Merging upstream version 1.68.2+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

51 files changed, 1900 insertions, 0 deletions

diff --git a/tests/ui/fmt/auxiliary/format-string-proc-macro.rs b/tests/ui/fmt/auxiliary/format-string-proc-macro.rs
new file mode 100644
index 000000000..1b7ef93f4
--- /dev/null
+++ b/tests/ui/fmt/auxiliary/format-string-proc-macro.rs
@@ -0,0 +1,52 @@
+// force-host
+// no-prefer-dynamic
+
+#![crate_type = "proc-macro"]
+
+extern crate proc_macro;
+
+use proc_macro::{Delimiter, Group, Ident, Literal, Punct, Spacing, Span, TokenStream, TokenTree};
+use std::iter::FromIterator;
+
+#[proc_macro]
+pub fn foo_with_input_span(input: TokenStream) -> TokenStream {
+    let span = input.into_iter().next().unwrap().span();
+
+    let mut lit = Literal::string("{foo}");
+    lit.set_span(span);
+
+    TokenStream::from(TokenTree::Literal(lit))
+}
+
+#[proc_macro]
+pub fn err_with_input_span(input: TokenStream) -> TokenStream {
+    let span = input.into_iter().next().unwrap().span();
+
+    let mut lit = Literal::string("         }");
+    lit.set_span(span);
+
+    TokenStream::from(TokenTree::Literal(lit))
+}
+
+
+#[proc_macro]
+pub fn respan_to_invalid_format_literal(input: TokenStream) -> TokenStream {
+    let mut s = Literal::string("{");
+    s.set_span(input.into_iter().next().unwrap().span());
+    TokenStream::from_iter([
+        TokenTree::from(Ident::new("format", Span::call_site())),
+        TokenTree::from(Punct::new('!', Spacing::Alone)),
+        TokenTree::from(Group::new(Delimiter::Parenthesis, TokenTree::from(s).into())),
+    ])
+}
+
+#[proc_macro]
+pub fn capture_a_with_prepended_space_preserve_span(input: TokenStream) -> TokenStream {
+    let mut s = Literal::string(" {a}");
+    s.set_span(input.into_iter().next().unwrap().span());
+    TokenStream::from_iter([
+        TokenTree::from(Ident::new("format", Span::call_site())),
+        TokenTree::from(Punct::new('!', Spacing::Alone)),
+        TokenTree::from(Group::new(Delimiter::Parenthesis, TokenTree::from(s).into())),
+    ])
+}
diff --git a/tests/ui/fmt/format-args-capture-issue-102057.rs b/tests/ui/fmt/format-args-capture-issue-102057.rs
new file mode 100644
index 000000000..b8089d49b
--- /dev/null
+++ b/tests/ui/fmt/format-args-capture-issue-102057.rs
@@ -0,0 +1,19 @@
+fn main() {
+    format!("\x7Ba}");
+    //~^ ERROR cannot find value `a` in this scope
+    format!("\x7Ba\x7D");
+    //~^ ERROR cannot find value `a` in this scope
+
+    let a = 0;
+
+    format!("\x7Ba} {b}");
+    //~^ ERROR cannot find value `b` in this scope
+    format!("\x7Ba\x7D {b}");
+    //~^ ERROR cannot find value `b` in this scope
+    format!("\x7Ba} \x7Bb}");
+    //~^ ERROR cannot find value `b` in this scope
+    format!("\x7Ba\x7D \x7Bb}");
+    //~^ ERROR cannot find value `b` in this scope
+    format!("\x7Ba\x7D \x7Bb\x7D");
+    //~^ ERROR cannot find value `b` in this scope
+}
diff --git a/tests/ui/fmt/format-args-capture-issue-102057.stderr b/tests/ui/fmt/format-args-capture-issue-102057.stderr
new file mode 100644
index 000000000..f2d625e7f
--- /dev/null
+++ b/tests/ui/fmt/format-args-capture-issue-102057.stderr
@@ -0,0 +1,45 @@
+error[E0425]: cannot find value `a` in this scope
+  --> $DIR/format-args-capture-issue-102057.rs:2:18
+   |
+LL |     format!("\x7Ba}");
+   |                  ^ not found in this scope
+
+error[E0425]: cannot find value `a` in this scope
+  --> $DIR/format-args-capture-issue-102057.rs:4:18
+   |
+LL |     format!("\x7Ba\x7D");
+   |                  ^ not found in this scope
+
+error[E0425]: cannot find value `b` in this scope
+  --> $DIR/format-args-capture-issue-102057.rs:9:22
+   |
+LL |     format!("\x7Ba} {b}");
+   |                      ^ help: a local variable with a similar name exists: `a`
+
+error[E0425]: cannot find value `b` in this scope
