tree-sitter / tree-sitter/tree-sitter-cpp

bug: Parse error with `>=` operator

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bug
Dominant language
JavaScript
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Description

Did you check existing issues?
  • I have read all the tree-sitter docs if it relates to using the parser
  • I have searched the existing issues of tree-sitter-cpp
Tree-Sitter CLI Version, if relevant (output of tree-sitter --version)

tree-sitter 0.25.3 (2a835ee029dca1c325e6f1c01dbce40396f6123e)

Describe the bug

In the following code snippet

int main() {
    int a = 0, b = 1, c = 2, d = 3, e = 4;

    if (a || (b < c && e >= d)) { /* ... */ }

    return 0;
}

The parse tree does not correctly identify the binary expression e >= d and reports = as the operator instead of >=.
Note that if we replace >= with <=, the error does not occur.

Steps To Reproduce/Bad Parse Tree
  1. Write the code above in the playground Code section.
  2. Observe the obtained parse tree:
translation_unit [0, 0] - [7, 0]
  function_definition [0, 0] - [6, 1]
    type: primitive_type [0, 0] - [0, 3]
    declarator: function_declarator [0, 4] - [0, 10]
      declarator: identifier [0, 4] - [0, 8]
      parameters: parameter_list [0, 8] - [0, 10]
        ( [0, 8] - [0, 9]
        ) [0, 9] - [0, 10]
    body: compound_statement [0, 11] - [6, 1]
      { [0, 11] - [0, 12]
      declaration [1, 4] - [1, 42]
        type: primitive_type [1, 4] - [1, 7]
        declarator: init_declarator [1, 8] - [1, 13]
          declarator: identifier [1, 8] - [1, 9]
          = [1, 10] - [1, 11]
          value: number_literal [1, 12] - [1, 13]
        , [1, 13] - [1, 14]
        declarator: init_declarator [1, 15] - [1, 20]
          declarator: identifier [1, 15] - [1, 16]
          = [1, 17] - [1, 18]
          value: number_literal [1, 19] - [1, 20]
        , [1, 20] - [1, 21]
        declarator: init_declarator [1, 22] - [1, 27]
          declarator: identifier [1, 22] - [1, 23]
          = [1, 24] - [1, 25]
          value: number_literal [1, 26] - [1, 27]
        , [1, 27] - [1, 28]
        declarator: init_declarator [1, 29] - [1, 34]
          declarator: identifier [1, 29] - [1, 30]
          = [1, 31] - [1, 32]
          value: number_literal [1, 33] - [1, 34]
        , [1, 34] - [1, 35]
        declarator: init_declarator [1, 36] - [1, 41]
          declarator: identifier [1, 36] - [1, 37]
          = [1, 38] - [1, 39]
          value: number_literal [1, 40] - [1, 41]
        ; [1, 41] - [1, 42]
      if_statement [3, 4] - [3, 45]
        if [3, 4] - [3, 6]
        condition: condition_clause [3, 7] - [3, 31]
          ( [3, 7] - [3, 8]
          value: binary_expression [3, 8] - [3, 30]
            left: identifier [3, 8] - [3, 9]
            operator: || [3, 10] - [3, 12]
            right: parenthesized_expression [3, 13] - [3, 30]
              ( [3, 13] - [3, 14]
              assignment_expression [3, 14] - [3, 29]
                left: template_function [3, 14] - [3, 26]
                  name: identifier [3, 14] - [3, 15]
                  arguments: template_argument_list [3, 16] - [3, 26]
                    < [3, 16] - [3, 17]
                    binary_expression [3, 18] - [3, 24]
                      left: identifier [3, 18] - [3, 19]
                      operator: && [3, 20] - [3, 22]
                      right: identifier [3, 23] - [3, 24]
                    > [3, 25] - [3, 26]
                operator: = [3, 26] - [3, 27]          <---------- Incorrectly shows = as the operator
                right: identifier [3, 28] - [3, 29]
              ) [3, 29] - [3, 30]
          ) [3, 30] - [3, 31]
        consequence: compound_statement [3, 32] - [3, 45]
          { [3, 32] - [3, 33]
          comment [3, 34] - [3, 43]
          } [3, 44] - [3, 45]
      return_statement [5, 4] - [5, 13]
        return [5, 4] - [5, 10]
        number_literal [5, 11] - [5, 12]
        ; [5, 12] - [5, 13]
      } [6, 0] - [6, 1]
Expected Behavior/Parse Tree

The parse tree should correctly interpret the e >= d binary expression and identify >= as the operator.

Repro
int main() {
    int a = 0, b = 1, c = 2, d = 3, e = 4;

    if (a || (b < c && e >= d)) { /* ... */ }

    return 0;
}

Contributor guide

No contributing guide indexed for this repository

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Reproduce the reported C++ snippet in the Tree-sitter playground and inspect how the grammar parses the nested comparison and assignment expression. The work is done when the parse tree identifies >= as the operator in e >= d, while preserving the existing behavior for the corresponding <= case.

Written by the indexing model from the issue text.

Assessment

Tech stack
cpp
Domain
compilers
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
48/100

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