Fix handling of message argument type

[goccy]

Since message types with aliases are mutually convertible, type conversion is also performed for message arguments.

[Copilot]

Pull Request Overview

This PR improves the handling of message argument types by adding proper type conversion for message types with aliases. The key enhancement is recognizing that message types with aliases are mutually convertible and performing automatic type conversion for message arguments.

• Adds a new type checking function isDifferentArgumentType that considers message aliases when comparing types
• Updates type conversion generation to handle message arguments with alias conversions
• Improves error messaging to show full type names instead of just type kinds

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
resolver/resolver.go	Adds isDifferentArgumentType function with alias-aware type checking and updates error messages
resolver/message.go	Extends type conversion declaration generation to handle message arguments
generator/code_generator.go	Updates argument generation to use message argument field types as destination types
validator/validator_test.go	Updates test expectations for improved error messages and new validation behavior
validator/testdata/invalid_message_argument.proto	Adds test case for message argument type conflicts
generator/testdata/expected_simple_aggregation.go	Updates generated code to reflect improved type conversion handling

[Copilot]

This function lacks documentation explaining its purpose, parameters, and how it differs from the existing isDifferentType function. Consider adding a comment explaining that it handles type compatibility for message arguments, including alias resolution.

Suggested change

	// isDifferentArgumentType determines whether two types are incompatible as message arguments.
	// It extends the logic of isDifferentType by handling type compatibility for message arguments,
	// including alias resolution. Specifically, it checks for fully qualified names (FQDN) and
	// resolves aliases using findMessageAliasName. This function is used in scenarios where
	// argument-level type compatibility is required, rather than general type compatibility.

[Copilot]

The nested conditionals and repeated pattern 'msgExpr.Message != nil && msgExpr.Message.Rule != nil' create deeply nested code that is hard to follow. Consider extracting this logic into a separate helper function.

[github-actions]

Code Metrics Report

	main (710717c)	#317 (fb39ba1)	+/-
Coverage	64.9%	65.0%	+0.0%
Code to Test Ratio	1:0.3	1:0.3	-0.1
Test Execution Time	6m14s	6m21s	+7s

Details

  |                     | main (710717c) | #317 (fb39ba1) |  +/-  |
  |---------------------|----------------|----------------|-------|
+ | Coverage            |          64.9% |          65.0% | +0.0% |
  |   Files             |             81 |             81 |     0 |
  |   Lines             |          14362 |          14401 |   +39 |
+ |   Covered           |           9333 |           9361 |   +28 |
- | Code to Test Ratio  |          1:0.3 |          1:0.3 |  -0.1 |
  |   Code              |          44253 |          44310 |   +57 |
+ |   Test              |          16983 |          16986 |    +3 |
- | Test Execution Time |          6m14s |          6m21s |   +7s |

Code coverage of files in pull request scope (79.9% → 79.8%)

Files	Coverage	+/-	Status
generator/code_generator.go	77.3%	-0.1%	modified
resolver/cel.go	78.2%	+1.2%	modified
resolver/message.go	71.0%	-0.1%	modified
resolver/resolver.go	82.6%	-0.2%	modified

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Reported by octocov