review comments

- reword messages
- apply custom comments to all types of ranges
- fix indentation

src/libcore/iter/iterator.rs

@@ -33,8 +33,32 @@ fn _assert_is_object_safe(_: &dyn Iterator<Item=()>) {}
     on(
         _Self="[std::ops::Range<Idx>; 1]",
         label="if you meant to iterate between two values, remove the square brackets",
-        note="`[start..end]` is an array of one `Range`, you might have meant to have a `Range`: \
-              `start..end`"
+        note="`[start..end]` is an array of one `Range`; you might have meant to have a `Range` \
+              without the brackets: `start..end`"
+    ),
+    on(
+        _Self="[std::ops::RangeFrom<Idx>; 1]",
+        label="if you meant to iterate from a value onwards, remove the square brackets",
+        note="`[start..]` is an array of one `RangeFrom`; you might have meant to have a \
+              `RangeFrom` without the brackets: `start..`"
+    ),
+    on(
+        _Self="[std::ops::RangeTo<Idx>; 1]",
+        label="if you meant to iterate until a value, remove the square brackets",
+        note="`[..end]` is an array of one `RangeTo`; you might have meant to have a \
+              `RangeTo` without the brackets: `..end`"
+    ),
+    on(
+        _Self="[std::ops::RangeInclusive<Idx>; 1]",
+        label="if you meant to iterate between two values, remove the square brackets",
+        note="`[start..=end]` is an array of one `RangeInclusive`; you might have meant to have a \
+              `RangeInclusive` without the brackets: `start..=end`"
+    ),
+    on(
+        _Self="[std::ops::RangeToInclusive<Idx>; 1]",
+        label="if you meant to iterate until a value, remove the square brackets",
+        note="`[..=end]` is an array of one `RangeToInclusive`; you might have meant to have a \
+              `RangeToInclusive` without the brackets: `..=end`"
     ),
     on(
         _Self="&str",
@@ -51,8 +75,8 @@ fn _assert_is_object_safe(_: &dyn Iterator<Item=()>) {}
     ),
     on(
         _Self="{integral}",
-        note="if you want to iterate between `0` until a value `end`, use the range syntax: \
-              `0..end`"
+        note="if you want to iterate between `start` until a value `end`, use the exclusive range \
+              syntax `start..end` or the inclusive range syntax `start..=end`"
     ),
     label="`{Self}` is not an iterator",
     message="`{Self}` is not an iterator"

src/librustc/traits/error_reporting.rs

@@ -351,7 +351,7 @@ fn on_unimplemented_note(
         trait_ref: ty::PolyTraitRef<'tcx>,
         obligation: &PredicateObligation<'tcx>,
     ) -> OnUnimplementedNote {
-    let def_id = self.impl_similar_to(trait_ref, obligation)
+        let def_id = self.impl_similar_to(trait_ref, obligation)
             .unwrap_or(trait_ref.def_id());
         let trait_ref = *trait_ref.skip_binder();
 

src/test/ui/feature-gates/feature-gate-trivial_bounds.stderr

@@ -84,7 +84,7 @@ LL | | }
    | |_^ `i32` is not an iterator
    |
    = help: the trait `std::iter::Iterator` is not implemented for `i32`
-   = note: if you want to iterate between `0` until a value `end`, use the range syntax: `0..end`
+   = note: if you want to iterate between `start` until a value `end`, use the exclusive range syntax `start..end` or the inclusive range syntax `start..=end`
    = help: see issue #48214
    = help: add #![feature(trivial_bounds)] to the crate attributes to enable
 

src/test/ui/issues/issue-50480.stderr

@@ -11,7 +11,7 @@ LL | struct Foo(NotDefined, <i32 as Iterator>::Item, Vec<i32>, String);
    |                        ^^^^^^^^^^^^^^^^^^^^^^^ `i32` is not an iterator
    |
    = help: the trait `std::iter::Iterator` is not implemented for `i32`
-   = note: if you want to iterate between `0` until a value `end`, use the range syntax: `0..end`
+   = note: if you want to iterate between `start` until a value `end`, use the exclusive range syntax `start..end` or the inclusive range syntax `start..=end`
 
 error[E0204]: the trait `Copy` may not be implemented for this type
   --> $DIR/issue-50480.rs:11:17