+  --> $DIR/format-args-capture-issue-102057.rs:11:25
+   |
+LL |     format!("\x7Ba\x7D {b}");
+   |                         ^ help: a local variable with a similar name exists: `a`
+
+error[E0425]: cannot find value `b` in this scope
+  --> $DIR/format-args-capture-issue-102057.rs:13:25
+   |
+LL |     format!("\x7Ba} \x7Bb}");
+   |                         ^ help: a local variable with a similar name exists: `a`
+
+error[E0425]: cannot find value `b` in this scope
+  --> $DIR/format-args-capture-issue-102057.rs:15:28
+   |
+LL |     format!("\x7Ba\x7D \x7Bb}");
+   |                            ^ help: a local variable with a similar name exists: `a`
+
+error[E0425]: cannot find value `b` in this scope
+  --> $DIR/format-args-capture-issue-102057.rs:17:28
+   |
+LL |     format!("\x7Ba\x7D \x7Bb\x7D");
+   |                            ^ help: a local variable with a similar name exists: `a`
+
+error: aborting due to 7 previous errors
+
+For more information about this error, try `rustc --explain E0425`.
diff --git a/tests/ui/fmt/format-args-capture-issue-93378.rs b/tests/ui/fmt/format-args-capture-issue-93378.rs
new file mode 100644
index 000000000..9d722a028
--- /dev/null
+++ b/tests/ui/fmt/format-args-capture-issue-93378.rs
@@ -0,0 +1,11 @@
+fn main() {
+    let a = "a";
+    let b = "b";
+
+    println!("{a} {b} {} {} {c} {}", c = "c");
+    //~^ ERROR: 3 positional arguments in format string, but there is 1 argument
+
+    let n = 1;
+    println!("{a:.n$} {b:.*}");
+    //~^ ERROR: 1 positional argument in format string, but no arguments were given
+}
diff --git a/tests/ui/fmt/format-args-capture-issue-93378.stderr b/tests/ui/fmt/format-args-capture-issue-93378.stderr
new file mode 100644
index 000000000..6429b0d46
--- /dev/null
+++ b/tests/ui/fmt/format-args-capture-issue-93378.stderr
@@ -0,0 +1,17 @@
+error: 3 positional arguments in format string, but there is 1 argument
+  --> $DIR/format-args-capture-issue-93378.rs:5:23
+   |
+LL |     println!("{a} {b} {} {} {c} {}", c = "c");
+   |                       ^^ ^^     ^^       ---
+
+error: 1 positional argument in format string, but no arguments were given
+  --> $DIR/format-args-capture-issue-93378.rs:9:26
+   |
+LL |     println!("{a:.n$} {b:.*}");
+   |                          ^^ this precision flag adds an extra required argument at position 0, which is why there is 1 argument expected
+   |
+   = note: positional arguments are zero-based
+   = note: for information about formatting flags, visit https://doc.rust-lang.org/std/fmt/index.html
+
+error: aborting due to 2 previous errors
+
diff --git a/tests/ui/fmt/format-args-capture-issue-94010.rs b/tests/ui/fmt/format-args-capture-issue-94010.rs
new file mode 100644
index 000000000..bd03e9c93
--- /dev/null
+++ b/tests/ui/fmt/format-args-capture-issue-94010.rs
@@ -0,0 +1,7 @@
+fn main() {
+    const FOO: i32 = 123;
+    println!("{foo:X}");
+    //~^ ERROR: cannot find value `foo` in this scope
+    println!("{:.foo$}", 0);
+    //~^ ERROR: cannot find value `foo` in this scope
+}
diff --git a/tests/ui/fmt/format-args-capture-issue-94010.stderr b/tests/ui/fmt/format-args-capture-issue-94010.stderr
new file mode 100644
index 000000000..ed90dc855
--- /dev/null
+++ b/tests/ui/fmt/format-args-capture-issue-94010.stderr
@@ -0,0 +1,20 @@
+error[E0425]: cannot find value `foo` in this scope
+  --> $DIR/format-args-capture-issue-94010.rs:3:16
+   |
+LL |     const FOO: i32 = 123;
+   |     --------------------- similarly named constant `FOO` defined here
+LL |     println!("{foo:X}");
+   |                ^^^ help: a constant with a similar name exists (notice the capitalization): `FOO`
+
+error[E0425]: cannot find value `foo` in this scope
+  --> $DIR/format-args-capture-issue-94010.rs:5:18
+   |
+LL |     const FOO: i32 = 123;
+   |     --------------------- similarly named constant `FOO` defined here
+...
