Auto merge of #46168 - durka:macro-backtrace, r=durka

mention nightly in -Z external-macro-backtrace note

Fix #46167 by mentioning that you need nightly in the message that tells you to pass `-Z external-macro-backtrace`.

Rationale:

1. The reason for having this message is to increase discoverability of the functionality. If the message is only shown on nightly it's less disoverable.
2. The same approach is taken if you call a const fn in const context without its feature gate (previously, if you called it without `#![feature(const_fn)]`).

cc @kennytm

21 files changed, 32 insertions, 31 deletions

diff --git a/src/librustc_errors/emitter.rs b/src/librustc_errors/emitter.rs
index 17ed1734fe2..389626a87ee 100644
--- a/src/librustc_errors/emitter.rs
+++ b/src/librustc_errors/emitter.rs
@@ -798,7 +798,8 @@ impl EmitterWriter {
                 level: Level::Note,
                 message: vec![
                     (["this error originates in a macro outside of the current crate",
-                      "(run with -Z external-macro-backtrace for more info)"].join(" "),
+                      "(in Nightly builds, run with -Z external-macro-backtrace for more info)"]
+                      .join(" "),
                      Style::NoStyle),
                 ],
                 span: MultiSpan::new(),
diff --git a/src/test/ui-fulldeps/issue-44953/issue-44953.stderr b/src/test/ui-fulldeps/issue-44953/issue-44953.stderr
index 4493ec14024..e0e96ec3f4f 100644
--- a/src/test/ui-fulldeps/issue-44953/issue-44953.stderr
+++ b/src/test/ui-fulldeps/issue-44953/issue-44953.stderr
@@ -13,7 +13,7 @@ error: use of unstable library feature 'rustc_private': this crate is being load
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: add #![feature(rustc_private)] to the crate attributes to enable
-   = note: this error originates in a macro outside of the current crate (run with -Z external-macro-backtrace for more info)
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/codemap_tests/bad-format-args.stderr b/src/test/ui/codemap_tests/bad-format-args.stderr
index 7faabc6b3a6..9d6ef54cb97 100644
--- a/src/test/ui/codemap_tests/bad-format-args.stderr
+++ b/src/test/ui/codemap_tests/bad-format-args.stderr
@@ -4,7 +4,7 @@ error: requires at least a format string argument
 12 |     format!();
    |     ^^^^^^^^^^
    |
-   = note: this error originates in a macro outside of the current crate (run with -Z external-macro-backtrace for more info)
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: expected token: `,`
   --> $DIR/bad-format-args.rs:13:5
@@ -12,7 +12,7 @@ error: expected token: `,`
 13 |     format!("" 1);
    |     ^^^^^^^^^^^^^^
    |
-   = note: this error originates in a macro outside of the current crate (run with -Z external-macro-backtrace for more info)
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: expected token: `,`
   --> $DIR/bad-format-args.rs:14:5
@@ -20,7 +20,7 @@ error: expected token: `,`
 14 |     format!("", 1 1);
    |     ^^^^^^^^^^^^^^^^^
    |
-   = note: this error originates in a macro outside of the current crate (run with -Z external-macro-backtrace for more info)
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/codemap_tests/issue-28308.stderr b/src/test/ui/codemap_tests/issue-28308.stderr
index bb91bbbc9e3..c5afa5ec1a4 100644
--- a/src/test/ui/codemap_tests/issue-28308.stderr
+++ b/src/test/ui/codemap_tests/issue-28308.stderr
@@ -4,7 +4,7 @@ error[E0600]: cannot apply unary operator `!` to type `&'static str`
 12 |     assert!("foo");
    |     ^^^^^^^^^^^^^^^
    |
-   = note: this error originates in a macro outside of the current crate (run with -Z external-macro-backtrace for more info)
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/cross-crate-macro-backtrace/main.stderr b/src/test/ui/cross-crate-macro-backtrace/main.stderr
index 3644c0468d6..fc2343bdb1d 100644
--- a/src/test/ui/cross-crate-macro-backtrace/main.stderr
+++ b/src/test/ui/cross-crate-macro-backtrace/main.stderr
