Auto merge of #48337 - GuillaumeGomez:rustc-explain, r=estebank

Rustc explain

Fixes #48041.

To make the review easier, I separated tests update to code update. Also, I used this script to generate new ui tests stderr:

```python
from os import listdir
from os.path import isdir, isfile, join

PATH = "src/test/ui"

def do_something(path):
    files = [join(path, f) for f in listdir(path)]

    for f in files:
        if isdir(f):
            do_something(f)
            continue
        if not isfile(f) or not f.endswith(".stderr"):
            continue
        x = open(f, "r")
        content = x.read().strip()
        if "error[E" not in content:
            continue
        errors = dict()
        for y in content.splitlines():
            if y.startswith("error[E"):
                errors[y[6:11]] = True
        errors = sorted(errors.keys())
        if len(errors) < 1:
            print("weird... {}".format(f))
            continue
        if len(errors) > 1:
            content += "\n\nYou've got a few errors: {}".format(", ".join(errors))
            content += "\nIf you want more information on an error, try using \"rustc --explain {}\"".format(errors[0])
        else:
            content += "\n\nIf you want more information on this error, try using \"rustc --explain {}\"".format(errors[0])
        content += "\n"
        x = open(f, "w")
        x.write(content)

do_something(PATH)
```

81 files changed, 88 insertions, 0 deletions

diff --git a/src/test/ui/span/E0046.stderr b/src/test/ui/span/E0046.stderr
index fb13f21fe00..02f2a8cfc6c 100644
--- a/src/test/ui/span/E0046.stderr
+++ b/src/test/ui/span/E0046.stderr
@@ -9,3 +9,4 @@ error[E0046]: not all trait items implemented, missing: `foo`
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0046"
diff --git a/src/test/ui/span/E0057.stderr b/src/test/ui/span/E0057.stderr
index 450c87ca032..f0c40578ddb 100644
--- a/src/test/ui/span/E0057.stderr
+++ b/src/test/ui/span/E0057.stderr
@@ -12,3 +12,4 @@ error[E0057]: this function takes 1 parameter but 2 parameters were supplied
 
 error: aborting due to 2 previous errors
 
+If you want more information on this error, try using "rustc --explain E0057"
diff --git a/src/test/ui/span/E0072.stderr b/src/test/ui/span/E0072.stderr
index 82b8579d5a1..22319e6552e 100644
--- a/src/test/ui/span/E0072.stderr
+++ b/src/test/ui/span/E0072.stderr
@@ -11,3 +11,4 @@ error[E0072]: recursive type `ListNode` has infinite size
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0072"
diff --git a/src/test/ui/span/E0204.stderr b/src/test/ui/span/E0204.stderr
index 0d9617c4c73..0c0d431f38f 100644
--- a/src/test/ui/span/E0204.stderr
+++ b/src/test/ui/span/E0204.stderr
@@ -36,3 +36,4 @@ error[E0204]: the trait `Copy` may not be implemented for this type
 
 error: aborting due to 4 previous errors
 
+If you want more information on this error, try using "rustc --explain E0204"
diff --git a/src/test/ui/span/E0493.stderr b/src/test/ui/span/E0493.stderr
index d7996eaef3a..c8bdd04394e 100644
--- a/src/test/ui/span/E0493.stderr
+++ b/src/test/ui/span/E0493.stderr
@@ -6,3 +6,4 @@ error[E0493]: destructors cannot be evaluated at compile-time
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0493"
diff --git a/src/test/ui/span/E0535.stderr b/src/test/ui/span/E0535.stderr
index 23070e1555b..e271a8018bc 100644
--- a/src/test/ui/span/E0535.stderr
+++ b/src/test/ui/span/E0535.stderr
@@ -6,3 +6,4 @@ error[E0535]: invalid argument
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0535"
diff --git a/src/test/ui/span/E0536.stderr b/src/test/ui/span/E0536.stderr
index c33b89953e2..9903896fd77 100644
--- a/src/test/ui/span/E0536.stderr
+++ b/src/test/ui/span/E0536.stderr
@@ -6,3 +6,4 @@ error[E0536]: expected 1 cfg-pattern
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0536"
diff --git a/src/test/ui/span/E0537.stderr b/src/test/ui/span/E0537.stderr
index 9d66ddbaae3..f08e7a7357b 100644
--- a/src/test/ui/span/E0537.stderr
+++ b/src/test/ui/span/E0537.stderr
@@ -6,3 +6,4 @@ error[E0537]: invalid predicate `unknown`
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0537"
diff --git a/src/test/ui/span/borrowck-borrow-overloaded-auto-deref-mut.stderr b/src/test/ui/span/borrowck-borrow-overloaded-auto-deref-mut.stderr
index 2d580e7c20e..3230766af8a 100644
--- a/src/test/ui/span/borrowck-borrow-overloaded-auto-deref-mut.stderr
+++ b/src/test/ui/span/borrowck-borrow-overloaded-auto-deref-mut.stderr
@@ -84,3 +84,5 @@ error[E0596]: cannot borrow immutable borrowed content `*x` as mutable
 
