Negative coverage: `borrow_check_fn_ref` / `fn-ref` / premise `let Fn { binder, .. } = env.crates().fn_named(id)?`

Premise at line 629. Observed failure causes: inapplicable.

fn-ref

Line	Coverage	Source
629	1	(let Fn { binder, .. } = env.crates().fn_named(id)?)
630	2	(if binder.len() == args.len())
631	✗	(let FnBoundData { where_clauses, .. } = binder.instantiate_with(args)?)
632	5	(prove_where_clauses(env, assumptions, state, where_clauses) => state)
633	N/A	(let ty = Ty::rigid(RigidName::fn_def(id), args))
		──────── ("fn-ref")
635	43	(borrow_check_fn_ref(env, assumptions, state, id, args) => (ty, state))

1 test failed proving this premise:

Source location: tests/mir_typeck.rs:345 (all coverage from this test)

fn bar() -> u32 {
    let v1: u32 = foo(0_u32);
    return v1;
}

Failed proof tree

check_all_crates failed mod.rs:42
- args
- rule "check all prefixes" mod.rs:54
  - check_crate failed mod.rs:61
    
    args
    
    rule "check crate" mod.rs:74
    
    check_crate_item failed mod.rs:179
    
    rule "free fn" mod.rs:207
    
    check_free_fn failed fns.rs:14
    
    args
    
    rule "check free fn" fns.rs:24
    
    check_fn failed fns.rs:31
    
    args
    
    rule "check fn" fns.rs:54
    
    check_fn_body failed fns.rs:61
    
    args
    
    rule "expr fn body" fns.rs:89
    
    borrow_check failed nll.rs:124
    
    args
    
    rule "borrow_check" nll.rs:135
    
    borrow_check_block failed nll.rs:142
    
    rule "basic block" nll.rs:157
    
    borrow_check_statement failed nll.rs:174
    
    args
    
    rule "let" nll.rs:189
    
    borrow_check_expr_has_ty failed nll.rs:350
    
    args
    
    rule "block" nll.rs:363
    
    borrow_check_expr failed nll.rs:371
    
    args
    
    rule "call" nll.rs:455
    
    borrow_check_expr failed nll.rs:371
    
    args
    
    rule "fn-name" nll.rs:559
    
    borrow_check_fn_ref failed nll.rs:616
    
    args
    
    rule "fn-ref" nll.rs:629 (failed: inapplicable)

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