Auto merge of #137348 - compiler-errors:span-trim, r=estebank

More sophisticated span trimming for suggestions

Previously #136958 only cared about prefixes or suffixes. Now it detects more cases where a suggestion is "sandwiched" by unchanged code on the left or the right. Would be cool if we could detect several insertions, like `ACE` going to `ABCDE`, extracting `B` and `D`, but that seems unwieldy.

r? `@estebank`

Author: bors

tests/ui/async_yields_async.stderr

@@ -14,9 +14,9 @@ LL | |      };
    = help: to override `-D warnings` add `#[allow(clippy::async_yields_async)]`
 help: consider awaiting this value
    |
-LL ~         async {
-LL +             3
-LL +         }.await
+LL |         async {
+LL |             3
+LL ~         }.await
    |
 
 error: an async construct yields a type which is itself awaitable
@@ -46,9 +46,9 @@ LL | |      };
    |
 help: consider awaiting this value
    |
-LL ~         async {
-LL +             3
-LL +         }.await
+LL |         async {
+LL |             3
+LL ~         }.await
    |
 
 error: an async construct yields a type which is itself awaitable

tests/ui/borrow_deref_ref_unfixable.stderr

@@ -13,9 +13,8 @@ LL +         let x: &str = s;
    |
 help: if you would like to deref, try using `&**`
    |
-LL -         let x: &str = &*s;
-LL +         let x: &str = &**s;
-   |
+LL |         let x: &str = &**s;
+   |                         +
 
 error: aborting due to 1 previous error
 

tests/ui/fn_to_numeric_cast_any.stderr

@@ -8,9 +8,8 @@ LL |     let _ = foo as i8;
    = help: to override `-D warnings` add `#[allow(clippy::fn_to_numeric_cast_any)]`
 help: did you mean to invoke the function?
    |
-LL -     let _ = foo as i8;
-LL +     let _ = foo() as i8;
-   |
+LL |     let _ = foo() as i8;
+   |                ++
 
 error: casting function pointer `foo` to `i16`
   --> tests/ui/fn_to_numeric_cast_any.rs:26:13
@@ -20,9 +19,8 @@ LL |     let _ = foo as i16;
    |
 help: did you mean to invoke the function?
    |
-LL -     let _ = foo as i16;
-LL +     let _ = foo() as i16;
-   |
+LL |     let _ = foo() as i16;
+   |                ++
 
 error: casting function pointer `foo` to `i32`
   --> tests/ui/fn_to_numeric_cast_any.rs:28:13
@@ -32,9 +30,8 @@ LL |     let _ = foo as i32;
    |
 help: did you mean to invoke the function?
    |
-LL -     let _ = foo as i32;
-LL +     let _ = foo() as i32;
-   |
+LL |     let _ = foo() as i32;
+   |                ++
 
 error: casting function pointer `foo` to `i64`
   --> tests/ui/fn_to_numeric_cast_any.rs:30:13
@@ -44,9 +41,8 @@ LL |     let _ = foo as i64;
    |
 help: did you mean to invoke the function?
    |
-LL -     let _ = foo as i64;
-LL +     let _ = foo() as i64;
-   |
+LL |     let _ = foo() as i64;
+   |                ++
 
 error: casting function pointer `foo` to `i128`
   --> tests/ui/fn_to_numeric_cast_any.rs:32:13
@@ -56,9 +52,8 @@ LL |     let _ = foo as i128;
    |
 help: did you mean to invoke the function?
    |
-LL -     let _ = foo as i128;
-LL +     let _ = foo() as i128;
-   |
+LL |     let _ = foo() as i128;
+   |                ++
 
 error: casting function pointer `foo` to `isize`
   --> tests/ui/fn_to_numeric_cast_any.rs:34:13
@@ -68,9 +63,8 @@ LL |     let _ = foo as isize;
    |
 help: did you mean to invoke the function?
    |
-LL -     let _ = foo as isize;
-LL +     let _ = foo() as isize;
-   |
+LL |     let _ = foo() as isize;
+   |                ++
 
 error: casting function pointer `foo` to `u8`
   --> tests/ui/fn_to_numeric_cast_any.rs:37:13
@@ -80,9 +74,8 @@ LL |     let _ = foo as u8;
    |
 help: did you mean to invoke the function?
    |
-LL -     let _ = foo as u8;
-LL +     let _ = foo() as u8;
-   |
+LL |     let _ = foo() as u8;
+   |                ++
 