src/test/ui/iterators/array-of-ranges.stderr

@@ -5,7 +5,7 @@ LL |     for _ in [0..1] {}
    |              ^^^^^^ if you meant to iterate between two values, remove the square brackets
    |
    = help: the trait `std::iter::Iterator` is not implemented for `[std::ops::Range<{integer}>; 1]`
-   = note: `[start..end]` is an array of one `Range`, you might have meant to have a `Range`: `start..end`
+   = note: `[start..end]` is an array of one `Range`; you might have meant to have a `Range` without the brackets: `start..end`
    = note: required by `std::iter::IntoIterator::into_iter`
 
 error[E0277]: `[std::ops::Range<{integer}>; 1]` is not an iterator
@@ -15,7 +15,7 @@ LL |     for _ in [start..end] {}
    |              ^^^^^^^^^^^^ if you meant to iterate between two values, remove the square brackets
    |
    = help: the trait `std::iter::Iterator` is not implemented for `[std::ops::Range<{integer}>; 1]`
-   = note: `[start..end]` is an array of one `Range`, you might have meant to have a `Range`: `start..end`
+   = note: `[start..end]` is an array of one `Range`; you might have meant to have a `Range` without the brackets: `start..end`
    = note: required by `std::iter::IntoIterator::into_iter`
 
 error[E0277]: `[std::ops::Range<{integer}>; 1]` is not an iterator
@@ -25,7 +25,7 @@ LL |     for _ in array_of_range {}
    |              ^^^^^^^^^^^^^^ if you meant to iterate between two values, remove the square brackets
    |
    = help: the trait `std::iter::Iterator` is not implemented for `[std::ops::Range<{integer}>; 1]`
-   = note: `[start..end]` is an array of one `Range`, you might have meant to have a `Range`: `start..end`
+   = note: `[start..end]` is an array of one `Range`; you might have meant to have a `Range` without the brackets: `start..end`
    = note: required by `std::iter::IntoIterator::into_iter`
 
 error[E0277]: `[std::ops::Range<{integer}>; 2]` is not an iterator

src/test/ui/iterators/bound.stderr

@@ -5,7 +5,7 @@ LL | struct T(S<u8>);
    |          ^^^^^ `u8` is not an iterator
    |
    = help: the trait `std::iter::Iterator` is not implemented for `u8`
-   = note: if you want to iterate between `0` until a value `end`, use the range syntax: `0..end`
+   = note: if you want to iterate between `start` until a value `end`, use the exclusive range syntax `start..end` or the inclusive range syntax `start..=end`
 note: required by `S`
   --> $DIR/bound.rs:1:1
    |

src/test/ui/iterators/integral.stderr

@@ -5,7 +5,7 @@ LL |     for _ in 42 {}
    |              ^^ `{integer}` is not an iterator
    |
    = help: the trait `std::iter::Iterator` is not implemented for `{integer}`
-   = note: if you want to iterate between `0` until a value `end`, use the range syntax: `0..end`
+   = note: if you want to iterate between `start` until a value `end`, use the exclusive range syntax `start..end` or the inclusive range syntax `start..=end`
    = note: required by `std::iter::IntoIterator::into_iter`
 
 error[E0277]: `u8` is not an iterator
@@ -15,7 +15,7 @@ LL |     for _ in 42 as u8 {}
    |              ^^^^^^^^ `u8` is not an iterator
    |
    = help: the trait `std::iter::Iterator` is not implemented for `u8`
-   = note: if you want to iterate between `0` until a value `end`, use the range syntax: `0..end`
+   = note: if you want to iterate between `start` until a value `end`, use the exclusive range syntax `start..end` or the inclusive range syntax `start..=end`
    = note: required by `std::iter::IntoIterator::into_iter`
 
 error[E0277]: `i8` is not an iterator
@@ -25,7 +25,7 @@ LL |     for _ in 42 as i8 {}
    |              ^^^^^^^^ `i8` is not an iterator
    |
    = help: the trait `std::iter::Iterator` is not implemented for `i8`
-   = note: if you want to iterate between `0` until a value `end`, use the range syntax: `0..end`
+   = note: if you want to iterate between `start` until a value `end`, use the exclusive range syntax `start..end` or the inclusive range syntax `start..=end`
    = note: required by `std::iter::IntoIterator::into_iter`
 
