cairo-lang-lowering 2.21.0

//! > Test that an unused param is trimmed from the signature and the call site.

//! > test_runner_name
test_trim_unused_params

//! > cairo_code
#[target_function]
fn foo(a: felt252, b: u32) {
    callee(0, a, b);
}

fn callee(_assure_specialized: felt252, unused: felt252, used: u32) {
    ext(used);
}

#[allow(extern_outside_corelib)]
extern fn ext(v: u32) nopanic;

//! > semantic_diagnostics

//! > lowering_diagnostics

//! > before
Parameters: v0: core::felt252, v1: core::integer::u32
blk0 (root):
Statements:
  () <- test::callee{0, NotSpecialized, NotSpecialized, }(v0, v1)
End:
  Return()

//! > after
Parameters: v0: core::felt252, v1: core::integer::u32
blk0 (root):
Statements:
  () <- test::callee{0, NotSpecialized, NotSpecialized, }(v1)
End:
  Return()

//! > ==========================================================================

//! > Test that a param only threaded unchanged through the recursive call is trimmed.

//! > test_runner_name
test_trim_unused_params

//! > cairo_code
#[target_function]
fn foo(a: u8, n: felt252) {
    callee(0, a, n);
}

// `threaded` is only passed to the recursive call at its own position, so the entire chain is
// dead.
fn callee(_assure_specialized: felt252, threaded: u8, n: felt252) {
    if n == 0 {
        return;
    }
    callee(0, threaded, n - 1);
}

//! > semantic_diagnostics

//! > lowering_diagnostics

//! > before
Parameters: v0: core::integer::u8, v1: core::felt252
blk0 (root):
Statements:
  () <- test::callee{0, NotSpecialized, NotSpecialized, }(v0, v1)
End:
  Return()

//! > after
Parameters: v0: core::integer::u8, v1: core::felt252
blk0 (root):
Statements:
  () <- test::callee{0, NotSpecialized, NotSpecialized, }(v1)
End:
  Return()

//! > ==========================================================================

//! > Test that an undroppable param threaded through the recursive call is not trimmed.

//! > test_runner_name
test_trim_unused_params

//! > cairo_code
#[target_function]
fn foo(d: Felt252Dict<felt252>) {
    callee(0, d);
}

// `threaded` is only passed to the recursive call at its own position, but as it is undroppable,
// trimming it would leave the dict unconsumed in `foo`.
fn callee(_assure_specialized: felt252, threaded: Felt252Dict<felt252>) {
    callee(0, threaded);
}

//! > semantic_diagnostics

//! > lowering_diagnostics

//! > before
Parameters: v0: core::dict::Felt252Dict::<core::felt252>
blk0 (root):
Statements:
  () <- test::callee{0, NotSpecialized, }(v0)
End:
  Return()

//! > after
Parameters: v0: core::dict::Felt252Dict::<core::felt252>
blk0 (root):
Statements:
  () <- test::callee{0, NotSpecialized, }(v0)
End:
  Return()

//! > ==========================================================================

//! > Test that a used param is not trimmed.

//! > test_runner_name
test_trim_unused_params

//! > cairo_code
#[target_function]
fn foo(a: felt252, b: u32) {
    callee(0, a, b);
}

fn callee(_assure_specialized: felt252, used_a: felt252, used_b: u32) {
    ext((used_a, used_b));
}

#[allow(extern_outside_corelib)]
extern fn ext<T>(t: T) nopanic;

//! > semantic_diagnostics

//! > lowering_diagnostics

//! > before
Parameters: v0: core::felt252, v1: core::integer::u32
blk0 (root):
Statements:
  () <- test::callee{0, NotSpecialized, NotSpecialized, }(v0, v1)
End:
  Return()

//! > after
Parameters: v0: core::felt252, v1: core::integer::u32
blk0 (root):
Statements:
  () <- test::callee{0, NotSpecialized, NotSpecialized, }(v0, v1)
End:
  Return()

//! > ==========================================================================

//! > Test that a conditionally used param is not trimmed.

