Error message doesn't give full path in suggestion.

[Lokathor]

https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=d854c189b0a198c091da3ccf429e0ec9

It suggests adding Sum to the bounds, but Sum is not in scope, so typing directly what it says just leads to another error.

Interestingly, Mul was suggested as std::ops::Mul.

So it should likely suggest the correct prefix for the Sum trait.

[Rustin170506]

@rustbot claim

[Rustin170506]

@estebank I've found the corresponding suggest and trait_ref, but I don't know how to get its prefix, do you have any suggestions?

[estebank]

@hi-rustin you'll want to use this function where the suggestion is being created

rust/compiler/rustc_middle/src/ty/print/pretty.rs

Lines 102 to 112 in 72ebebe

	/// Prevent path trimming if it is turned on. Path trimming affects `Display` impl
	/// of various rustc types, for example `std::vec::Vec` would be trimmed to `Vec`,
	/// if no other `Vec` is found.
	pub fn with_no_trimmed_paths<F: FnOnce() -> R, R>(f: F) -> R {
	NO_TRIMMED_PATH.with(|flag| {
	let old = flag.replace(true);
	let result = f();
	flag.set(old);
	result
	})
	}