+LL |     println!("{:.foo$}", 0);
+   |                  ^^^ help: a constant with a similar name exists (notice the capitalization): `FOO`
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0425`.
diff --git a/tests/ui/fmt/format-args-capture-macro-hygiene.rs b/tests/ui/fmt/format-args-capture-macro-hygiene.rs
new file mode 100644
index 000000000..b04f80ba4
--- /dev/null
+++ b/tests/ui/fmt/format-args-capture-macro-hygiene.rs
@@ -0,0 +1,22 @@
+// aux-build:format-string-proc-macro.rs
+
+#[macro_use]
+extern crate format_string_proc_macro;
+
+macro_rules! def_site {
+    () => { "{foo}" } //~ ERROR: there is no argument named `foo`
+}
+
+macro_rules! call_site {
+    ($fmt:literal) => { $fmt }
+}
+
+fn main() {
+    format!(concat!("{foo}"));         //~ ERROR: there is no argument named `foo`
+    format!(concat!("{ba", "r} {}"), 1);     //~ ERROR: there is no argument named `bar`
+
+    format!(def_site!());
+    format!(call_site!("{foo}")); //~ ERROR: there is no argument named `foo`
+
+    format!(foo_with_input_span!("")); //~ ERROR: there is no argument named `foo`
+}
diff --git a/tests/ui/fmt/format-args-capture-macro-hygiene.stderr b/tests/ui/fmt/format-args-capture-macro-hygiene.stderr
new file mode 100644
index 000000000..1b5fbd2af
--- /dev/null
+++ b/tests/ui/fmt/format-args-capture-macro-hygiene.stderr
@@ -0,0 +1,53 @@
+error: there is no argument named `foo`
+  --> $DIR/format-args-capture-macro-hygiene.rs:15:13
+   |
+LL |     format!(concat!("{foo}"));
+   |             ^^^^^^^^^^^^^^^^
+   |
+   = note: did you intend to capture a variable `foo` from the surrounding scope?
+   = note: to avoid ambiguity, `format_args!` cannot capture variables when the format string is expanded from a macro
+   = note: this error originates in the macro `concat` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: there is no argument named `bar`
+  --> $DIR/format-args-capture-macro-hygiene.rs:16:13
+   |
+LL |     format!(concat!("{ba", "r} {}"), 1);
+   |             ^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: did you intend to capture a variable `bar` from the surrounding scope?
+   = note: to avoid ambiguity, `format_args!` cannot capture variables when the format string is expanded from a macro
+   = note: this error originates in the macro `concat` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: there is no argument named `foo`
+  --> $DIR/format-args-capture-macro-hygiene.rs:7:13
+   |
+LL |     () => { "{foo}" }
+   |             ^^^^^^^
+...
+LL |     format!(def_site!());
+   |             ----------- in this macro invocation
+   |
+   = note: did you intend to capture a variable `foo` from the surrounding scope?
+   = note: to avoid ambiguity, `format_args!` cannot capture variables when the format string is expanded from a macro
+   = note: this error originates in the macro `def_site` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: there is no argument named `foo`
+  --> $DIR/format-args-capture-macro-hygiene.rs:19:24
+   |
+LL |     format!(call_site!("{foo}"));
+   |                        ^^^^^^^
+   |
+   = note: did you intend to capture a variable `foo` from the surrounding scope?