//! > test_runner_name
test_trim_unused_params

//! > cairo_code
#[target_function]
fn foo(a: u32) {
    callee(0, a);
}

fn callee(_assure_specialized: felt252, conditionally_used: u32) {
    if cond() {
        ext(conditionally_used);
    }
}

#[allow(extern_outside_corelib)]
extern fn ext(v: u32) nopanic;
#[allow(extern_outside_corelib)]
extern fn cond() -> bool nopanic;

//! > semantic_diagnostics

//! > lowering_diagnostics

//! > before
Parameters: v0: core::integer::u32
blk0 (root):
Statements:
  () <- test::callee{0, NotSpecialized, }(v0)
End:
  Return()

//! > after
Parameters: v0: core::integer::u32
blk0 (root):
Statements:
  () <- test::callee{0, NotSpecialized, }(v0)
End:
  Return()

//! > ==========================================================================

//! > Test that a param requiring destruction is not trimmed.

//! > test_runner_name
test_trim_unused_params

//! > cairo_code
#[target_function]
fn foo(b: u32) {
    callee(0, Default::default(), b);
}

fn callee(_assure_specialized: felt252, destructed: Felt252Dict<felt252>, used: u32) {
    ext(used);
}

#[allow(extern_outside_corelib)]
extern fn ext(v: u32) nopanic;

//! > semantic_diagnostics

//! > lowering_diagnostics

//! > before
Parameters: v0: core::integer::u32
blk0 (root):
Statements:
  (v1: core::dict::Felt252Dict::<core::felt252>) <- core::dict::felt252_dict_new::<core::felt252>()
  () <- test::callee{0, NotSpecialized, NotSpecialized, }(v1, v0)
End:
  Return()

//! > after
Parameters: v0: core::integer::u32
blk0 (root):
Statements:
  (v1: core::dict::Felt252Dict::<core::felt252>) <- core::dict::felt252_dict_new::<core::felt252>()
  () <- test::callee{0, NotSpecialized, NotSpecialized, }(v1, v0)
End:
  Return()

//! > ==========================================================================

//! > Test that a param returned on an early exit is not trimmed.

//! > test_runner_name
test_trim_unused_params

//! > cairo_code
#[target_function]
fn foo(a: felt252, b: u32) -> felt252 {
    callee(0, a, b)
}

fn callee(_assure_specialized: felt252, returned: felt252, used: u32) -> felt252 {
    if cond() {
        return returned;
    }
    ext(used);
    0
}

#[allow(extern_outside_corelib)]
extern fn ext(v: u32) nopanic;
#[allow(extern_outside_corelib)]
extern fn cond() -> bool nopanic;

//! > semantic_diagnostics

//! > lowering_diagnostics

//! > before
Parameters: v0: core::felt252, v1: core::integer::u32
blk0 (root):
Statements:
  (v2: core::felt252) <- test::callee{0, NotSpecialized, NotSpecialized, }(v0, v1)
End:
  Return(v2)

//! > after
Parameters: v0: core::felt252, v1: core::integer::u32
blk0 (root):
Statements:
  (v2: core::felt252) <- test::callee{0, NotSpecialized, NotSpecialized, }(v0, v1)
End:
  Return(v2)

//! > ==========================================================================

//! > Test that a param whose only use is a destructure with dead bindings is trimmed (droppable).