 error[E0277]: `u16` is not an iterator
@@ -35,7 +35,7 @@ LL |     for _ in 42 as u16 {}
    |              ^^^^^^^^^ `u16` is not an iterator
    |
    = help: the trait `std::iter::Iterator` is not implemented for `u16`
-   = note: if you want to iterate between `0` until a value `end`, use the range syntax: `0..end`
+   = note: if you want to iterate between `start` until a value `end`, use the exclusive range syntax `start..end` or the inclusive range syntax `start..=end`
    = note: required by `std::iter::IntoIterator::into_iter`
 
 error[E0277]: `i16` is not an iterator
@@ -45,7 +45,7 @@ LL |     for _ in 42 as i16 {}
    |              ^^^^^^^^^ `i16` is not an iterator
    |
    = help: the trait `std::iter::Iterator` is not implemented for `i16`
-   = note: if you want to iterate between `0` until a value `end`, use the range syntax: `0..end`
+   = note: if you want to iterate between `start` until a value `end`, use the exclusive range syntax `start..end` or the inclusive range syntax `start..=end`
    = note: required by `std::iter::IntoIterator::into_iter`
 
 error[E0277]: `u32` is not an iterator
@@ -55,7 +55,7 @@ LL |     for _ in 42 as u32 {}
    |              ^^^^^^^^^ `u32` is not an iterator
    |
    = help: the trait `std::iter::Iterator` is not implemented for `u32`
-   = note: if you want to iterate between `0` until a value `end`, use the range syntax: `0..end`
+   = note: if you want to iterate between `start` until a value `end`, use the exclusive range syntax `start..end` or the inclusive range syntax `start..=end`
    = note: required by `std::iter::IntoIterator::into_iter`
 
 error[E0277]: `i32` is not an iterator
@@ -65,7 +65,7 @@ LL |     for _ in 42 as i32 {}
    |              ^^^^^^^^^ `i32` is not an iterator
    |
    = help: the trait `std::iter::Iterator` is not implemented for `i32`
-   = note: if you want to iterate between `0` until a value `end`, use the range syntax: `0..end`
+   = note: if you want to iterate between `start` until a value `end`, use the exclusive range syntax `start..end` or the inclusive range syntax `start..=end`
    = note: required by `std::iter::IntoIterator::into_iter`
 
 error[E0277]: `u64` is not an iterator
@@ -75,7 +75,7 @@ LL |     for _ in 42 as u64 {}
    |              ^^^^^^^^^ `u64` is not an iterator
    |
    = help: the trait `std::iter::Iterator` is not implemented for `u64`
-   = note: if you want to iterate between `0` until a value `end`, use the range syntax: `0..end`
+   = note: if you want to iterate between `start` until a value `end`, use the exclusive range syntax `start..end` or the inclusive range syntax `start..=end`
    = note: required by `std::iter::IntoIterator::into_iter`
 
 error[E0277]: `i64` is not an iterator
@@ -85,7 +85,7 @@ LL |     for _ in 42 as i64 {}
    |              ^^^^^^^^^ `i64` is not an iterator
    |
    = help: the trait `std::iter::Iterator` is not implemented for `i64`
-   = note: if you want to iterate between `0` until a value `end`, use the range syntax: `0..end`
+   = note: if you want to iterate between `start` until a value `end`, use the exclusive range syntax `start..end` or the inclusive range syntax `start..=end`
    = note: required by `std::iter::IntoIterator::into_iter`
 
 error[E0277]: `usize` is not an iterator
@@ -95,7 +95,7 @@ LL |     for _ in 42 as usize {}
    |              ^^^^^^^^^^^ `usize` is not an iterator
    |
    = help: the trait `std::iter::Iterator` is not implemented for `usize`
-   = note: if you want to iterate between `0` until a value `end`, use the range syntax: `0..end`
+   = note: if you want to iterate between `start` until a value `end`, use the exclusive range syntax `start..end` or the inclusive range syntax `start..=end`
    = note: required by `std::iter::IntoIterator::into_iter`
 
 error[E0277]: `isize` is not an iterator
@@ -105,7 +105,7 @@ LL |     for _ in 42 as isize {}
    |              ^^^^^^^^^^^ `isize` is not an iterator
    |
    = help: the trait `std::iter::Iterator` is not implemented for `isize`
-   = note: if you want to iterate between `0` until a value `end`, use the range syntax: `0..end`
+   = note: if you want to iterate between `start` until a value `end`, use the exclusive range syntax `start..end` or the inclusive range syntax `start..=end`
    = note: required by `std::iter::IntoIterator::into_iter`
 
 error[E0277]: `{float}` is not an iterator