 error: aborting due to 10 previous errors
 
+You've got a few errors: E0499, E0596
+If you want more information on an error, try using "rustc --explain E0499"
diff --git a/src/test/ui/span/borrowck-borrow-overloaded-deref-mut.stderr b/src/test/ui/span/borrowck-borrow-overloaded-deref-mut.stderr
index 3d380a9a2e8..031d0e1e92d 100644
--- a/src/test/ui/span/borrowck-borrow-overloaded-deref-mut.stderr
+++ b/src/test/ui/span/borrowck-borrow-overloaded-deref-mut.stderr
@@ -32,3 +32,4 @@ error[E0596]: cannot borrow immutable borrowed content `*x` as mutable
 
 error: aborting due to 4 previous errors
 
+If you want more information on this error, try using "rustc --explain E0596"
diff --git a/src/test/ui/span/borrowck-call-is-borrow-issue-12224.stderr b/src/test/ui/span/borrowck-call-is-borrow-issue-12224.stderr
index 581b366af1c..adbe560f633 100644
--- a/src/test/ui/span/borrowck-call-is-borrow-issue-12224.stderr
+++ b/src/test/ui/span/borrowck-call-is-borrow-issue-12224.stderr
@@ -46,3 +46,5 @@ error[E0507]: cannot move out of captured outer variable in an `FnMut` closure
 
 error: aborting due to 5 previous errors
 
+You've got a few errors: E0499, E0504, E0507, E0596
+If you want more information on an error, try using "rustc --explain E0499"
diff --git a/src/test/ui/span/borrowck-call-method-from-mut-aliasable.stderr b/src/test/ui/span/borrowck-call-method-from-mut-aliasable.stderr
index a57cc94b9ba..6a4e030bc39 100644
--- a/src/test/ui/span/borrowck-call-method-from-mut-aliasable.stderr
+++ b/src/test/ui/span/borrowck-call-method-from-mut-aliasable.stderr
@@ -9,3 +9,4 @@ error[E0596]: cannot borrow immutable borrowed content `*x` as mutable
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0596"
diff --git a/src/test/ui/span/borrowck-fn-in-const-b.stderr b/src/test/ui/span/borrowck-fn-in-const-b.stderr
index 45712d1a710..749725bee56 100644
--- a/src/test/ui/span/borrowck-fn-in-const-b.stderr
+++ b/src/test/ui/span/borrowck-fn-in-const-b.stderr
@@ -8,3 +8,4 @@ error[E0596]: cannot borrow immutable borrowed content `*x` as mutable
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0596"
diff --git a/src/test/ui/span/borrowck-let-suggestion-suffixes.stderr b/src/test/ui/span/borrowck-let-suggestion-suffixes.stderr
index e65fd723e5f..fa33899816c 100644
--- a/src/test/ui/span/borrowck-let-suggestion-suffixes.stderr
+++ b/src/test/ui/span/borrowck-let-suggestion-suffixes.stderr
@@ -50,3 +50,4 @@ error[E0597]: borrowed value does not live long enough
 
 error: aborting due to 4 previous errors
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/borrowck-object-mutability.stderr b/src/test/ui/span/borrowck-object-mutability.stderr
index 530993f399a..1a510a5defc 100644
--- a/src/test/ui/span/borrowck-object-mutability.stderr
+++ b/src/test/ui/span/borrowck-object-mutability.stderr
@@ -18,3 +18,4 @@ error[E0596]: cannot borrow immutable `Box` content `*x` as mutable
 
 error: aborting due to 2 previous errors
 
+If you want more information on this error, try using "rustc --explain E0596"
diff --git a/src/test/ui/span/borrowck-ref-into-rvalue.stderr b/src/test/ui/span/borrowck-ref-into-rvalue.stderr
index 80ddd150757..a91cb2def15 100644
--- a/src/test/ui/span/borrowck-ref-into-rvalue.stderr
+++ b/src/test/ui/span/borrowck-ref-into-rvalue.stderr
@@ -14,3 +14,4 @@ error[E0597]: borrowed value does not live long enough
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/coerce-suggestions.stderr b/src/test/ui/span/coerce-suggestions.stderr
index 06f0e6ec228..396bbe4793c 100644
--- a/src/test/ui/span/coerce-suggestions.stderr
+++ b/src/test/ui/span/coerce-suggestions.stderr
@@ -61,3 +61,4 @@ error[E0308]: mismatched types
 
