fix(diagnostic): handle constrained generic function calls in call-non-callable

[lewis6991]

call/non-callable analysis treated template refs as definitively
non-callable and did not consistently use template constraints during
callability checks.

Fixes:

• infer_call_expr_func now handles TplRef/ConstTplRef/StrTplRef by
  resolving through get_tpl_ref_extend_type before call inference.
• added a recursion guard when the resolved constraint type is
  unchanged.
• call_non_callable checker now evaluates template refs via their
  constraints in has_non_callable_member.
• union non-callable collection now reuses has_non_callable_member for
  consistent filtering.

[gemini-code-assist]

Summary of Changes

Hello @lewis6991, 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 addresses an issue where the call-non-callable diagnostic incorrectly flagged generic function calls involving template references. The changes enhance the type inference system to properly resolve and evaluate template constraints, ensuring that the diagnostic accurately identifies callable types and avoids false positives for valid generic function usages.

Highlights

• Template Reference Handling: The infer_call_expr_func now correctly processes TplRef, ConstTplRef, and StrTplRef types by resolving their extended types before performing call inference.
• Recursion Guard: A recursion guard has been implemented in the template reference resolution logic to prevent infinite loops when the resolved constraint type remains unchanged.
• Improved Callability Checks: The call_non_callable checker now accurately evaluates template references by considering their constraints within the has_non_callable_member function.
• Consistent Union Type Filtering: The union non-callable collection mechanism now reuses has_non_callable_member for more consistent and accurate filtering of callable types.

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Changelog

• crates/emmylua_code_analysis/src/diagnostic/checker/call_non_callable.rs
  • Modified has_non_callable_member to include logic for TplRef, ConstTplRef, and StrTplRef by checking their constraints.
  • Updated collect_non_callable_union_types to use !has_non_callable_member for filtering, ensuring consistent callability checks.
• crates/emmylua_code_analysis/src/diagnostic/test/call_non_callable_test.rs
  • Added a new test case test_no_call_non_callable_for_generic_function_param_in_a_lua to validate the fix for generic function parameters.
• crates/emmylua_code_analysis/src/semantic/infer/infer_call/mod.rs
  • Imported get_tpl_ref_extend_type for template reference resolution.
  • Extended infer_call_expr_func to handle TplRef, ConstTplRef, and StrTplRef by delegating to a new infer_tpl_ref_call function.
  • Introduced infer_tpl_ref_call function to resolve template references and prevent recursion if the type remains unchanged.

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[gemini-code-assist]

Code Review

This pull request effectively addresses an issue with call analysis on constrained generic functions. The changes in infer_call_expr_func to resolve template references and the corresponding updates in has_non_callable_member are well-implemented and correctly handle template constraints. The addition of a new test case is also a great inclusion. I have one suggestion to improve maintainability by reducing code duplication.