@@ -4,7 +4,7 @@ error: 1 positional argument in format string, but no arguments were given
 18 |     myprintln!("{}");
    |     ^^^^^^^^^^^^^^^^^
    |
-   = note: this error originates in a macro outside of the current crate (run with -Z external-macro-backtrace for more info)
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/fmt/format-string-error.stderr b/src/test/ui/fmt/format-string-error.stderr
index 1da8833e0f8..1c775929cf4 100644
--- a/src/test/ui/fmt/format-string-error.stderr
+++ b/src/test/ui/fmt/format-string-error.stderr
@@ -5,7 +5,7 @@ error: invalid format string: expected `'}'` but string was terminated
    |     ^^^^^^^^^^^^^^
    |
    = note: if you intended to print `{`, you can escape it using `{{`
-   = note: this error originates in a macro outside of the current crate (run with -Z external-macro-backtrace for more info)
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: invalid format string: unmatched `}` found
   --> $DIR/format-string-error.rs:14:5
@@ -14,7 +14,7 @@ error: invalid format string: unmatched `}` found
    |     ^^^^^^^^^^^^^^
    |
    = note: if you intended to print `}`, you can escape it using `}}`
-   = note: this error originates in a macro outside of the current crate (run with -Z external-macro-backtrace for more info)
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/lifetimes/borrowck-let-suggestion.stderr b/src/test/ui/lifetimes/borrowck-let-suggestion.stderr
index f61595e869d..675974d617c 100644
--- a/src/test/ui/lifetimes/borrowck-let-suggestion.stderr
+++ b/src/test/ui/lifetimes/borrowck-let-suggestion.stderr
@@ -9,7 +9,7 @@ error[E0597]: borrowed value does not live long enough
    | - temporary value needs to live until here
    |
    = note: consider using a `let` binding to increase its lifetime
-   = note: this error originates in a macro outside of the current crate (run with -Z external-macro-backtrace for more info)
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/macros/format-foreign.stderr b/src/test/ui/macros/format-foreign.stderr
index 95f348b8b8b..d0229957b68 100644
--- a/src/test/ui/macros/format-foreign.stderr
+++ b/src/test/ui/macros/format-foreign.stderr
@@ -11,7 +11,7 @@ error: multiple unused formatting arguments
    = help: `%.*3$s` should be written as `{:.2$}`
    = help: `%s` should be written as `{}`
    = note: printf formatting not supported; see the documentation for `std::fmt`
-   = note: this error originates in a macro outside of the current crate (run with -Z external-macro-backtrace for more info)
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: argument never used
   --> $DIR/format-foreign.rs:13:29
diff --git a/src/test/ui/macros/format-unused-lables.stderr b/src/test/ui/macros/format-unused-lables.stderr
index 01d3577a7c9..9efdca12dea 100644
--- a/src/test/ui/macros/format-unused-lables.stderr
+++ b/src/test/ui/macros/format-unused-lables.stderr
@@ -8,7 +8,7 @@ error: multiple unused formatting arguments
    |                      |    unused
    |                      unused
    |
-   = note: this error originates in a macro outside of the current crate (run with -Z external-macro-backtrace for more info)
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: multiple unused formatting arguments
   --> $DIR/format-unused-lables.rs:14:5
@@ -23,7 +23,7 @@ error: multiple unused formatting arguments
 18 | |     );
    | |______^
    |
-   = note: this error originates in a macro outside of the current crate (run with -Z external-macro-backtrace for more info)
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: named argument never used
   --> $DIR/format-unused-lables.rs:20:35
@@ -47,7 +47,7 @@ error: multiple unused formatting arguments
    |
    = help: `$STUFF` should be written as `{STUFF}`
    = note: shell formatting not supported; see the documentation for `std::fmt`
-   = note: this error originates in a macro outside of the current crate (run with -Z external-macro-backtrace for more info)
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: aborting due to 4 previous errors
 
