As shown in the code, I have not applied any explicit constraints to the generic parameter T. However, the parameter's type, MyBuffer<T>, requires the structural bounds T: Default + 'static in its definition.

1. This code is accepted by the compiler (the function signature compiles).
2. But if I add the line T::default() to the function body, the code fails to compile.

My question is:

What is the specific Rust rule that governs this behavior?

If the function's generic parameter T truly has no explicit bounds, why does the compiler accept the function signature where T appears to violate the structural constraints required by MyBuffer<T>? (i.e., Why is the Well-Formedness Predicate not immediately enforced on the signature?)

Conversely, if the compiler has successfully determined the necessary bounds for T (i.e., T: Default), why does the method call T::default() fail to compile inside the function body? (i.e., Why are the structural bounds not imported into the function body's scope for Trait resolution?)

fn alloc_clone<T>(
    pined: &mut Pin<&'static mut BufList>,
) -> Result<Pin<&'static mut MyBuffer<T>>, bool> {
     [...]
}

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