+   = note: to avoid ambiguity, `format_args!` cannot capture variables when the format string is expanded from a macro
+
+error: there is no argument named `foo`
+  --> $DIR/format-args-capture-macro-hygiene.rs:21:34
+   |
+LL |     format!(foo_with_input_span!(""));
+   |                                  ^^
+   |
+   = note: did you intend to capture a variable `foo` from the surrounding scope?
+   = note: to avoid ambiguity, `format_args!` cannot capture variables when the format string is expanded from a macro
+
+error: aborting due to 5 previous errors
+
diff --git a/tests/ui/fmt/format-args-capture-missing-variables.rs b/tests/ui/fmt/format-args-capture-missing-variables.rs
new file mode 100644
index 000000000..46fc083cb
--- /dev/null
+++ b/tests/ui/fmt/format-args-capture-missing-variables.rs
@@ -0,0 +1,20 @@
+fn main() {
+    format!("{} {foo} {} {bar} {}", 1, 2, 3);
+    //~^ ERROR: cannot find value `foo` in this scope
+    //~^^ ERROR: cannot find value `bar` in this scope
+
+    format!("{foo}"); //~ ERROR: cannot find value `foo` in this scope
+
+    format!("{valuea} {valueb}", valuea=5, valuec=7);
+    //~^ ERROR cannot find value `valueb` in this scope
+    //~^^ ERROR named argument never used
+
+    format!(r##"
+
+        {foo}
+
+    "##);
+    //~^^^ ERROR: cannot find value `foo` in this scope
+
+    panic!("{foo} {bar}", bar=1); //~ ERROR: cannot find value `foo` in this scope
+}
diff --git a/tests/ui/fmt/format-args-capture-missing-variables.stderr b/tests/ui/fmt/format-args-capture-missing-variables.stderr
new file mode 100644
index 000000000..d980e7be2
--- /dev/null
+++ b/tests/ui/fmt/format-args-capture-missing-variables.stderr
@@ -0,0 +1,47 @@
+error: named argument never used
+  --> $DIR/format-args-capture-missing-variables.rs:8:51
+   |
+LL |     format!("{valuea} {valueb}", valuea=5, valuec=7);
+   |             -------------------                   ^ named argument never used
+   |             |
+   |             formatting specifier missing
+
+error[E0425]: cannot find value `foo` in this scope
+  --> $DIR/format-args-capture-missing-variables.rs:2:18
+   |
+LL |     format!("{} {foo} {} {bar} {}", 1, 2, 3);
+   |                  ^^^ not found in this scope
+
+error[E0425]: cannot find value `bar` in this scope
+  --> $DIR/format-args-capture-missing-variables.rs:2:27
+   |
+LL |     format!("{} {foo} {} {bar} {}", 1, 2, 3);
+   |                           ^^^ not found in this scope
+
+error[E0425]: cannot find value `foo` in this scope
+  --> $DIR/format-args-capture-missing-variables.rs:6:15
+   |
+LL |     format!("{foo}");
+   |               ^^^ not found in this scope
+
+error[E0425]: cannot find value `valueb` in this scope
+  --> $DIR/format-args-capture-missing-variables.rs:8:24
+   |
+LL |     format!("{valuea} {valueb}", valuea=5, valuec=7);
+   |                        ^^^^^^ not found in this scope
+
+error[E0425]: cannot find value `foo` in this scope
+  --> $DIR/format-args-capture-missing-variables.rs:14:10
+   |
+LL |         {foo}
+   |          ^^^ not found in this scope
+
+error[E0425]: cannot find value `foo` in this scope
+  --> $DIR/format-args-capture-missing-variables.rs:19:14
+   |
+LL |     panic!("{foo} {bar}", bar=1);
+   |              ^^^ not found in this scope
+
+error: aborting due to 7 previous errors
+
+For more information about this error, try `rustc --explain E0425`.