diff --git a/src/test/ui/reachable/expr_again.stderr b/src/test/ui/reachable/expr_again.stderr
index 54b1d47710c..152c96e52b6 100644
--- a/src/test/ui/reachable/expr_again.stderr
+++ b/src/test/ui/reachable/expr_again.stderr
@@ -9,7 +9,7 @@ note: lint level defined here
    |
 13 | #![deny(unreachable_code)]
    |         ^^^^^^^^^^^^^^^^
-   = note: this error originates in a macro outside of the current crate (run with -Z external-macro-backtrace for more info)
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/reachable/expr_block.stderr b/src/test/ui/reachable/expr_block.stderr
index 4c361dc8855..4c08be524f2 100644
--- a/src/test/ui/reachable/expr_block.stderr
+++ b/src/test/ui/reachable/expr_block.stderr
@@ -16,7 +16,7 @@ error: unreachable statement
 36 |         println!("foo");
    |         ^^^^^^^^^^^^^^^^
    |
-   = note: this error originates in a macro outside of the current crate (run with -Z external-macro-backtrace for more info)
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/reachable/expr_if.stderr b/src/test/ui/reachable/expr_if.stderr
index 2b77f5bb3ca..b8f3f494c5c 100644
--- a/src/test/ui/reachable/expr_if.stderr
+++ b/src/test/ui/reachable/expr_if.stderr
@@ -9,7 +9,7 @@ note: lint level defined here
    |
 14 | #![deny(unreachable_code)]
    |         ^^^^^^^^^^^^^^^^
-   = note: this error originates in a macro outside of the current crate (run with -Z external-macro-backtrace for more info)
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/reachable/expr_loop.stderr b/src/test/ui/reachable/expr_loop.stderr
index bcfe2c5bd63..ce4b30c7984 100644
--- a/src/test/ui/reachable/expr_loop.stderr
+++ b/src/test/ui/reachable/expr_loop.stderr
@@ -9,7 +9,7 @@ note: lint level defined here
    |
 14 | #![deny(unreachable_code)]
    |         ^^^^^^^^^^^^^^^^
-   = note: this error originates in a macro outside of the current crate (run with -Z external-macro-backtrace for more info)
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: unreachable statement
   --> $DIR/expr_loop.rs:31:5
@@ -17,7 +17,7 @@ error: unreachable statement
 31 |     println!("I am dead.");
    |     ^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: this error originates in a macro outside of the current crate (run with -Z external-macro-backtrace for more info)
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: unreachable statement
   --> $DIR/expr_loop.rs:41:5
@@ -25,7 +25,7 @@ error: unreachable statement
 41 |     println!("I am dead.");
    |     ^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: this error originates in a macro outside of the current crate (run with -Z external-macro-backtrace for more info)
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/reachable/expr_match.stderr b/src/test/ui/reachable/expr_match.stderr
index 4b44b38895c..499beac644c 100644
--- a/src/test/ui/reachable/expr_match.stderr
+++ b/src/test/ui/reachable/expr_match.stderr
@@ -16,7 +16,7 @@ error: unreachable statement
 25 |     println!("I am dead");
    |     ^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: this error originates in a macro outside of the current crate (run with -Z external-macro-backtrace for more info)
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: unreachable statement
   --> $DIR/expr_match.rs:35:5
@@ -24,7 +24,7 @@ error: unreachable statement
 35 |     println!("I am dead");
    |     ^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: this error originates in a macro outside of the current crate (run with -Z external-macro-backtrace for more info)
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/reachable/expr_while.stderr b/src/test/ui/reachable/expr_while.stderr
index 31e63c324d2..36109826983 100644
--- a/src/test/ui/reachable/expr_while.stderr
+++ b/src/test/ui/reachable/expr_while.stderr
@@ -9,7 +9,7 @@ note: lint level defined here
    |
 14 | #![deny(unreachable_code)]
    |         ^^^^^^^^^^^^^^^^
-   = note: this error originates in a macro outside of the current crate (run with -Z external-macro-backtrace for more info)
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: unreachable statement
   --> $DIR/expr_while.rs:33:9
@@ -17,7 +17,7 @@ error: unreachable statement
 33 |         println!("I am dead.");
    |         ^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: this error originates in a macro outside of the current crate (run with -Z external-macro-backtrace for more info)
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: unreachable statement
   --> $DIR/expr_while.rs:35:5
@@ -25,7 +25,7 @@ error: unreachable statement
 35 |     println!("I am, too.");
    |     ^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: this error originates in a macro outside of the current crate (run with -Z external-macro-backtrace for more info)
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/span/coerce-suggestions.stderr b/src/test/ui/span/coerce-suggestions.stderr
index 73169e86a1c..98ea34fd992 100644
--- a/src/test/ui/span/coerce-suggestions.stderr
+++ b/src/test/ui/span/coerce-suggestions.stderr
@@ -53,7 +53,7 @@ error[E0308]: mismatched types
    = note: expected type `&mut std::string::String`
               found type `std::string::String`
    = help: try with `&mut format!("foo")`
-   = note: this error originates in a macro outside of the current crate (run with -Z external-macro-backtrace for more info)
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: aborting due to 6 previous errors
 