 error: aborting due to 6 previous errors
 
+If you want more information on this error, try using "rustc --explain E0308"
diff --git a/src/test/ui/span/destructor-restrictions.stderr b/src/test/ui/span/destructor-restrictions.stderr
index abe982c5ce3..e9fede39b91 100644
--- a/src/test/ui/span/destructor-restrictions.stderr
+++ b/src/test/ui/span/destructor-restrictions.stderr
@@ -10,3 +10,4 @@ error[E0597]: `*a` does not live long enough
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/dropck-object-cycle.stderr b/src/test/ui/span/dropck-object-cycle.stderr
index 2b760415a1a..39f8bd9f9e2 100644
--- a/src/test/ui/span/dropck-object-cycle.stderr
+++ b/src/test/ui/span/dropck-object-cycle.stderr
@@ -11,3 +11,4 @@ error[E0597]: `*m` does not live long enough
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/dropck_arr_cycle_checked.stderr b/src/test/ui/span/dropck_arr_cycle_checked.stderr
index 1225c36ab3d..412cc6f35f0 100644
--- a/src/test/ui/span/dropck_arr_cycle_checked.stderr
+++ b/src/test/ui/span/dropck_arr_cycle_checked.stderr
@@ -66,3 +66,4 @@ error[E0597]: `b2` does not live long enough
 
 error: aborting due to 6 previous errors
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/dropck_direct_cycle_with_drop.stderr b/src/test/ui/span/dropck_direct_cycle_with_drop.stderr
index 462b291f4fa..e6ea657b2e9 100644
--- a/src/test/ui/span/dropck_direct_cycle_with_drop.stderr
+++ b/src/test/ui/span/dropck_direct_cycle_with_drop.stderr
@@ -22,3 +22,4 @@ error[E0597]: `d1` does not live long enough
 
 error: aborting due to 2 previous errors
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/dropck_misc_variants.stderr b/src/test/ui/span/dropck_misc_variants.stderr
index b839701f08b..d1c91430cf8 100644
--- a/src/test/ui/span/dropck_misc_variants.stderr
+++ b/src/test/ui/span/dropck_misc_variants.stderr
@@ -21,3 +21,4 @@ error[E0597]: `v` does not live long enough
 
 error: aborting due to 2 previous errors
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/dropck_vec_cycle_checked.stderr b/src/test/ui/span/dropck_vec_cycle_checked.stderr
index 799dfb8e201..1171d3972bf 100644
--- a/src/test/ui/span/dropck_vec_cycle_checked.stderr
+++ b/src/test/ui/span/dropck_vec_cycle_checked.stderr
@@ -66,3 +66,4 @@ error[E0597]: `c2` does not live long enough
 
 error: aborting due to 6 previous errors
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/gated-features-attr-spans.stderr b/src/test/ui/span/gated-features-attr-spans.stderr
index f15c4a72c5a..f99dafed27a 100644
--- a/src/test/ui/span/gated-features-attr-spans.stderr
+++ b/src/test/ui/span/gated-features-attr-spans.stderr
@@ -24,3 +24,4 @@ warning: `#[must_use]` on functions is experimental (see issue #43302)
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0658"
diff --git a/src/test/ui/span/impl-wrong-item-for-trait.stderr b/src/test/ui/span/impl-wrong-item-for-trait.stderr
index 6473b24dec5..95114577dc3 100644
--- a/src/test/ui/span/impl-wrong-item-for-trait.stderr
+++ b/src/test/ui/span/impl-wrong-item-for-trait.stderr
@@ -68,3 +68,5 @@ error[E0046]: not all trait items implemented, missing: `fmt`
 
 error: aborting due to 8 previous errors
 
+You've got a few errors: E0046, E0323, E0324, E0325, E0437
+If you want more information on an error, try using "rustc --explain E0046"
diff --git a/src/test/ui/span/issue-11925.stderr b/src/test/ui/span/issue-11925.stderr
index 01cd7661fb7..9e5d5acb862 100644
--- a/src/test/ui/span/issue-11925.stderr
+++ b/src/test/ui/span/issue-11925.stderr
@@ -12,3 +12,4 @@ error[E0597]: `x` does not live long enough
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/issue-15480.stderr b/src/test/ui/span/issue-15480.stderr
index 28841fbea97..35a7390cf5c 100644
--- a/src/test/ui/span/issue-15480.stderr
+++ b/src/test/ui/span/issue-15480.stderr
@@ -13,3 +13,4 @@ error[E0597]: borrowed value does not live long enough
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/issue-23338-locals-die-before-temps-of-body.stderr b/src/test/ui/span/issue-23338-locals-die-before-temps-of-body.stderr
index 1c9a64bc213..71a83fe3cc9 100644
--- a/src/test/ui/span/issue-23338-locals-die-before-temps-of-body.stderr
+++ b/src/test/ui/span/issue-23338-locals-die-before-temps-of-body.stderr
@@ -20,3 +20,4 @@ error[E0597]: `y` does not live long enough
 