diff --git a/tests/ui/fmt/format-args-capture.rs b/tests/ui/fmt/format-args-capture.rs
new file mode 100644
index 000000000..560352b5c
--- /dev/null
+++ b/tests/ui/fmt/format-args-capture.rs
@@ -0,0 +1,89 @@
+// run-pass
+
+fn main() {
+    named_argument_takes_precedence_to_captured();
+    formatting_parameters_can_be_captured();
+    capture_raw_strings_and_idents();
+    repeated_capture();
+
+    #[cfg(panic = "unwind")]
+    {
+        panic_with_single_argument_does_not_get_formatted();
+        panic_with_multiple_arguments_is_formatted();
+    }
+}
+
+fn named_argument_takes_precedence_to_captured() {
+    let foo = "captured";
+    let s = format!("{foo}", foo = "named");
+    assert_eq!(&s, "named");
+
+    let s = format!("{foo}-{foo}-{foo}", foo = "named");
+    assert_eq!(&s, "named-named-named");
+
+    let s = format!("{}-{bar}-{foo}", "positional", bar = "named");
+    assert_eq!(&s, "positional-named-captured");
+}
+
+fn capture_raw_strings_and_idents() {
+    let r#type = "apple";
+    let s = format!(r#"The fruit is an {type}"#);
+    assert_eq!(&s, "The fruit is an apple");
+
+    let r#type = "orange";
+    let s = format!(r"The fruit is an {type}");
+    assert_eq!(&s, "The fruit is an orange");
+}
+
+#[cfg(panic = "unwind")]
+fn panic_with_single_argument_does_not_get_formatted() {
+    // panic! with a single argument does not perform string formatting.
+    // RFC #2795 suggests that this may need to change so that captured arguments are formatted.
+    // For stability reasons this will need to part of an edition change.
+
+    #[allow(non_fmt_panics)]
+    let msg = std::panic::catch_unwind(|| {
+        panic!("{foo}");
+    })
+    .unwrap_err();
+
+    assert_eq!(msg.downcast_ref::<&str>(), Some(&"{foo}"))
+}
+
+#[cfg(panic = "unwind")]
+fn panic_with_multiple_arguments_is_formatted() {
+    let foo = "captured";
+
+    let msg = std::panic::catch_unwind(|| {
+        panic!("{}-{bar}-{foo}", "positional", bar = "named");
+    })
+    .unwrap_err();
+
+    assert_eq!(msg.downcast_ref::<String>(), Some(&"positional-named-captured".to_string()))
+}
+
+fn formatting_parameters_can_be_captured() {
+    let width = 9;
+    let precision = 3;
+
+    let x = 7.0;
+
+    let s = format!("{x:width$}");
+    assert_eq!(&s, "        7");
+
+    let s = format!("{x:<width$}");
+    assert_eq!(&s, "7        ");
+
+    let s = format!("{x:-^width$}");
+    assert_eq!(&s, "----7----");
+
+    let s = format!("{x:-^width$.precision$}");
+    assert_eq!(&s, "--7.000--");
+}
+
+fn repeated_capture() {
+    let a = 1;
+    let b = 2;
+    let s = format!("{a} {b} {a}");
+    assert_eq!(&s, "1 2 1");
+}
diff --git a/tests/ui/fmt/format-expanded-string.rs b/tests/ui/fmt/format-expanded-string.rs
new file mode 100644
index 000000000..4c716f08c
--- /dev/null
+++ b/tests/ui/fmt/format-expanded-string.rs
@@ -0,0 +1,24 @@
+// aux-build:format-string-proc-macro.rs
+
+#[macro_use]
+extern crate format_string_proc_macro;
+
+
+// If the format string is another macro invocation, rustc would previously
+// compute nonsensical spans, such as:
+//
+//   error: invalid format string: unmatched `}` found
+//    --> test.rs:2:17
+//     |
+//   2 |     format!(concat!("abc}"));
+//     |                 ^ unmatched `}` in format string
+//
+// This test checks that this behavior has been fixed.
