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Negative coverage: prove_wc / const has ty / premise prove_const_has_type(decls, env, assumptions, constant) => (ty_constant, c)

Premise at line 167. Observed failure causes: failed_judgment.

const has ty
LineCoverageSource
1671(prove_const_has_type(decls, env, assumptions, constant) => (ty_constant, c))
1681(prove_after(decls, c, assumptions, Relation::equals(ty_constant, ty)) => c)
──────── ("const has ty")
1703(prove_wc(decls, env, assumptions, Predicate::ConstHasType(constant, ty)) => c)

1 test failed proving this premise:


Source location: tests/consts.rs:68

#[test]
fn generic_mismatch() {
    FormalityTest::new(crates![crate Foo {
                trait Foo<const C> where type_of_const C is bool {}

                // Here, the impl is assuming C is u32, which mismatches the trait bound.
                impl<const C> Foo<C> for u32 where type_of_const C is u32 {}
            }]).err(expect_test::expect![[r#"
                crates/formality-rust/src/prove/prove/prove/prove_via.rs:9:1: no applicable rules for prove_via { goal: Foo(u32, !const_0), via: @ ConstHasType(!const_0 , u32), assumptions: {@ ConstHasType(!const_0 , u32)}, env: Env { variables: [!const_0], bias: Soundness, pending: [], allow_pending_outlives: false } }

                crates/formality-rust/src/prove/prove/prove/prove_via.rs:9:1: no applicable rules for prove_via { goal: u32 = bool, via: @ ConstHasType(!const_0 , u32), assumptions: {@ ConstHasType(!const_0 , u32)}, env: Env { variables: [!const_0], bias: Soundness, pending: [], allow_pending_outlives: false } }

                crates/formality-rust/src/prove/prove/prove/prove_normalize.rs:55:1: no applicable rules for prove_normalize_via { goal: u32, via: @ ConstHasType(!const_0 , u32), assumptions: {@ ConstHasType(!const_0 , u32)}, env: Env { variables: [!const_0], bias: Soundness, pending: [], allow_pending_outlives: false } }

                crates/formality-rust/src/prove/prove/prove/prove_normalize.rs:55:1: no applicable rules for prove_normalize_via { goal: bool, via: @ ConstHasType(!const_0 , u32), assumptions: {@ ConstHasType(!const_0 , u32)}, env: Env { variables: [!const_0], bias: Soundness, pending: [], allow_pending_outlives: false } }

                crates/formality-rust/src/prove/prove/prove/prove_const_has_type.rs:11:1: no applicable rules for prove_const_has_type { constant: !const_0, assumptions: {@ ConstHasType(!const_0 , u32)}, env: Env { variables: [!const_0], bias: Soundness, pending: [], allow_pending_outlives: false }, decls: program([crate core { trait Copy <ty> { } impl Copy for () { } impl Copy for u8 { } impl Copy for u16 { } impl Copy for u32 { } impl Copy for u64 { } impl Copy for i8 { } impl Copy for i16 { } impl Copy for i32 { } impl Copy for i64 { } impl Copy for bool { } impl Copy for usize { } impl Copy for isize { } impl <lt, ty> Copy for &^lt0_0 ^ty0_1 { } trait Drop <ty> { } trait Derefable <ty> { type Target : [] ; } impl <lt, ty> Derefable for &^lt0_0 ^ty0_1 where ^ty0_1 : ^lt0_0 { type Target = ^ty1_1 ; } impl <lt, ty> Derefable for &mut ^lt0_0 ^ty0_1 where ^ty0_1 : ^lt0_0 { type Target = ^ty1_1 ; } }, crate Foo { trait Foo <ty, const> where type_of_const ^const0_1 is bool { } impl <const> Foo <^const0_0> for u32 where type_of_const ^const0_0 is u32 { } }], 222) }

                the rule "trait implied bound" at (prove_wc.rs) failed because
                  expression evaluated to an empty collection: `decls.trait_invariants()`"#]])
}
Failed proof tree