cl: support range over function types (Go 1.23)

[xushiwei]

No description provided.

[gemini-code-assist]

Summary of Changes

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This pull request integrates support for the upcoming Go 1.23 feature that enables for range loops to iterate directly over function types. The changes involve updating the type checking mechanism for for range statements to correctly identify and validate iterator function signatures, ensuring they adhere to the new specification. Additionally, a suite of new tests has been added to verify the functionality across different iterator patterns, from functions yielding no values to those yielding key-value pairs.

Highlights

• Go 1.23 Range Over Functions Support: Implements the new Go 1.23 feature allowing for range loops to iterate over function types, enhancing iteration capabilities.
• Iterator Function Signature Validation: Introduces a new checkIteratorFunc to validate if a function signature conforms to the expected iterator pattern (e.g., func(yield func() bool), func(yield func(V) bool), func(yield func(K, V) bool)).
• Extended for range Type Checking: Modifies the forRangeStmt.check method to include *types.Signature as a valid type for for range statements, delegating validation to checkIteratorFunc.
• Comprehensive Testing: Adds new unit tests (Test_checkIteratorFunc, TestForRangeFunc0, TestForRangeFunc1, TestForRangeFunc2) to cover various scenarios of ranging over functions yielding 0, 1, or 2 values.

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Changelog

• builtin_test.go
  • Added reflect package import for deep equality checks in tests.
  • Introduced Test_checkIteratorFunc to thoroughly test the logic for identifying valid iterator function signatures.
  • Added newParams helper function to simplify the creation of types.Tuple for test cases.
• package_test.go
  • Added TestForRangeFunc0 to verify for range behavior with iterator functions that yield zero values.
  • Added TestForRangeFunc1 to verify for range behavior with iterator functions that yield a single value.
  • Added TestForRangeFunc2 to verify for range behavior with iterator functions that yield two values (key-value pairs).
• stmt.go
  • Modified the forRangeStmt.check method to include a new case *types.Signature, enabling the processing of function types in for range statements.
  • Implemented checkIteratorFunc to determine if a given *types.Signature is a valid Go 1.23 iterator function and to extract the types of the yielded values.

Activity

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.07%. Comparing base (e9785e5) to head (db4a3b7).
⚠️ Report is 6 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #587      +/-   ##
==========================================
+ Coverage   96.06%   96.07%   +0.01%     
==========================================
  Files          25       25              
  Lines        6855     6879      +24     
==========================================
+ Hits         6585     6609      +24     
  Misses        202      202              
  Partials       68       68              

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[gemini-code-assist]

Code Review

This pull request adds support for range over function types, a new feature in Go 1.23. The implementation correctly handles the new case *types.Signature in getKeyValTypes and adds a checkIteratorFunc to validate iterator function signatures. The accompanying tests in package_test.go are well-written and cover the new functionality. However, I've identified a few areas for improvement: the tests for checkIteratorFunc are missing positive cases, there's a misleading comment in checkIteratorFunc, and more importantly, the existing logic for handling for range variables doesn't seem to correctly validate against the number of values produced by function iterators, which could lead to a panic.

[xgopilot]

Code Review Summary

Great work implementing Go 1.23's range over function types! The implementation is clean and follows existing codebase patterns. Found three noteworthy issues:

1. Documentation inaccuracy in checkIteratorFunc (line 629) - comment doesn't match implementation
2. Missing type alias handling in checkIteratorFunc (line 639) - should use typesalias.Unalias() for consistency
3. Test coverage gap - Test_checkIteratorFunc only tests negative cases; needs positive cases for valid iterator signatures

The integration tests are comprehensive, but the unit test should directly verify valid signatures return correct types.