e3cd43eb00
Currently, the def span of a funtion encompasses the entire function
signature and body. However, this is usually unnecessarily verbose - when we are
pointing at an entire function in a diagnostic, we almost always want to
point at the signature. The actual contents of the body tends to be
irrelevant to the diagnostic we are emitting, and just takes up
additional screen space.
This commit changes the `def_span` of all function items (freestanding
functions, `impl`-block methods, and `trait`-block methods) to be the
span of the signature. For example, the function
```rust
pub fn foo<T>(val: T) -> T { val }
```
now has a `def_span` corresponding to `pub fn foo<T>(val: T) -> T`
(everything before the opening curly brace).
Trait methods without a body have a `def_span` which includes the
trailing semicolon. For example:
```rust
trait Foo {
fn bar();
}```
the function definition `Foo::bar` has a `def_span` of `fn bar();`
This makes our diagnostic output much shorter, and emphasizes
information that is relevant to whatever diagnostic we are reporting.
We continue to use the full span (including the body) in a few of
places:
* MIR building uses the full span when building source scopes.
* 'Outlives suggestions' use the full span to sort the diagnostics being
emitted.
* The `#[rustc_on_unimplemented(enclosing_scope="in this scope")]`
attribute points the entire scope body.
* The 'unconditional recursion' lint uses the full span to show
additional context for the recursive call.
All of these cases work only with local items, so we don't need to
add anything extra to crate metadata.
103 lines
4.4 KiB
Plaintext
103 lines
4.4 KiB
Plaintext
error[E0308]: mismatched types
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--> $DIR/issue-20831-debruijn.rs:28:5
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LL | / fn subscribe(&mut self, t : Box<dyn Subscriber<Input=<Self as Publisher>::Output> + 'a>) {
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LL | | // Not obvious, but there is an implicit lifetime here -------^
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LL | |
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LL | |
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... |
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LL | | self.sub = t;
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LL | | }
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| |_____^ lifetime mismatch
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= note: expected type `'a`
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found type `'_`
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note: the anonymous lifetime #2 defined on the method body at 28:5...
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--> $DIR/issue-20831-debruijn.rs:28:5
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LL | fn subscribe(&mut self, t : Box<dyn Subscriber<Input=<Self as Publisher>::Output> + 'a>) {
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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note: ...does not necessarily outlive the lifetime `'a` as defined on the impl at 26:6
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--> $DIR/issue-20831-debruijn.rs:26:6
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LL | impl<'a> Publisher<'a> for MyStruct<'a> {
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| ^^
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error[E0308]: mismatched types
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--> $DIR/issue-20831-debruijn.rs:28:5
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LL | / fn subscribe(&mut self, t : Box<dyn Subscriber<Input=<Self as Publisher>::Output> + 'a>) {
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LL | | // Not obvious, but there is an implicit lifetime here -------^
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LL | |
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LL | |
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... |
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LL | | self.sub = t;
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LL | | }
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| |_____^ lifetime mismatch
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= note: expected type `'a`
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found type `'_`
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note: the lifetime `'a` as defined on the impl at 26:6...
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--> $DIR/issue-20831-debruijn.rs:26:6
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LL | impl<'a> Publisher<'a> for MyStruct<'a> {
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| ^^
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note: ...does not necessarily outlive the anonymous lifetime #2 defined on the method body at 28:5
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--> $DIR/issue-20831-debruijn.rs:28:5
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LL | fn subscribe(&mut self, t : Box<dyn Subscriber<Input=<Self as Publisher>::Output> + 'a>) {
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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error[E0495]: cannot infer an appropriate lifetime for lifetime parameter `'a` due to conflicting requirements
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--> $DIR/issue-20831-debruijn.rs:28:33
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LL | fn subscribe(&mut self, t : Box<dyn Subscriber<Input=<Self as Publisher>::Output> + 'a>) {
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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note: first, the lifetime cannot outlive the anonymous lifetime #2 defined on the method body at 28:5...
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--> $DIR/issue-20831-debruijn.rs:28:5
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LL | fn subscribe(&mut self, t : Box<dyn Subscriber<Input=<Self as Publisher>::Output> + 'a>) {
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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note: ...but the lifetime must also be valid for the lifetime `'a` as defined on the impl at 26:6...
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--> $DIR/issue-20831-debruijn.rs:26:6
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LL | impl<'a> Publisher<'a> for MyStruct<'a> {
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| ^^
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note: ...so that the types are compatible
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--> $DIR/issue-20831-debruijn.rs:28:33
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LL | fn subscribe(&mut self, t : Box<dyn Subscriber<Input=<Self as Publisher>::Output> + 'a>) {
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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= note: expected `Publisher<'_>`
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found `Publisher<'_>`
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error[E0495]: cannot infer an appropriate lifetime for lifetime parameter `'a` due to conflicting requirements
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--> $DIR/issue-20831-debruijn.rs:28:33
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LL | fn subscribe(&mut self, t : Box<dyn Subscriber<Input=<Self as Publisher>::Output> + 'a>) {
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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note: first, the lifetime cannot outlive the anonymous lifetime #2 defined on the method body at 28:5...
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--> $DIR/issue-20831-debruijn.rs:28:5
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LL | fn subscribe(&mut self, t : Box<dyn Subscriber<Input=<Self as Publisher>::Output> + 'a>) {
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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note: ...but the lifetime must also be valid for the lifetime `'a` as defined on the impl at 26:6...
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--> $DIR/issue-20831-debruijn.rs:26:6
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LL | impl<'a> Publisher<'a> for MyStruct<'a> {
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| ^^
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note: ...so that the types are compatible
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--> $DIR/issue-20831-debruijn.rs:28:33
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LL | fn subscribe(&mut self, t : Box<dyn Subscriber<Input=<Self as Publisher>::Output> + 'a>) {
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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= note: expected `Publisher<'_>`
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found `Publisher<'_>`
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error: aborting due to 4 previous errors
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Some errors have detailed explanations: E0308, E0495.
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For more information about an error, try `rustc --explain E0308`.
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