Fix NotImplementedError when constructing a cross containing wildcard bins

[Copilot]

CoverpointBinSingleWildcardModel never implemented get_bin_range(), so constructing any vsc.cross that references a coverpoint with wildcard_bin entries crashed during _build_ignore_map() finalization.

@vsc.covergroup
class Cg:
    def __init__(self):
        self.with_sample(dict(it=Item()))
        self.wildcard_cp = vsc.coverpoint(
            self.it.x,
            bins={"low": vsc.wildcard_bin("0b0???????"), "high": vsc.wildcard_bin("0b1???????")}
        )
        self.plain_cp = vsc.coverpoint(self.it.y, bins={"a": vsc.bin([0, 127]), "b": vsc.bin([128, 255])})
        self.cross = vsc.cross([self.wildcard_cp, self.plain_cp])  # raised NotImplementedError

Changes

• CoverpointBinSingleWildcardModel.get_bin_range() — implements the missing method by iterating over wildcard_binspec.specs and expanding each (value, mask) pair into concrete (low, high) ranges via WildcardBinFactory.valmask2binlist(), returning them as a combined tuple. Consistent with the single-bin contract (n_bins = 1) shared by CoverpointBinSingleRangeModel and CoverpointBinSingleValModel.

• test_coverage_cross.test_cross_with_wildcard_bins — adds a regression test covering the exact failure scenario: a cross between a wildcard-binned and a plain-binned coverpoint, verifying construction succeeds and the cross produces the correct 4-bin structure.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>NotImplementedError when defining a cross that contains a coverpoint with wildcard bins</issue_title>
<issue_description>### Description

Defining a vsc.cross that includes a coverpoint using vsc.wildcard_bin raises a NotImplementedError during covergroup construction. The crash occurs because CoverpointBinSingleWildcardModel.get_bin_range() is not implemented, and PyVSC calls it internally when building the cross ignore map.

Minimal Reproducible Example

@vsc.randobj
class Item:
    def __init__(self):
        self.x = vsc.rand_uint8_t()
        self.y = vsc.rand_uint8_t()

@vsc.covergroup
class Cg:
    def __init__(self):
        self.with_sample(dict(it=Item()))
        self.options.name = "cg"

        self.wildcard_cp = vsc.coverpoint(
            self.it.x,
            bins={
                "low":  vsc.wildcard_bin("0b0???????"),
                "high": vsc.wildcard_bin("0b1???????")
            }
        )

        self.plain_cp = vsc.coverpoint(
            self.it.y,
            bins={
                "a": vsc.bin([0, 127]),
                "b": vsc.bin([128, 255])
            }
        )

        # cross containing a coverpoint with wildcard_bins
        self.cross = vsc.cross([self.wildcard_cp, self.plain_cp])

try:
    cg = Cg()
    print("OK")
except Exception as e:
    print(f"FAILED: {type(e).__name__}: {e}")

Expected behavior

The cross is constructed successfully. Wildcard bin ranges are expanded and used for cross bin mapping.

Actual output

FAILED: NotImplementedError: 

Root Cause

CoverpointBinSingleWildcardModel inherits get_bin_range() from CoverpointBinModelBase which raises NotImplementedError. During cross finalization, _build_ignore_map() calls get_bin_range() on every bin of every coverpoint in the cross - including wildcard bins - causing the crash.

Suggested Fix

Implement get_bin_range() in CoverpointBinSingleWildcardModel by expanding the (value, mask) pairs in wildcard_binspec.specs using WildcardBinFactory.valmask2binlist().</issue_description>

<agent_instructions>Add a testcase covering this situation. Investigate and implement a fix</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes NotImplementedError when defining a cross that contains a coverpoint with wildcard bins #270

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