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review comments: wording and style

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This commit is contained in:
Esteban Küber 2020-06-23 13:01:24 -07:00
parent f84b7e1b05
commit 6e8aa1ff27
3 changed files with 32 additions and 37 deletions
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29
src/librustc_typeck/check/mod.rs
View File

@ -5502,7 +5502,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
expected: Ty<'tcx>,
found: Ty<'tcx>,
) {
match (&expected.kind, &found.kind) {
let (sig, did, substs) = match (&expected.kind, &found.kind) {
(ty::FnDef(did1, substs1), ty::FnDef(did2, substs2)) => {
let sig1 = self.tcx.fn_sig(*did1).subst(self.tcx, substs1);
let sig2 = self.tcx.fn_sig(*did2).subst(self.tcx, substs2);
@ -5513,29 +5513,24 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
"different `fn` items always have unique types, even if their signatures are \
the same",
);
err.help(&format!("change the expectation to require function pointer `{}`", sig1));
err.help(&format!(
"if the expectation is due to type inference, cast the expected `fn` to a \
function pointer: `{} as {}`",
self.tcx.def_path_str_with_substs(*did1, substs1),
sig1
));
(sig1, *did1, substs1)
}
(ty::FnDef(did, substs), ty::FnPtr(sig2)) => {
let sig1 = self.tcx.fn_sig(*did).subst(self.tcx, substs);
if sig1 != *sig2 {
return;
}
err.help(&format!("change the expectation to require function pointer `{}`", sig1));
err.help(&format!(
"if the expectation is due to type inference, cast the expected `fn` to a \
function pointer: `{} as {}`",
self.tcx.def_path_str_with_substs(*did, substs),
sig1
));
(sig1, *did, substs)
}
_ => {}
}
_ => return,
};
err.help(&format!("change the expected type to be function pointer `{}`", sig));
err.help(&format!(
"if the expected type is due to type inference, cast the expected `fn` to a function \
pointer: `{} as {}`",
self.tcx.def_path_str_with_substs(did, substs),
sig
));
}
/// A common error is to add an extra semicolon:

20
src/test/ui/fn/fn-item-type.rs
View File

@ -16,15 +16,15 @@ fn main() {
//~| found fn item `fn(_) -> _ {bar::<u8>}`
//~| expected fn item, found a different fn item
//~| different `fn` items always have unique types, even if their signatures are the same
//~| change the expectation to require function pointer
//~| if the expectation is due to type inference, cast the expected `fn` to a function pointer
//~| change the expected type to be function pointer
//~| if the expected type is due to type inference, cast the expected `fn` to a function pointer
eq(foo::<u8>, foo::<i8>);
//~^ ERROR mismatched types
//~| expected `u8`, found `i8`
//~| different `fn` items always have unique types, even if their signatures are the same
//~| change the expectation to require function pointer
//~| if the expectation is due to type inference, cast the expected `fn` to a function pointer
//~| change the expected type to be function pointer
//~| if the expected type is due to type inference, cast the expected `fn` to a function pointer
eq(bar::<String>, bar::<Vec<u8>>);
//~^ ERROR mismatched types
@ -32,24 +32,24 @@ fn main() {
//~| found fn item `fn(_) -> _ {bar::<std::vec::Vec<u8>>}`
//~| expected struct `std::string::String`, found struct `std::vec::Vec`
//~| different `fn` items always have unique types, even if their signatures are the same
//~| change the expectation to require function pointer
//~| if the expectation is due to type inference, cast the expected `fn` to a function pointer
//~| change the expected type to be function pointer
//~| if the expected type is due to type inference, cast the expected `fn` to a function pointer
// Make sure we distinguish between trait methods correctly.
eq(<u8 as Foo>::foo, <u16 as Foo>::foo);
//~^ ERROR mismatched types
//~| expected `u8`, found `u16`
//~| different `fn` items always have unique types, even if their signatures are the same
//~| change the expectation to require function pointer
//~| if the expectation is due to type inference, cast the expected `fn` to a function pointer
//~| change the expected type to be function pointer
//~| if the expected type is due to type inference, cast the expected `fn` to a function pointer
eq(foo::<u8>, bar::<u8> as fn(isize) -> isize);
//~^ ERROR mismatched types
//~| expected fn item `fn(_) -> _ {foo::<u8>}`
//~| found fn pointer `fn(_) -> _`
//~| expected fn item, found fn pointer
//~| change the expectation to require function pointer
//~| if the expectation is due to type inference, cast the expected `fn` to a function pointer
//~| change the expected type to be function pointer
//~| if the expected type is due to type inference, cast the expected `fn` to a function pointer
eq(foo::<u8> as fn(isize) -> isize, bar::<u8>); // ok!
}

