cb.Member: support map type

[xushiwei]

No description provided.

[gemini-code-assist]

Summary of Changes

Hello @xushiwei, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request enhances the code builder's capability to correctly interpret and generate code for map member access. It shifts the mechanism for handling map operations from a generic built-in method approach to a more specific implementation that directly supports indexing into map elements, thereby improving the accuracy and expressiveness of generated code involving maps.

Highlights

• Map Type Handling Refactor: Refactored the internal handling of map types, moving away from treating map methods like Len as generic built-in methods.
• Direct Map Element Access: Introduced explicit support for direct element access on map types (e.g., myMap["key"]) within the cb.Member logic, generating an ast.IndexExpr.
• Removal of Redundant Built-in Map Type Definitions: Removed the tyMap global variable and its associated entries from the initBuiltinTIs and getBuiltinTI functions in builtin.go, as map operations are now handled more specifically.

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[gemini-code-assist]

Code Review

This pull request adds support for accessing map elements using dot notation, e.g., myMap.key. This is a nice syntactic sugar. The implementation correctly generates an index expression for this access. However, it misses a crucial check: it doesn't verify that the map's key type is a string. This could lead to generating invalid Go code for maps with non-string keys. I've added a comment with a suggestion to fix this.

[xgopilot]

Code Review Summary

This PR introduces map member access as syntactic sugar (map.field → map["field"]), which is well-implemented but has critical issues:

Critical:

• ❌ TestBTIMethod fails - breaking change removes map.Len() support
• ⚠️ No key type validation - only works correctly with string-keyed maps

Required:

• Add documentation explaining the new map handling behavior
• Fix or update the failing test
• Validate map key type or document string-key requirement

Positive:

• ✅ Clean implementation with proper type safety for string keys
• ✅ Performance improvement from eliminating BuiltinTI lookups
• ✅ Correct handling of reference flags

[xgopilot]

Code Review Summary

Critical Issues:

1. Test Failure: Removing map.Len() breaks TestBTIMethod - needs immediate attention
2. Missing Type Validation: No check that map keys are strings before generating m["field"] index access

Recommendations:

• Add map key type validation to ensure only string-keyed maps support field-style access
• Either fix the test or implement hybrid behavior for builtin methods like Len()
• Add explanatory comment for the map case in findMember()

Positive Notes:
Performance analysis shows this is a net improvement - eliminates indirection and hash lookups during code generation.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.04%. Comparing base (9e15882) to head (2e863b4).
⚠️ Report is 23 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #580   +/-   ##
=======================================
  Coverage   96.04%   96.04%           
=======================================
  Files          25       25           
  Lines        6819     6833   +14     
=======================================
+ Hits         6549     6563   +14     
  Misses        202      202           
  Partials       68       68           

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