+
+fn main() {
+    format!(concat!("abc}"));
+    //~^ ERROR: invalid format string: unmatched `}` found
+
+    format!(err_with_input_span!(""));
+    //~^ ERROR: invalid format string: unmatched `}` found
+}
diff --git a/tests/ui/fmt/format-expanded-string.stderr b/tests/ui/fmt/format-expanded-string.stderr
new file mode 100644
index 000000000..26ce7f269
--- /dev/null
+++ b/tests/ui/fmt/format-expanded-string.stderr
@@ -0,0 +1,19 @@
+error: invalid format string: unmatched `}` found
+  --> $DIR/format-expanded-string.rs:19:13
+   |
+LL |     format!(concat!("abc}"));
+   |             ^^^^^^^^^^^^^^^ unmatched `}` in format string
+   |
+   = note: if you intended to print `}`, you can escape it using `}}`
+   = note: this error originates in the macro `concat` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: invalid format string: unmatched `}` found
+  --> $DIR/format-expanded-string.rs:22:34
+   |
+LL |     format!(err_with_input_span!(""));
+   |                                  ^^ unmatched `}` in format string
+   |
+   = note: if you intended to print `}`, you can escape it using `}}`
+
+error: aborting due to 2 previous errors
+
diff --git a/tests/ui/fmt/format-raw-string-error.rs b/tests/ui/fmt/format-raw-string-error.rs
new file mode 100644
index 000000000..9f0bc01a7
--- /dev/null
+++ b/tests/ui/fmt/format-raw-string-error.rs
@@ -0,0 +1,3 @@
+fn main() {
+    println!(r#"\'\'\'\'\'\'\'\'\'\'\'\'\'\'}"#); //~ ERROR invalid format string: unmatched `}` found
+}
diff --git a/tests/ui/fmt/format-raw-string-error.stderr b/tests/ui/fmt/format-raw-string-error.stderr
new file mode 100644
index 000000000..8d61950d8
--- /dev/null
+++ b/tests/ui/fmt/format-raw-string-error.stderr
@@ -0,0 +1,10 @@
+error: invalid format string: unmatched `}` found
+  --> $DIR/format-raw-string-error.rs:2:45
+   |
+LL |     println!(r#"\'\'\'\'\'\'\'\'\'\'\'\'\'\'}"#);
+   |                                             ^ unmatched `}` in format string
+   |
+   = note: if you intended to print `}`, you can escape it using `}}`
+
+error: aborting due to previous error
+
diff --git a/tests/ui/fmt/format-string-error-2.rs b/tests/ui/fmt/format-string-error-2.rs
new file mode 100644
index 000000000..1f7f0d8f6
--- /dev/null
+++ b/tests/ui/fmt/format-string-error-2.rs
@@ -0,0 +1,86 @@
+// ignore-tidy-tab
+
+fn main() {
+    format!("{
+    a");
+    //~^ ERROR invalid format string
+    format!("{ \
+               \
+    b");
+    //~^ ERROR invalid format string
+    format!(r#"{ \
+
+    rawc"#);
+    //~^^^ ERROR invalid format string
+    format!(r#"{ \n
+\n
+    rawd"#);
+    //~^^^ ERROR invalid format string
+    format!("{ \n
+\n
+    e");
+    //~^ ERROR invalid format string
+    format!("
+    {
+    a");
+    //~^ ERROR invalid format string
+    format!("
+    {
+    a
+    ");
+    //~^^ ERROR invalid format string
+    format!("  \
+    { \
+    	\
+    b");
+    //~^ ERROR invalid format string
+    format!("  \
+    { \
+    	\
+    b \
+      \
+    ");
+    //~^^^ ERROR invalid format string
+    format!(r#"
+raw  { \
+       \
+    c"#);
+    //~^^^ ERROR invalid format string
+    format!(r#"
+raw  { \n
+\n
+    d"#);
+    //~^^^ ERROR invalid format string
+    format!("
+  { \n
+\n
+    e");
+    //~^ ERROR invalid format string
+
+    format!("
+    {asdf
+    }
+    ", asdf=1);
+    // ok - this is supported
+    format!("
+    {
+    asdf}
+    ", asdf=1);
+    //~^^ ERROR invalid format string
+    println!("\t{}");
+    //~^ ERROR 1 positional argument in format string
+
+    // note: `\x7B` is `{`
+    println!("\x7B}\u{8} {", 1);
+    //~^ ERROR invalid format string: expected `'}'` but string was terminated
+
+    println!("\x7B}\u8 {", 1);
+    //~^ ERROR incorrect unicode escape sequence
+
+    // note: raw strings don't escape `\xFF` and `\u{FF}` sequences
+    println!(r#"\x7B}\u{8} {"#, 1);