 error: aborting due to 2 previous errors
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/issue-23729.stderr b/src/test/ui/span/issue-23729.stderr
index 60bf804ff30..6d112864b03 100644
--- a/src/test/ui/span/issue-23729.stderr
+++ b/src/test/ui/span/issue-23729.stderr
@@ -8,3 +8,4 @@ error[E0046]: not all trait items implemented, missing: `Item`
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0046"
diff --git a/src/test/ui/span/issue-23827.stderr b/src/test/ui/span/issue-23827.stderr
index d06d6c03616..7f58fe45e62 100644
--- a/src/test/ui/span/issue-23827.stderr
+++ b/src/test/ui/span/issue-23827.stderr
@@ -8,3 +8,4 @@ error[E0046]: not all trait items implemented, missing: `Output`
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0046"
diff --git a/src/test/ui/span/issue-24356.stderr b/src/test/ui/span/issue-24356.stderr
index 58fb943fef8..c529b258cb4 100644
--- a/src/test/ui/span/issue-24356.stderr
+++ b/src/test/ui/span/issue-24356.stderr
@@ -8,3 +8,4 @@ error[E0046]: not all trait items implemented, missing: `Target`
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0046"
diff --git a/src/test/ui/span/issue-24805-dropck-child-has-items-via-parent.stderr b/src/test/ui/span/issue-24805-dropck-child-has-items-via-parent.stderr
index f61a0919501..3c6371aa968 100644
--- a/src/test/ui/span/issue-24805-dropck-child-has-items-via-parent.stderr
+++ b/src/test/ui/span/issue-24805-dropck-child-has-items-via-parent.stderr
@@ -11,3 +11,4 @@ error[E0597]: `d1` does not live long enough
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/issue-24805-dropck-trait-has-items.stderr b/src/test/ui/span/issue-24805-dropck-trait-has-items.stderr
index 662ec58805d..fcec340a70e 100644
--- a/src/test/ui/span/issue-24805-dropck-trait-has-items.stderr
+++ b/src/test/ui/span/issue-24805-dropck-trait-has-items.stderr
@@ -30,3 +30,4 @@ error[E0597]: `d1` does not live long enough
 
 error: aborting due to 3 previous errors
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/issue-24895-copy-clone-dropck.stderr b/src/test/ui/span/issue-24895-copy-clone-dropck.stderr
index 1c68cacad7c..b10f5d7da1f 100644
--- a/src/test/ui/span/issue-24895-copy-clone-dropck.stderr
+++ b/src/test/ui/span/issue-24895-copy-clone-dropck.stderr
@@ -10,3 +10,4 @@ error[E0597]: `d1` does not live long enough
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/issue-25199.stderr b/src/test/ui/span/issue-25199.stderr
index af02e9d6d54..0a768468c51 100644
--- a/src/test/ui/span/issue-25199.stderr
+++ b/src/test/ui/span/issue-25199.stderr
@@ -22,3 +22,4 @@ error[E0597]: `container` does not live long enough
 
 error: aborting due to 2 previous errors
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/issue-26656.stderr b/src/test/ui/span/issue-26656.stderr
index 1d632271f81..a1124e6e8ed 100644
--- a/src/test/ui/span/issue-26656.stderr
+++ b/src/test/ui/span/issue-26656.stderr
@@ -10,3 +10,4 @@ error[E0597]: `ticking` does not live long enough
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/issue-27522.stderr b/src/test/ui/span/issue-27522.stderr
index dc02ad73ee2..4c816e047de 100644
--- a/src/test/ui/span/issue-27522.stderr
+++ b/src/test/ui/span/issue-27522.stderr
@@ -9,3 +9,4 @@ error[E0307]: invalid `self` type: &SomeType
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0307"
diff --git a/src/test/ui/span/issue-29106.stderr b/src/test/ui/span/issue-29106.stderr
index 24042e23fef..3d3aab1166c 100644
--- a/src/test/ui/span/issue-29106.stderr
+++ b/src/test/ui/span/issue-29106.stderr
@@ -20,3 +20,4 @@ error[E0597]: `x` does not live long enough
 
 error: aborting due to 2 previous errors
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/issue-29595.stderr b/src/test/ui/span/issue-29595.stderr
index 9046b90f0e9..61c46f1a4b9 100644
--- a/src/test/ui/span/issue-29595.stderr
+++ b/src/test/ui/span/issue-29595.stderr
@@ -12,3 +12,4 @@ note: required by `Tr::C`
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0277"
diff --git a/src/test/ui/span/issue-33884.stderr b/src/test/ui/span/issue-33884.stderr
index 5a9c2051a71..48d697e7731 100644
--- a/src/test/ui/span/issue-33884.stderr
+++ b/src/test/ui/span/issue-33884.stderr
@@ -10,3 +10,4 @@ error[E0308]: mismatched types
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0308"
diff --git a/src/test/ui/span/issue-34264.stderr b/src/test/ui/span/issue-34264.stderr
index 18860a7456e..eb2b1b84201 100644
--- a/src/test/ui/span/issue-34264.stderr
+++ b/src/test/ui/span/issue-34264.stderr
@@ -45,3 +45,5 @@ error[E0061]: this function takes 2 parameters but 3 parameters were supplied
 
