diff --git a/src/bin/pattern_typecheck.rs b/src/bin/pattern_typecheck.rs
new file mode 100644
index 0000000..03649f5
--- /dev/null
+++ b/src/bin/pattern_typecheck.rs
@@ -0,0 +1,185 @@
+//! pattern_typecheck — times the type checker on the internal-bench cases
+//! reduced to the FPPC path-pattern surface (MATCH/RETURN dropped, a
+//! query-level WHERE inlined into the descriptor). Isolated from the runtime,
+//! with a reused checker and WARMUP + ITERS iterations.
+//!
+//!   cargo run --release --bin pattern_typecheck -- [path.gdb] [out.csv]
+//!
+//! Emits per-case check medians to `results_rust_typecheck.csv` and asserts each
+//! verdict (valid / empty / invalid) matches the expected classification. It
+//! measures only Rust: any comparison against another checker is a separate step
+//! that joins this CSV with the other's — this bench does not read either.
+
+use std::fs::File;
+use std::hint::black_box;
+use std::io::Write;
+use std::path::Path;
+use std::time::Instant;
+
+use frogql::store::lazy::LazyGraphStore;
+use frogql::typing::checker::Typechecker;
+
+const WARMUP: usize = 1000;
+const ITERS: usize = 10000;
+const DEFAULT_GDB: &str = "bench/data/ldbc-sf0.1.gdb";
+
+fn median_min_ns(mut v: Vec<u128>) -> (u128, u128) {
+    v.sort_unstable();
+    (v[v.len() / 2], v[0])
+}
+
+fn main() {
+    let mut args = std::env::args().skip(1);
+    let gdb = args.next().unwrap_or_else(|| DEFAULT_GDB.to_string());
+    let out = args
+        .next()
+        .unwrap_or_else(|| "results_rust_typecheck.csv".to_string());
+
+    let lazy = LazyGraphStore::open(Path::new(&gdb)).unwrap_or_else(|e| panic!("open {gdb}: {e}"));
+    let schema = lazy.catalog().active_schema();
+
+    // Reduced path-pattern queries, one per internal-bench case (undirected `~`
+    // edges, query-level WHERE inlined; the IC and aggregate cases are dropped
+    // because they are not path patterns). i_parse is omitted (a parse error has
+    // no typecheck to time).
+    let cases: &[(&str, &str, &str)] = &[
+        ("v_label", "valid", "(p: Person)"),
+        ("v_chain_knows", "valid", "(p: Person)~[:knows]~(f: Person)"),
+        ("v_where", "valid", "(p: Person WHERE p.id = 933)"),
+        (
+            "v_empty_by_data",
+            "valid",
+            "(p: Person WHERE p.id = 1234567890)",
+        ),
+        (
+            "e_chain4_bad_leaf",
+            "empty",
+            "(a: Person)~[:knows]~(b: Person)~[:knows]~(c: Person)~[:knows]~(d: Wagumi)",
+        ),
+        (
+            "e_chain_mid_bad",
+            "empty",
+            "(a: Person)~[:knows]~(b: Wagumi)~[:knows]~(c: Person)",
+        ),
+        (
+            "e_bad_edge_deep",
+            "empty",
+            "(a: Person)~[:knows]~(b: Person)-[:noSuchEdge]->(c: Person)",
+        ),
+        (
+            "e_ic2_bad_msg",
+            "empty",
+            "(p: Person)~[:knows]~(friend: Person)<-[:hasCreator]-(m: Wagumi)",
+        ),
+        (
+            "e_conflict_label_deep",
+            "empty",
+            "(a: Person)~[:knows]~(b: Person)-[:hasCreator]->(b: Comment)",
+        ),
+        (
+            "e_type_mismatch_chain",
+            "empty",
+            "(a: Person)~[:knows]~(b: Person)~[:knows]~(c: Person WHERE c.firstName = 933)",
+        ),
+        (
+            "e_union_all_bad",
+            "empty",
+            "(x: Wagumi)<-[:hasCreator]-(c: Comment) | (x: Wagumi)<-[:hasCreator]-(c: Post)",
+        ),
+        (
+            "e_repeat_bad_leaf",
+            "empty",
+            "(p: Person)~[:knows]~{1,2}(f: Wagumi)",
+        ),
+        ("e_label_only", "empty", "(x: Wagumi)"),
+        (
+            "e_type_clash_arith",
+            "empty",
+            "(p: Person WHERE p.firstName + p.id > 0)",
+        ),
+        (
+            "i_unbound_compound_where",
+            "invalid",
+            "(p: Person WHERE p.id = 933 AND q.id = 1)",
+        ),
+        (
+            "i_unbound_in_where_chain",
+            "invalid",
+            "(a: Person)~[:knows]~(b: Person)~[:knows]~(c: Person WHERE q.id = 1)",
+        ),
+    ];
+
+    println!(
+        "\n{:<26}{:>7}{:>9}{:>15}",
+        "case", "exp", "got", "check_med_us"
+    );
+    println!("{}", "-".repeat(57));
+    let mut rows: Vec<(String, String, String, u128, u128, bool)> = Vec::new();
+    let mut mismatches = 0usize;
+    for (id, expected, q) in cases {
+        let parsed = frogql::parser::parse_query(q).expect("parse");
+        let elaborated = frogql::elaborate::elaborate_query(parsed);
+        let mut tc = Typechecker::new(schema.clone());
+        let r = tc.check_query(&elaborated);
+        let got = if !r.ok {
+            "invalid"
+        } else if r.empty {
+            "empty"
+        } else {
+            "valid"
+        };
+        for _ in 0..WARMUP {
+            black_box(tc.check_query(black_box(&elaborated)));
+        }
+        let mut samples = Vec::with_capacity(ITERS);
+        for _ in 0..ITERS {
+            let t = Instant::now();
+            black_box(tc.check_query(black_box(&elaborated)));
+            samples.push(t.elapsed().as_nanos());
+        }
+        let (med, min) = median_min_ns(samples);
+        let ok = got == *expected;
+        if !ok {
+            mismatches += 1;
+        }
+        println!(
+            "{:<26}{:>7}{:>9}{:>15.3}{}",
+            id,
+            expected,
+            got,
+            med as f64 / 1000.0,
+            if ok { "" } else { "  <-- VERDICT MISMATCH" }
+        );
+        rows.push((
+            id.to_string(),
+            expected.to_string(),
+            got.to_string(),
+            med,
+            min,
+            ok,
+        ));
+    }
+    println!("{}", "-".repeat(57));
+
+    let mut f = File::create(&out).unwrap_or_else(|e| panic!("create {out}: {e}"));
+    writeln!(f, "case,expected,got,check_med_ns,check_min_ns,status").unwrap();
+    for (id, exp, got, med, min, ok) in &rows {
+        writeln!(
+            f,
+            "{id},{exp},{got},{med},{min},{}",
+            if *ok { "PASS" } else { "FAIL" }
+        )
+        .unwrap();
+    }
+    println!("wrote {out}");
+    if mismatches == 0 {
+        println!(
+            "SANITY OK: rust matched the expected verdict on all {} cases.",
+            rows.len()
+        );
+    } else {
+        println!(
+            "WARNING: {mismatches} verdict mismatch(es) -- investigate before trusting timings."
+        );
+    }
+}