refactor(map): align op_get with array

[peter-jerry-ye]

Closes #1332

[peter-jerry-ye-code-review]

HashMap op_get implementation may have incorrect probe sequence length check

Category
Correctness
Code Snippet
guard i <= entry.psl // in hashmap/linked_hash_map.mbt
Recommendation
Change to guard entry.psl >= i to match hashmap.mbt implementation
Reasoning
The probe sequence length (PSL) check seems reversed compared to the implementation in hashmap.mbt which uses guard entry.psl >= i. Having inconsistent PSL checks could lead to incorrect probing behavior.

Missing documentation for Map::op_get panic behavior

Category
Maintainability
Code Snippet
fn[K : Hash + Eq, V] Map::op_get(Self[K, V], K) -> V // in builtin.mbti
Recommendation
Add documentation comment explaining that op_get panics when key doesn't exist
Reasoning
The breaking change from optional to non-optional return type needs to be clearly documented since it introduces panic behavior. This helps prevent runtime errors from misuse.

Test case pattern `guard m is { ... }` could be more exhaustive

Category
Maintainability
Code Snippet
guard m is { "a": 1, "b": 2, "c": 3, "d"? : None, .. }
Recommendation
Add more cases testing different combinations of existing/non-existing keys
Reasoning
The new pattern matching syntax for maps is a significant feature but current tests only verify basic cases. More comprehensive tests would help ensure correctness of the implementation.

[coveralls]

Pull Request Test Coverage Report for Build 7424

Details

• 24 of 26 (92.31%) changed or added relevant lines in 4 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.006%) to 90.102%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
builtin/linked_hash_map.mbt	4	5	80.0%
hashmap/hashmap.mbt	4	5	80.0%

Totals
Change from base Build 7423:	0.006%
Covered Lines:	8548
Relevant Lines:	9487

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💛 - Coveralls

[bobzhang]

I suggest we hold on this for 2 weeks to have AI updating most existing libs