The shared CFG library instantiation for Go compiles cleanly. Let me show you the current state of the file:

Read ControlFlowGraphShared.qll, lines 1 to 50

The file compiles successfully. Here's a summary of what was implemented:

ControlFlowGraphShared.qll — Shared CFG library instantiation for Go, wrapped in the GoCfg module to coexist with the existing CFG during transition. Key design decisions:

Ast module (implements AstSig):

Callable = FuncDef with a body
IfStmt — only For if-statements without init (those with init use custom steps)
LoopStmt — uses characteristic predicate pattern (not direct extension) to avoid return type conflicts with BlockStmt
Empty classes for: WhileStmt, DoStmt, ForStmt, ForeachStmt, ThrowStmt, TryStmt, CatchClause, Switch, Case, ConditionalExpr, NullCoalescingExpr (Go doesn't have these constructs)
LogicalAndExpr = LandExpr, LogicalOrExpr = LorExpr, LogicalNotExpr = NotExpr
BooleanLiteral maps to true/false identifiers
skipCfg filters out type expressions, non-rvalue references, parenthesized expressions, etc.
Input module (implements InputSig1 + InputSig2):

Labels: Go statement labels + fallthrough
Custom steps for: if-with-init, for loops, range loops, expression/type switch, case clauses, select statements, defer, go statements
Abrupt completions: panic via calls/div/deref/type-assert/index/conversion, fallthrough, goto
End abrupt completions: labeled statements catch breaks, goto targets
Remaining work (todos 4-6): The GoCfg module is self-contained and doesn't yet replace the existing CFG. Integration with BasicBlocks.qll, IR.qll, and the public ControlFlowGraph.qll API is the next phase — which is a larger effort requiring updates to DataFlow and all downstream consumers.

Author: owen-mc