 error: aborting due to 6 previous errors
 
+You've got a few errors: E0061, E0308
+If you want more information on an error, try using "rustc --explain E0061"
diff --git a/src/test/ui/span/issue-35987.stderr b/src/test/ui/span/issue-35987.stderr
index 5e7a492ca2a..5b09342456e 100644
--- a/src/test/ui/span/issue-35987.stderr
+++ b/src/test/ui/span/issue-35987.stderr
@@ -12,3 +12,5 @@ error[E0601]: main function not found
 
 error: cannot continue compilation due to previous error
 
+You've got a few errors: E0404, E0601
+If you want more information on an error, try using "rustc --explain E0404"
diff --git a/src/test/ui/span/issue-36530.stderr b/src/test/ui/span/issue-36530.stderr
index 7f392104393..8a9375a32e5 100644
--- a/src/test/ui/span/issue-36530.stderr
+++ b/src/test/ui/span/issue-36530.stderr
@@ -16,3 +16,4 @@ error[E0658]: The attribute `foo` is currently unknown to the compiler and may h
 
 error: aborting due to 2 previous errors
 
+If you want more information on this error, try using "rustc --explain E0658"
diff --git a/src/test/ui/span/issue-36537.stderr b/src/test/ui/span/issue-36537.stderr
index 255700a55f3..24cabe55d0d 100644
--- a/src/test/ui/span/issue-36537.stderr
+++ b/src/test/ui/span/issue-36537.stderr
@@ -11,3 +11,4 @@ error[E0597]: `a` does not live long enough
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/issue-37767.stderr b/src/test/ui/span/issue-37767.stderr
index e9a1fe82f14..eab278d607b 100644
--- a/src/test/ui/span/issue-37767.stderr
+++ b/src/test/ui/span/issue-37767.stderr
@@ -57,3 +57,4 @@ note: candidate #2 is defined in the trait `F`
 
 error: aborting due to 3 previous errors
 
+If you want more information on this error, try using "rustc --explain E0034"
diff --git a/src/test/ui/span/issue-39018.stderr b/src/test/ui/span/issue-39018.stderr
index 70f8ecf42cb..e841dfc5840 100644
--- a/src/test/ui/span/issue-39018.stderr
+++ b/src/test/ui/span/issue-39018.stderr
@@ -32,3 +32,4 @@ help: you also need to borrow the `String` on the right to get a `&str`
 
 error: aborting due to 3 previous errors
 
+If you want more information on this error, try using "rustc --explain E0369"
diff --git a/src/test/ui/span/issue-39698.stderr b/src/test/ui/span/issue-39698.stderr
index 97d802f8398..888eb405a64 100644
--- a/src/test/ui/span/issue-39698.stderr
+++ b/src/test/ui/span/issue-39698.stderr
@@ -40,3 +40,4 @@ error[E0408]: variable `c` is not bound in all patterns
 
 error: aborting due to 4 previous errors
 
+If you want more information on this error, try using "rustc --explain E0408"
diff --git a/src/test/ui/span/issue-40157.stderr b/src/test/ui/span/issue-40157.stderr
index cf33ccf8095..fa5036ae5a4 100644
--- a/src/test/ui/span/issue-40157.stderr
+++ b/src/test/ui/span/issue-40157.stderr
@@ -12,3 +12,4 @@ error[E0597]: `foo` does not live long enough
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/issue-42234-unknown-receiver-type.stderr b/src/test/ui/span/issue-42234-unknown-receiver-type.stderr
index d87cec642f1..567d8f33ed6 100644
--- a/src/test/ui/span/issue-42234-unknown-receiver-type.stderr
+++ b/src/test/ui/span/issue-42234-unknown-receiver-type.stderr
@@ -15,3 +15,4 @@ error[E0282]: type annotations needed
 
 error: aborting due to 2 previous errors
 
+If you want more information on this error, try using "rustc --explain E0282"
diff --git a/src/test/ui/span/issue-7575.stderr b/src/test/ui/span/issue-7575.stderr
index aeb98e4cabc..df078c1330c 100644
--- a/src/test/ui/span/issue-7575.stderr
+++ b/src/test/ui/span/issue-7575.stderr
@@ -67,3 +67,4 @@ note: candidate #1 is defined in the trait `ManyImplTrait`
 