 error: casting function pointer `foo` to `u16`
   --> tests/ui/fn_to_numeric_cast_any.rs:39:13
@@ -92,9 +85,8 @@ LL |     let _ = foo as u16;
    |
 help: did you mean to invoke the function?
    |
-LL -     let _ = foo as u16;
-LL +     let _ = foo() as u16;
-   |
+LL |     let _ = foo() as u16;
+   |                ++
 
 error: casting function pointer `foo` to `u32`
   --> tests/ui/fn_to_numeric_cast_any.rs:41:13
@@ -104,9 +96,8 @@ LL |     let _ = foo as u32;
    |
 help: did you mean to invoke the function?
    |
-LL -     let _ = foo as u32;
-LL +     let _ = foo() as u32;
-   |
+LL |     let _ = foo() as u32;
+   |                ++
 
 error: casting function pointer `foo` to `u64`
   --> tests/ui/fn_to_numeric_cast_any.rs:43:13
@@ -116,9 +107,8 @@ LL |     let _ = foo as u64;
    |
 help: did you mean to invoke the function?
    |
-LL -     let _ = foo as u64;
-LL +     let _ = foo() as u64;
-   |
+LL |     let _ = foo() as u64;
+   |                ++
 
 error: casting function pointer `foo` to `u128`
   --> tests/ui/fn_to_numeric_cast_any.rs:45:13
@@ -128,9 +118,8 @@ LL |     let _ = foo as u128;
    |
 help: did you mean to invoke the function?
    |
-LL -     let _ = foo as u128;
-LL +     let _ = foo() as u128;
-   |
+LL |     let _ = foo() as u128;
+   |                ++
 
 error: casting function pointer `foo` to `usize`
   --> tests/ui/fn_to_numeric_cast_any.rs:47:13
@@ -140,9 +129,8 @@ LL |     let _ = foo as usize;
    |
 help: did you mean to invoke the function?
    |
-LL -     let _ = foo as usize;
-LL +     let _ = foo() as usize;
-   |
+LL |     let _ = foo() as usize;
+   |                ++
 
 error: casting function pointer `Struct::static_method` to `usize`
   --> tests/ui/fn_to_numeric_cast_any.rs:52:13
@@ -152,9 +140,8 @@ LL |     let _ = Struct::static_method as usize;
    |
 help: did you mean to invoke the function?
    |
-LL -     let _ = Struct::static_method as usize;
-LL +     let _ = Struct::static_method() as usize;
-   |
+LL |     let _ = Struct::static_method() as usize;
+   |                                  ++
 
 error: casting function pointer `f` to `usize`
   --> tests/ui/fn_to_numeric_cast_any.rs:57:5
@@ -164,9 +151,8 @@ LL |     f as usize
    |
 help: did you mean to invoke the function?
    |
-LL -     f as usize
-LL +     f() as usize
-   |
+LL |     f() as usize
+   |      ++
 
 error: casting function pointer `T::static_method` to `usize`
   --> tests/ui/fn_to_numeric_cast_any.rs:62:5
@@ -176,9 +162,8 @@ LL |     T::static_method as usize
    |
 help: did you mean to invoke the function?
    |
-LL -     T::static_method as usize
-LL +     T::static_method() as usize
-   |
+LL |     T::static_method() as usize
+   |                     ++
 
 error: casting function pointer `(clos as fn(u32) -> u32)` to `usize`
   --> tests/ui/fn_to_numeric_cast_any.rs:69:13
@@ -188,9 +173,8 @@ LL |     let _ = (clos as fn(u32) -> u32) as usize;
    |
 help: did you mean to invoke the function?
    |
-LL -     let _ = (clos as fn(u32) -> u32) as usize;
-LL +     let _ = (clos as fn(u32) -> u32)() as usize;
-   |
+LL |     let _ = (clos as fn(u32) -> u32)() as usize;
+   |                                     ++
 
 error: casting function pointer `foo` to `*const ()`
   --> tests/ui/fn_to_numeric_cast_any.rs:74:13
@@ -200,9 +184,8 @@ LL |     let _ = foo as *const ();
    |
 help: did you mean to invoke the function?
    |
-LL -     let _ = foo as *const ();
-LL +     let _ = foo() as *const ();
-   |
+LL |     let _ = foo() as *const ();
+   |                ++
 