diff --git a/src/test/ui/span/issue-33884.stderr b/src/test/ui/span/issue-33884.stderr
index 22eecb9d882..cf5190bba0c 100644
--- a/src/test/ui/span/issue-33884.stderr
+++ b/src/test/ui/span/issue-33884.stderr
@@ -6,7 +6,7 @@ error[E0308]: mismatched types
    |
    = note: expected type `std::fmt::Arguments<'_>`
               found type `std::string::String`
-   = note: this error originates in a macro outside of the current crate (run with -Z external-macro-backtrace for more info)
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/span/issue-40157.stderr b/src/test/ui/span/issue-40157.stderr
index 0879cb5fac2..be7967ff619 100644
--- a/src/test/ui/span/issue-40157.stderr
+++ b/src/test/ui/span/issue-40157.stderr
@@ -8,7 +8,7 @@ error[E0597]: `foo` does not live long enough
    |      |                                              borrow occurs here
    |      borrowed value needs to live until here
    |
-   = note: this error originates in a macro outside of the current crate (run with -Z external-macro-backtrace for more info)
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/span/slice-borrow.stderr b/src/test/ui/span/slice-borrow.stderr
index d1e5cf62a02..c1b760aed2b 100644
--- a/src/test/ui/span/slice-borrow.stderr
+++ b/src/test/ui/span/slice-borrow.stderr
@@ -9,7 +9,7 @@ error[E0597]: borrowed value does not live long enough
 19 | }
    | - temporary value needs to live until here
    |
-   = note: this error originates in a macro outside of the current crate (run with -Z external-macro-backtrace for more info)
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/type-check/cannot_infer_local_or_vec.stderr b/src/test/ui/type-check/cannot_infer_local_or_vec.stderr
index 923dcd01070..bbbcb9158ae 100644
--- a/src/test/ui/type-check/cannot_infer_local_or_vec.stderr
+++ b/src/test/ui/type-check/cannot_infer_local_or_vec.stderr
@@ -6,7 +6,7 @@ error[E0282]: type annotations needed
    |         |
    |         consider giving `x` a type
    |
-   = note: this error originates in a macro outside of the current crate (run with -Z external-macro-backtrace for more info)
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/type-check/cannot_infer_local_or_vec_in_tuples.stderr b/src/test/ui/type-check/cannot_infer_local_or_vec_in_tuples.stderr
index 24f2cef4a6c..6c47624d6dc 100644
--- a/src/test/ui/type-check/cannot_infer_local_or_vec_in_tuples.stderr
+++ b/src/test/ui/type-check/cannot_infer_local_or_vec_in_tuples.stderr
@@ -6,7 +6,7 @@ error[E0282]: type annotations needed
    |         |
    |         consider giving the pattern a type
    |
-   = note: this error originates in a macro outside of the current crate (run with -Z external-macro-backtrace for more info)
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: aborting due to previous error