 error: aborting due to 3 previous errors
 
+If you want more information on this error, try using "rustc --explain E0599"
diff --git a/src/test/ui/span/issue28498-reject-ex1.stderr b/src/test/ui/span/issue28498-reject-ex1.stderr
index 8ade2f38eee..3504adc1602 100644
--- a/src/test/ui/span/issue28498-reject-ex1.stderr
+++ b/src/test/ui/span/issue28498-reject-ex1.stderr
@@ -22,3 +22,4 @@ error[E0597]: `foo.data` does not live long enough
 
 error: aborting due to 2 previous errors
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/issue28498-reject-lifetime-param.stderr b/src/test/ui/span/issue28498-reject-lifetime-param.stderr
index eb287265dac..5b4a1129d79 100644
--- a/src/test/ui/span/issue28498-reject-lifetime-param.stderr
+++ b/src/test/ui/span/issue28498-reject-lifetime-param.stderr
@@ -22,3 +22,4 @@ error[E0597]: `first_dropped` does not live long enough
 
 error: aborting due to 2 previous errors
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/issue28498-reject-passed-to-fn.stderr b/src/test/ui/span/issue28498-reject-passed-to-fn.stderr
index 53e0e02319f..a7497a1de01 100644
--- a/src/test/ui/span/issue28498-reject-passed-to-fn.stderr
+++ b/src/test/ui/span/issue28498-reject-passed-to-fn.stderr
@@ -22,3 +22,4 @@ error[E0597]: `first_dropped` does not live long enough
 
 error: aborting due to 2 previous errors
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/issue28498-reject-trait-bound.stderr b/src/test/ui/span/issue28498-reject-trait-bound.stderr
index 6b53745bbc8..18512847238 100644
--- a/src/test/ui/span/issue28498-reject-trait-bound.stderr
+++ b/src/test/ui/span/issue28498-reject-trait-bound.stderr
@@ -22,3 +22,4 @@ error[E0597]: `first_dropped` does not live long enough
 
 error: aborting due to 2 previous errors
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/loan-extend.stderr b/src/test/ui/span/loan-extend.stderr
index 280ddd6581a..af498129fc4 100644
--- a/src/test/ui/span/loan-extend.stderr
+++ b/src/test/ui/span/loan-extend.stderr
@@ -11,3 +11,4 @@ error[E0597]: `short` does not live long enough
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/missing-unit-argument.stderr b/src/test/ui/span/missing-unit-argument.stderr
index 77d037d497b..752087ffb92 100644
--- a/src/test/ui/span/missing-unit-argument.stderr
+++ b/src/test/ui/span/missing-unit-argument.stderr
@@ -67,3 +67,4 @@ help: expected the unit value `()`; create it with empty parentheses
 
 error: aborting due to 6 previous errors
 
+If you want more information on this error, try using "rustc --explain E0061"
diff --git a/src/test/ui/span/move-closure.stderr b/src/test/ui/span/move-closure.stderr
index 9135a26bbaf..f8f17404cf2 100644
--- a/src/test/ui/span/move-closure.stderr
+++ b/src/test/ui/span/move-closure.stderr
@@ -9,3 +9,4 @@ error[E0308]: mismatched types
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0308"
diff --git a/src/test/ui/span/multiline-span-E0072.stderr b/src/test/ui/span/multiline-span-E0072.stderr
index 124a53219a9..314c52e59d3 100644
--- a/src/test/ui/span/multiline-span-E0072.stderr
+++ b/src/test/ui/span/multiline-span-E0072.stderr
@@ -14,3 +14,4 @@ error[E0072]: recursive type `ListNode` has infinite size
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0072"
diff --git a/src/test/ui/span/multiline-span-simple.stderr b/src/test/ui/span/multiline-span-simple.stderr
index a18dfeb31d9..b1e48069fed 100644
--- a/src/test/ui/span/multiline-span-simple.stderr
+++ b/src/test/ui/span/multiline-span-simple.stderr
@@ -8,3 +8,4 @@ error[E0277]: cannot add `()` to `u32`
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0277"
diff --git a/src/test/ui/span/mut-arg-hint.stderr b/src/test/ui/span/mut-arg-hint.stderr
index 02c607ddc37..e79ca70f3d2 100644
--- a/src/test/ui/span/mut-arg-hint.stderr
+++ b/src/test/ui/span/mut-arg-hint.stderr
@@ -24,3 +24,4 @@ error[E0596]: cannot borrow immutable borrowed content `*a` as mutable
 