 error: aborting due to 17 previous errors
 

tests/ui/implicit_hasher.stderr

@@ -78,9 +78,8 @@ LL | pub fn map(map: &mut HashMap<i32, i32>) {}
    |
 help: add a type parameter for `BuildHasher`
    |
-LL - pub fn map(map: &mut HashMap<i32, i32>) {}
-LL + pub fn map<S: ::std::hash::BuildHasher>(map: &mut HashMap<i32, i32, S>) {}
-   |
+LL | pub fn map<S: ::std::hash::BuildHasher>(map: &mut HashMap<i32, i32, S>) {}
+   |           +++++++++++++++++++++++++++++                           +++
 
 error: parameter of type `HashSet` should be generalized over different hashers
   --> tests/ui/implicit_hasher.rs:70:22
@@ -90,9 +89,8 @@ LL | pub fn set(set: &mut HashSet<i32>) {}
    |
 help: add a type parameter for `BuildHasher`
    |
-LL - pub fn set(set: &mut HashSet<i32>) {}
-LL + pub fn set<S: ::std::hash::BuildHasher>(set: &mut HashSet<i32, S>) {}
-   |
+LL | pub fn set<S: ::std::hash::BuildHasher>(set: &mut HashSet<i32, S>) {}
+   |           +++++++++++++++++++++++++++++                      +++
 
 error: impl for `HashMap` should be generalized over different hashers
   --> tests/ui/implicit_hasher.rs:76:43
@@ -116,9 +114,8 @@ LL | pub async fn election_vote(_data: HashMap<i32, i32>) {}
    |
 help: add a type parameter for `BuildHasher`
    |
-LL - pub async fn election_vote(_data: HashMap<i32, i32>) {}
-LL + pub async fn election_vote<S: ::std::hash::BuildHasher>(_data: HashMap<i32, i32, S>) {}
-   |
+LL | pub async fn election_vote<S: ::std::hash::BuildHasher>(_data: HashMap<i32, i32, S>) {}
+   |                           +++++++++++++++++++++++++++++                        +++
 
 error: aborting due to 9 previous errors
 

tests/ui/implicit_return.stderr

@@ -9,7 +9,7 @@ LL |     true
 help: add `return` as shown
    |
 LL |     return true
-   |
+   |     ++++++
 
 error: missing `return` statement
   --> tests/ui/implicit_return.rs:19:15
@@ -122,7 +122,7 @@ LL |     format!("test {}", "test")
 help: add `return` as shown
    |
 LL |     return format!("test {}", "test")
-   |
+   |     ++++++
 
 error: missing `return` statement
   --> tests/ui/implicit_return.rs:90:5
@@ -133,7 +133,7 @@ LL |     m!(true, false)
 help: add `return` as shown
    |
 LL |     return m!(true, false)
-   |
+   |     ++++++
 
 error: missing `return` statement
   --> tests/ui/implicit_return.rs:96:13
@@ -169,10 +169,8 @@ LL | |     }
    |
 help: add `return` as shown
    |
-LL ~     return loop {
-LL +         m!(true);
-LL +     }
-   |
+LL |     return loop {
+   |     ++++++
 
 error: missing `return` statement
   --> tests/ui/implicit_return.rs:130:5
@@ -183,7 +181,7 @@ LL |     true
 help: add `return` as shown
    |
 LL |     return true
-   |
+   |     ++++++
 
 error: aborting due to 16 previous errors
 

tests/ui/literals.stderr

@@ -99,9 +99,8 @@ LL +     let fail8 = 123;
    |
 help: if you mean to use an octal constant, use `0o`
    |
-LL -     let fail8 = 0123;
-LL +     let fail8 = 0o123;
-   |
+LL |     let fail8 = 0o123;
+   |                  +
 
 error: integer type suffix should not be separated by an underscore
   --> tests/ui/literals.rs:48:16

tests/ui/manual_flatten.stderr

@@ -196,11 +196,9 @@ LL | |         }
    | |_________^
 help: try
    |
-LL ~     for n in vec![
-LL +
-LL +         Some(1),
-LL +         Some(2),
-LL +         Some(3)
+LL |     for n in vec![
+...
+LL |         Some(3)
 LL ~     ].iter().flatten() {
    |