[Bug]: PowerShell method calls ($this.M(), [Type]::M()) are dropped from the call graph #3992

Summary

PowerShell method calls are never recorded as call edges. A call like $this.Square(3) from one class method to another — or the static [Calc]::Make() form — is silently dropped from the call graph. Only bare command/function invocations (Helper) are captured.

Version / commit

v8 @ ef4450d (v0.9.73)

Environment

macOS (darwin 24.6), Python 3.13, tree-sitter-powershell via default uv sync.

Minimal reproduction

# calc.ps1
class Calc {
    [int] Square([int]$x) { return $x * $x }
    [int] Run() { return $this.Square(3) }
}

from graphify.extract import extract_powershell
r = extract_powershell("calc.ps1")
calls = [(e["source"], e["target"]) for e in r["edges"] if e["relation"] == "calls"]

Expected

A calls edge .Run() → .Square().

Actual

No calls edge. Both methods are present as nodes, but every method invocation is dropped.

Root cause

The call walker in graphify/extractors/powershell.py only handles command nodes. A method call parses as an invokation_expression (callee in the member_name child, args in argument_list), which was never visited. A bare property read ($this.Name) is a separate member_access node and correctly produces no call.

Scope

A clean checkout reproduces. Member calls should resolve only to methods (not to a free function sharing the name), to avoid false edges on unknown receivers.