 error: aborting due to 3 previous errors
 
+If you want more information on this error, try using "rustc --explain E0596"
diff --git a/src/test/ui/span/mut-ptr-cant-outlive-ref.stderr b/src/test/ui/span/mut-ptr-cant-outlive-ref.stderr
index e39af850174..c08d15cd570 100644
--- a/src/test/ui/span/mut-ptr-cant-outlive-ref.stderr
+++ b/src/test/ui/span/mut-ptr-cant-outlive-ref.stderr
@@ -11,3 +11,4 @@ error[E0597]: `b` does not live long enough
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/non-existing-module-import.stderr b/src/test/ui/span/non-existing-module-import.stderr
index 74f5dac4937..2b45d92724c 100644
--- a/src/test/ui/span/non-existing-module-import.stderr
+++ b/src/test/ui/span/non-existing-module-import.stderr
@@ -6,3 +6,4 @@ error[E0432]: unresolved import `std::bar`
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0432"
diff --git a/src/test/ui/span/pub-struct-field.stderr b/src/test/ui/span/pub-struct-field.stderr
index 5b303758d2b..fe19259a140 100644
--- a/src/test/ui/span/pub-struct-field.stderr
+++ b/src/test/ui/span/pub-struct-field.stderr
@@ -17,3 +17,4 @@ error[E0124]: field `bar` is already declared
 
 error: aborting due to 2 previous errors
 
+If you want more information on this error, try using "rustc --explain E0124"
diff --git a/src/test/ui/span/range-2.stderr b/src/test/ui/span/range-2.stderr
index 106a8a7667f..e580022dfcb 100644
--- a/src/test/ui/span/range-2.stderr
+++ b/src/test/ui/span/range-2.stderr
@@ -22,3 +22,4 @@ error[E0597]: `b` does not live long enough
 
 error: aborting due to 2 previous errors
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/recursive-type-field.stderr b/src/test/ui/span/recursive-type-field.stderr
index bd9f5f032ef..6b8f6530233 100644
--- a/src/test/ui/span/recursive-type-field.stderr
+++ b/src/test/ui/span/recursive-type-field.stderr
@@ -29,3 +29,4 @@ error[E0072]: recursive type `Bar` has infinite size
 
 error: aborting due to 2 previous errors
 
+If you want more information on this error, try using "rustc --explain E0072"
diff --git a/src/test/ui/span/regionck-unboxed-closure-lifetimes.stderr b/src/test/ui/span/regionck-unboxed-closure-lifetimes.stderr
index ca453c22cce..c437fd1b48a 100644
--- a/src/test/ui/span/regionck-unboxed-closure-lifetimes.stderr
+++ b/src/test/ui/span/regionck-unboxed-closure-lifetimes.stderr
@@ -11,3 +11,4 @@ error[E0597]: `c` does not live long enough
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/regions-close-over-borrowed-ref-in-obj.stderr b/src/test/ui/span/regions-close-over-borrowed-ref-in-obj.stderr
index 12f70676220..19290139efc 100644
--- a/src/test/ui/span/regions-close-over-borrowed-ref-in-obj.stderr
+++ b/src/test/ui/span/regions-close-over-borrowed-ref-in-obj.stderr
@@ -11,3 +11,4 @@ error[E0597]: borrowed value does not live long enough
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/regions-close-over-type-parameter-2.stderr b/src/test/ui/span/regions-close-over-type-parameter-2.stderr
index b90e67d5a3c..f4a7ed61928 100644
--- a/src/test/ui/span/regions-close-over-type-parameter-2.stderr
+++ b/src/test/ui/span/regions-close-over-type-parameter-2.stderr
@@ -11,3 +11,4 @@ error[E0597]: `tmp0` does not live long enough
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/regions-escape-loop-via-variable.stderr b/src/test/ui/span/regions-escape-loop-via-variable.stderr
index 8cdf4e2d822..780276d770e 100644
--- a/src/test/ui/span/regions-escape-loop-via-variable.stderr
+++ b/src/test/ui/span/regions-escape-loop-via-variable.stderr
@@ -11,3 +11,4 @@ error[E0597]: `x` does not live long enough
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/regions-escape-loop-via-vec.stderr b/src/test/ui/span/regions-escape-loop-via-vec.stderr
index 73ff449b2b5..71fc4c24ebd 100644
--- a/src/test/ui/span/regions-escape-loop-via-vec.stderr
+++ b/src/test/ui/span/regions-escape-loop-via-vec.stderr
@@ -37,3 +37,5 @@ error[E0506]: cannot assign to `x` because it is borrowed
 
 error: aborting due to 4 previous errors
 
+You've got a few errors: E0503, E0506, E0597
+If you want more information on an error, try using "rustc --explain E0503"
diff --git a/src/test/ui/span/regions-infer-borrow-scope-within-loop.stderr b/src/test/ui/span/regions-infer-borrow-scope-within-loop.stderr
index 1fc7e05f496..10b6c05b5f4 100644
--- a/src/test/ui/span/regions-infer-borrow-scope-within-loop.stderr
+++ b/src/test/ui/span/regions-infer-borrow-scope-within-loop.stderr
@@ -12,3 +12,4 @@ error[E0597]: `*x` does not live long enough
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/send-is-not-static-ensures-scoping.stderr b/src/test/ui/span/send-is-not-static-ensures-scoping.stderr
index 657682d962d..5d8e4ff86ee 100644
--- a/src/test/ui/span/send-is-not-static-ensures-scoping.stderr
+++ b/src/test/ui/span/send-is-not-static-ensures-scoping.stderr
@@ -26,3 +26,4 @@ error[E0597]: `y` does not live long enough
 