//! > test_runner_name
test_trim_unused_params

//! > cairo_code
#[target_function]
fn foo(s: S, b: u32) {
    callee(0, s, b);
}

fn callee(_assure_specialized: felt252, destructured: S, used: u32) {
    let S { a: _x } = destructured;
    ext(used);
}

#[derive(Copy, Drop)]
struct S {
    a: felt252,
}

#[allow(extern_outside_corelib)]
extern fn ext(v: u32) nopanic;

//! > semantic_diagnostics

//! > lowering_diagnostics

//! > before
Parameters: v0: test::S, v1: core::integer::u32
blk0 (root):
Statements:
  () <- test::callee{0, NotSpecialized, NotSpecialized, }(v0, v1)
End:
  Return()

//! > after
Parameters: v0: test::S, v1: core::integer::u32
blk0 (root):
Statements:
  () <- test::callee{0, NotSpecialized, NotSpecialized, }(v1)
End:
  Return()

//! > ==========================================================================

//! > Test that a param threaded between sibling specializations is not trimmed.

//! > test_runner_name
test_trim_unused_params

//! > cairo_code
#[target_function]
fn foo(x: u8, n: felt252) {
    callee(5, x, n);
}

// `threaded` is only passed onwards, but to a *different* specialization of the function, so
// neither sibling may trim it.
fn callee(tag: felt252, threaded: u8, n: felt252) {
    if n == 0 {
        return;
    }
    if tag == 5 {
        callee(6, threaded, n - 1);
    } else {
        callee(5, threaded, n - 1);
    }
}

//! > semantic_diagnostics

//! > lowering_diagnostics

//! > before
Parameters: v0: core::integer::u8, v1: core::felt252
blk0 (root):
Statements:
  () <- test::callee{5, NotSpecialized, NotSpecialized, }(v0, v1)
End:
  Return()

//! > after
Parameters: v0: core::integer::u8, v1: core::felt252
blk0 (root):
Statements:
  () <- test::callee{5, NotSpecialized, NotSpecialized, }(v0, v1)
End:
  Return()

//! > ==========================================================================

//! > Test specialization turning partially specialized struct fields unused.

//! > test_runner_name
test_trim_unused_params

//! > cairo_code
#[target_function]
fn foo(x: felt252, y: u32) {
    callee(false, S6 { a: 1, b: x, c: 3, d: y, e: x, f: 6 })
}

// Specializing on `keep == false` makes the struct params dead, so all of them are trimmed.
fn callee(keep: bool, s: S6) {
    if keep {
        ext(s);
    }
}

#[derive(Drop)]
struct S6 {
    a: felt252,
    b: felt252,
    c: felt252,
    d: u32,
    e: felt252,
    f: felt252,
}

#[allow(extern_outside_corelib)]
extern fn ext(s: S6) nopanic;

//! > semantic_diagnostics

//! > lowering_diagnostics

//! > before
Parameters: v0: core::felt252, v1: core::integer::u32
blk0 (root):
Statements:
  () <- test::callee{bool::False({}), { 1, NotSpecialized, 3, NotSpecialized, NotSpecialized, 6 }, }(v0, v1, v0)
End:
  Return()

//! > after
Parameters: v0: core::felt252, v1: core::integer::u32
blk0 (root):
Statements:
  () <- test::callee{bool::False({}), { 1, NotSpecialized, 3, NotSpecialized, NotSpecialized, 6 }, }()
End:
  Return()

//! > ==========================================================================

//! > Test that a user-visible function is not trimmed, even when a param is unused.

//! > test_runner_name
test_trim_unused_params

//! > cairo_code
#[target_function]
fn foo(a: felt252, b: u32) {
    callee(a, b);
}

// Without a const argument the call is not specialized, and the user-visible `callee` must keep
// its externally callable signature.
fn callee(unused: felt252, used: u32) {
    ext(used);
}

#[allow(extern_outside_corelib)]
extern fn ext(v: u32) nopanic;

//! > semantic_diagnostics

//! > lowering_diagnostics

//! > before
Parameters: v0: core::felt252, v1: core::integer::u32
blk0 (root):
Statements:
  () <- test::callee(v0, v1)
End:
  Return()

//! > after
Parameters: v0: core::felt252, v1: core::integer::u32
blk0 (root):
Statements:
  () <- test::callee(v0, v1)
End:
  Return()