20
src/test/ui/fn/fn-item-type.stderr
View File

@ -7,8 +7,8 @@ LL | eq(foo::<u8>, bar::<u8>);
= note: expected fn item `fn(_) -> _ {foo::<u8>}`
found fn item `fn(_) -> _ {bar::<u8>}`
= note: different `fn` items always have unique types, even if their signatures are the same
= help: change the expectation to require function pointer `fn(isize) -> isize`
= help: if the expectation is due to type inference, cast the expected `fn` to a function pointer: `foo::<u8> as fn(isize) -> isize`
= help: change the expected type to be function pointer `fn(isize) -> isize`
= help: if the expected type is due to type inference, cast the expected `fn` to a function pointer: `foo::<u8> as fn(isize) -> isize`
error[E0308]: mismatched types
--> $DIR/fn-item-type.rs:22:19
@ -19,8 +19,8 @@ LL | eq(foo::<u8>, foo::<i8>);
= note: expected fn item `fn(_) -> _ {foo::<u8>}`
found fn item `fn(_) -> _ {foo::<i8>}`
= note: different `fn` items always have unique types, even if their signatures are the same
= help: change the expectation to require function pointer `fn(isize) -> isize`
= help: if the expectation is due to type inference, cast the expected `fn` to a function pointer: `foo::<u8> as fn(isize) -> isize`
= help: change the expected type to be function pointer `fn(isize) -> isize`
= help: if the expected type is due to type inference, cast the expected `fn` to a function pointer: `foo::<u8> as fn(isize) -> isize`
error[E0308]: mismatched types
--> $DIR/fn-item-type.rs:29:23
@ -31,8 +31,8 @@ LL | eq(bar::<String>, bar::<Vec<u8>>);
= note: expected fn item `fn(_) -> _ {bar::<std::string::String>}`
found fn item `fn(_) -> _ {bar::<std::vec::Vec<u8>>}`
= note: different `fn` items always have unique types, even if their signatures are the same
= help: change the expectation to require function pointer `fn(isize) -> isize`
= help: if the expectation is due to type inference, cast the expected `fn` to a function pointer: `bar::<std::string::String> as fn(isize) -> isize`
= help: change the expected type to be function pointer `fn(isize) -> isize`
= help: if the expected type is due to type inference, cast the expected `fn` to a function pointer: `bar::<std::string::String> as fn(isize) -> isize`
error[E0308]: mismatched types
--> $DIR/fn-item-type.rs:39:26
@ -43,8 +43,8 @@ LL | eq(<u8 as Foo>::foo, <u16 as Foo>::foo);
= note: expected fn item `fn() {<u8 as Foo>::foo}`
found fn item `fn() {<u16 as Foo>::foo}`
= note: different `fn` items always have unique types, even if their signatures are the same
= help: change the expectation to require function pointer `fn()`
= help: if the expectation is due to type inference, cast the expected `fn` to a function pointer: `<u8 as Foo>::foo as fn()`
= help: change the expected type to be function pointer `fn()`
= help: if the expected type is due to type inference, cast the expected `fn` to a function pointer: `<u8 as Foo>::foo as fn()`
error[E0308]: mismatched types
--> $DIR/fn-item-type.rs:46:19
@ -54,8 +54,8 @@ LL | eq(foo::<u8>, bar::<u8> as fn(isize) -> isize);
|
= note: expected fn item `fn(_) -> _ {foo::<u8>}`
found fn pointer `fn(_) -> _`
= help: change the expectation to require function pointer `fn(isize) -> isize`
= help: if the expectation is due to type inference, cast the expected `fn` to a function pointer: `foo::<u8> as fn(isize) -> isize`
= help: change the expected type to be function pointer `fn(isize) -> isize`
= help: if the expected type is due to type inference, cast the expected `fn` to a function pointer: `foo::<u8> as fn(isize) -> isize`
error: aborting due to 5 previous errors