Facebook Infer Checkers vs fold Detectors — Gap Matrix
Generated 2026-05-29. Maps every Infer C/C++ checker to fold's existing detectors.
Coverage Summary
Infer has ~30 C/C++ checkers across 6 categories. fold covers 9 of these domains.
| Category |
Infer Checkers |
fold Has |
fold Missing |
| Memory safety |
5 |
5 |
0 |
| Resource management |
4 |
3 |
1 |
| Concurrency |
7 |
0 |
7 |
| Performance |
5 |
1 |
4 |
| C++ lifetime |
4 |
0 |
4 |
| Taint / security |
3 |
1 |
2 |
| Total |
~30 |
10 |
18 |
Key Gaps
Concurrency (7 Infer checkers, 0 in fold)
| Infer Checker |
What it finds |
| RacerD |
Data races on Java/ObjC fields (some C++ support) |
| Starvation |
Deadlocks from lock ordering |
| Thread-safety |
Unsafe publication, missing synchronization |
| Lock consistency |
Lock/unlock imbalance |
| GuardedBy |
Missing lock acquisition before accessing guarded field |
fold opportunity: Syntactic lock/unlock imbalance detection (low effort). Full RacerD equivalent requires thread interleaving model (high effort, beyond current scope).
Resource Management (1 gap)
| Infer Checker |
fold Equivalent |
| Resource leak (files) |
memory-leak (heap only) — missing file/socket leak |
| Memory leak |
memory-leak ✅ |
C++ Lifetime (4 Infer checkers, 0 in fold)
| Infer Checker |
What it finds |
fold Feasibility |
| Dangling pointer |
Use-after-free |
use-after-free ✅ (observer-based) |
| Dangling reference |
Reference to temporary |
NEW — syntactic check |
| Ownership |
shared_ptr cycles |
Beyond scope |
| Smart pointer |
unique_ptr/shared_ptr misuse |
NEW — syntactic check |
Performance (5 Infer checkers, 1 in fold)
| Infer Checker |
fold Equivalent |
| Unnecessary copy |
redundant-store (partial) |
| Expensive loop invariant |
NEW — Z3 could prove expression is loop-invariant |
| Vector reallocation |
NEW — detect reserve() opportunities |
| Boxed primitive |
N/A (Java-specific) |
What fold Does Better Than Infer
| Capability |
fold |
Infer |
| Z3-proved findings |
Yes (UNSAT proofs) |
No (biabduction, heuristic) |
| Semantic equivalence |
Yes (Type-4 clones) |
No |
| Binary scanning |
Yes |
No |
| Dead branch detection |
Yes |
Partial (pulse dead store) |
| Cross-language (Rust/Swift) |
Yes |
No |
| Observer architecture |
Yes (pluggable detectors) |
No (checker registration) |
Recommended Additions
| Priority |
Detector |
Approach |
Effort |
| 1 |
File/socket leak |
Extend memory-leak to track non-heap resources |
M |
| 2 |
Dangling reference |
Syntactic: detect references to temporaries |
S |
| 3 |
Lock imbalance |
Syntactic: count lock/unlock per function |
S |
| 4 |
Vector reallocation |
Syntactic: detect push_back in loop without reserve |
S |
| 5 |
Expensive loop invariant |
Z3: prove expression is loop-invariant |
L |
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