[hvitved]

Rust still used its bespoke completion-tree and CFG-splitting implementation, which duplicated infrastructure now shared by other language frontends. This migrates Rust to the common codeql.controlflow.ControlFlowGraph framework so it can share the same CFG construction, consistency checks, and maintenance path.

Approach

• Build the Rust CFG through the shared Make0/Make1/Make2 pipeline while preserving Rust-specific semantics for patterns, match, let-else, loops, value-carrying break, and ?.
• Remove the legacy completion and splitting implementation and adapt the public CFG, basic-block, printing, and diagnostics APIs.
• Update SSA and data-flow consumers to use the shared CFG's unique injects(...) relation for semantic AST associations.
• Rework unreachable-code reporting for the shared CFG's reachable-only node model, including correct handling of returning macros and compile-time const/static declarations.

The generated CFG and basic-block baselines change substantially because the shared framework exposes canonical before, in, after, and conditional-after nodes.