 error: aborting due to 2 previous errors
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/send-is-not-static-std-sync-2.stderr b/src/test/ui/span/send-is-not-static-std-sync-2.stderr
index af8b7aeaa63..2d7e4667a40 100644
--- a/src/test/ui/span/send-is-not-static-std-sync-2.stderr
+++ b/src/test/ui/span/send-is-not-static-std-sync-2.stderr
@@ -34,3 +34,4 @@ error[E0597]: `x` does not live long enough
 
 error: aborting due to 3 previous errors
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/send-is-not-static-std-sync.stderr b/src/test/ui/span/send-is-not-static-std-sync.stderr
index 7c61398a864..66e2abba710 100644
--- a/src/test/ui/span/send-is-not-static-std-sync.stderr
+++ b/src/test/ui/span/send-is-not-static-std-sync.stderr
@@ -57,3 +57,5 @@ error[E0505]: cannot move out of `y` because it is borrowed
 
 error: aborting due to 6 previous errors
 
+You've got a few errors: E0505, E0597
+If you want more information on an error, try using "rustc --explain E0505"
diff --git a/src/test/ui/span/slice-borrow.stderr b/src/test/ui/span/slice-borrow.stderr
index 540aae0983a..6f6a187a075 100644
--- a/src/test/ui/span/slice-borrow.stderr
+++ b/src/test/ui/span/slice-borrow.stderr
@@ -13,3 +13,4 @@ error[E0597]: borrowed value does not live long enough
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/suggestion-non-ascii.stderr b/src/test/ui/span/suggestion-non-ascii.stderr
index 9ee8ccb01d0..02c0b73c0c7 100644
--- a/src/test/ui/span/suggestion-non-ascii.stderr
+++ b/src/test/ui/span/suggestion-non-ascii.stderr
@@ -6,3 +6,4 @@ error[E0608]: cannot index into a value of type `({integer},)`
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0608"
diff --git a/src/test/ui/span/type-binding.stderr b/src/test/ui/span/type-binding.stderr
index dc37acaf3f9..984504071ac 100644
--- a/src/test/ui/span/type-binding.stderr
+++ b/src/test/ui/span/type-binding.stderr
@@ -6,3 +6,4 @@ error[E0220]: associated type `Trget` not found for `std::ops::Deref`
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0220"
diff --git a/src/test/ui/span/typo-suggestion.stderr b/src/test/ui/span/typo-suggestion.stderr
index 2a084b1ae67..31247bddbc8 100644
--- a/src/test/ui/span/typo-suggestion.stderr
+++ b/src/test/ui/span/typo-suggestion.stderr
@@ -12,3 +12,4 @@ error[E0425]: cannot find value `fob` in this scope
 
 error: aborting due to 2 previous errors
 
+If you want more information on this error, try using "rustc --explain E0425"
diff --git a/src/test/ui/span/vec-must-not-hide-type-from-dropck.stderr b/src/test/ui/span/vec-must-not-hide-type-from-dropck.stderr
index cc8e58179ed..26417e94b8b 100644
--- a/src/test/ui/span/vec-must-not-hide-type-from-dropck.stderr
+++ b/src/test/ui/span/vec-must-not-hide-type-from-dropck.stderr
@@ -22,3 +22,4 @@ error[E0597]: `c1` does not live long enough
 
 error: aborting due to 2 previous errors
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/vec_refs_data_with_early_death.stderr b/src/test/ui/span/vec_refs_data_with_early_death.stderr
index acfc7babe01..8402826a0bc 100644
--- a/src/test/ui/span/vec_refs_data_with_early_death.stderr
+++ b/src/test/ui/span/vec_refs_data_with_early_death.stderr
@@ -22,3 +22,4 @@ error[E0597]: `y` does not live long enough
 
 error: aborting due to 2 previous errors
 
+If you want more information on this error, try using "rustc --explain E0597"
diff --git a/src/test/ui/span/wf-method-late-bound-regions.stderr b/src/test/ui/span/wf-method-late-bound-regions.stderr
index 8dd77259035..a0fe9d1ae18 100644
--- a/src/test/ui/span/wf-method-late-bound-regions.stderr
+++ b/src/test/ui/span/wf-method-late-bound-regions.stderr
@@ -11,3 +11,4 @@ error[E0597]: `pointer` does not live long enough
 
 error: aborting due to previous error
 
+If you want more information on this error, try using "rustc --explain E0597"