
  Error: $selector: Parent selectors aren't allowed here.
    ,
  1 | &
    | ^
    '
    - 1:1  root stylesheet
    ,
  1 | a {b: selector-parse("&")}
    |       ^^^^^^^^^^^^^^^^^^^
    '
    input.scss 1:7  root stylesheet
  
  <===> parent/error-libsass
  Error: Parent selectors aren't allowed here.
          on line 1:22 of input.scss, in function `selector-parse`
          from line 1:7 of input.scss
  >> a {b: selector-parse("&")}
  
     ---------------------^
  
  <===>
  ================================================================================
  <===> parse/invalid/input.scss
  a {b: selector-parse("[c")}
  
  <===> parse/invalid/error
  Error: $selector: expected more input.
    ,
  1 | [c
    |   ^
    '
    - 1:3  root stylesheet
    ,
  1 | a {b: selector-parse("[c")}
    |       ^^^^^^^^^^^^^^^^^^^^
    '
    input.scss 1:7  root stylesheet
  
  <===> parse/invalid/error-libsass
  Error: invalid operator in attribute selector for c
          on line 1:23 of input.scss, in function `selector-parse`
          from line 1:7 of input.scss
  >> a {b: selector-parse("[c")}
  
     ----------------------^
  
  <===>
  ================================================================================
  <===> parse/extra/options.yml
  ---
  :todo:
  - sass/libsass#2965
  
  <===> parse/extra/input.scss
  a {b: selector-parse("c {")}
  
  <===> parse/extra/error
  Error: $selector: expected selector.
    ,
  1 | c {
    |   ^
    '
    - 1:3  root stylesheet
    ,
  1 | a {b: selector-parse("c {")}
    |       ^^^^^^^^^^^^^^^^^^^^^
    '
    input.scss 1:7  root stylesheet
  
  <===>
  ================================================================================
  <===> too_nested/options.yml
  ---
  :todo:
  - sass/libsass#2964
  
  <===> too_nested/input.scss
  a {b: selector-parse((append((), append((), c)),))}
  
  <===> too_nested/error
  Error: c is not a valid selector: it must be a string,
  a list of strings, or a list of lists of strings.
    ,
  1 | a {b: selector-parse((append((), append((), c)),))}
    |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    '
    input.scss 1:7  root stylesheet
  
  <===>
  ================================================================================
  <===> inner_comma/options.yml
  ---
  :todo:
  - sass/libsass#2964
  
  <===> inner_comma/input.scss
  a {b: selector-parse(((c,),))}
  
  <===> inner_comma/error
  Error: $selector: ((c,),) is not a valid selector: it must be a string,
  a list of strings, or a list of lists of strings.
    ,
  1 | a {b: selector-parse(((c,),))}
    |       ^^^^^^^^^^^^^^^^^^^^^^^
    '
    input.scss 1:7  root stylesheet
  
  <===>
  ================================================================================
  <===> outer_space/options.yml
  ---
  :todo:
  - sass/libsass#2964
  
  <===> outer_space/input.scss
  a {b: selector-parse(append((), append((), c)))}
  
  <===> outer_space/error
  Error: $selector: c is not a valid selector: it must be a string,
  a list of strings, or a list of lists of strings.
    ,
  1 | a {b: selector-parse(append((), append((), c)))}
    |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    '
    input.scss 1:7  root stylesheet
  
  <===>
  ================================================================================
  <===> type/options.yml
  ---
  :todo:
  - sass/libsass#2964
  
  <===> type/input.scss
  a {b: selector-parse(1)}
  
  <===> type/error
  Error: $selector: 1 is not a valid selector: it must be a string,
  a list of strings, or a list of lists of strings.
    ,
  1 | a {b: selector-parse(1)}
    |       ^^^^^^^^^^^^^^^^^
    '
    input.scss 1:7  root stylesheet
  
  <===>
  ================================================================================
  <===> too_many_args/input.scss
  a {b: selector-parse(c, d)}
  
  <===> too_many_args/error
  Error: Only 1 argument allowed, but 2 were passed.
    ,--> input.scss
  1 | a {b: selector-parse(c, d)}
    |       ^^^^^^^^^^^^^^^^^^^^ invocation
    '
    ,--> sass:selector
  1 | @function parse($selector) {
    |           ================ declaration
    '
    input.scss 1:7  root stylesheet
  
  <===> too_many_args/error-libsass
  Error: wrong number of arguments (2 for 1) for `selector-parse'
          on line 1:7 of input.scss
  >> a {b: selector-parse(c, d)}
  
     ------^
  
  <===>
  ================================================================================
  <===> too_few_args/input.scss
  a {b: selector-parse()}
  
  <===> too_few_args/error
  Error: Missing argument $selector.
    ,--> input.scss
  1 | a {b: selector-parse()}
    |       ^^^^^^^^^^^^^^^^ invocation
    '
    ,--> sass:selector
  1 | @function parse($selector) {
    |           ================ declaration
    '
    input.scss 1:7  root stylesheet
  
  <===> too_few_args/error-libsass
  Error: Function selector-parse is missing argument $selector.
          on line 1 of input.scss
  >> a {b: selector-parse()}
  
     ------^
  