+    //~^ ERROR invalid format string: unmatched `}` found
+
+    println!(r#"\x7B}\u8 {"#, 1);
+    //~^ ERROR invalid format string: unmatched `}` found
+}
diff --git a/tests/ui/fmt/format-string-error-2.stderr b/tests/ui/fmt/format-string-error-2.stderr
new file mode 100644
index 000000000..76cdfbb93
--- /dev/null
+++ b/tests/ui/fmt/format-string-error-2.stderr
@@ -0,0 +1,175 @@
+error: incorrect unicode escape sequence
+  --> $DIR/format-string-error-2.rs:77:20
+   |
+LL |     println!("\x7B}\u8 {", 1);
+   |                    ^^^ help: format of unicode escape sequences uses braces: `\u{8}`
+
+error: invalid format string: expected `'}'`, found `'a'`
+  --> $DIR/format-string-error-2.rs:5:5
+   |
+LL |     format!("{
+   |              - because of this opening brace
+LL |     a");
+   |     ^ expected `}` in format string
+   |
+   = note: if you intended to print `{`, you can escape it using `{{`
+
+error: invalid format string: expected `'}'`, found `'b'`
+  --> $DIR/format-string-error-2.rs:9:5
+   |
+LL |     format!("{ \
+   |              - because of this opening brace
+LL |                \
+LL |     b");
+   |     ^ expected `}` in format string
+   |
+   = note: if you intended to print `{`, you can escape it using `{{`
+
+error: invalid format string: expected `'}'`, found `'\'`
+  --> $DIR/format-string-error-2.rs:11:18
+   |
+LL |     format!(r#"{ \
+   |                - ^ expected `}` in format string
+   |                |
+   |                because of this opening brace
+   |
+   = note: if you intended to print `{`, you can escape it using `{{`
+
+error: invalid format string: expected `'}'`, found `'\'`
+  --> $DIR/format-string-error-2.rs:15:18
+   |
+LL |     format!(r#"{ \n
+   |                - ^ expected `}` in format string
+   |                |
+   |                because of this opening brace
+   |
+   = note: if you intended to print `{`, you can escape it using `{{`
+
+error: invalid format string: expected `'}'`, found `'e'`
+  --> $DIR/format-string-error-2.rs:21:5
+   |
+LL |     format!("{ \n
+   |              - because of this opening brace
+LL | \n
+LL |     e");
+   |     ^ expected `}` in format string
+   |
+   = note: if you intended to print `{`, you can escape it using `{{`
+
+error: invalid format string: expected `'}'`, found `'a'`
+  --> $DIR/format-string-error-2.rs:25:5
+   |
+LL |     {
+   |     - because of this opening brace
+LL |     a");
+   |     ^ expected `}` in format string
+   |
+   = note: if you intended to print `{`, you can escape it using `{{`
+
+error: invalid format string: expected `'}'`, found `'a'`
+  --> $DIR/format-string-error-2.rs:29:5
+   |
+LL |     {
+   |     - because of this opening brace
+LL |     a
+   |     ^ expected `}` in format string
+   |
+   = note: if you intended to print `{`, you can escape it using `{{`
+
+error: invalid format string: expected `'}'`, found `'b'`
+  --> $DIR/format-string-error-2.rs:35:5
+   |
+LL |     { \
+   |     - because of this opening brace
+LL |         \
+LL |     b");
+   |     ^ expected `}` in format string
+   |
+   = note: if you intended to print `{`, you can escape it using `{{`
+
+error: invalid format string: expected `'}'`, found `'b'`
+  --> $DIR/format-string-error-2.rs:40:5
+   |
+LL |     { \
+   |     - because of this opening brace
+LL |         \
+LL |     b \
+   |     ^ expected `}` in format string
+   |
+   = note: if you intended to print `{`, you can escape it using `{{`
+
+error: invalid format string: expected `'}'`, found `'\'`
+  --> $DIR/format-string-error-2.rs:45:8
+   |
+LL | raw  { \
+   |      - ^ expected `}` in format string
+   |      |
+   |      because of this opening brace
+   |
+   = note: if you intended to print `{`, you can escape it using `{{`
+
+error: invalid format string: expected `'}'`, found `'\'`
+  --> $DIR/format-string-error-2.rs:50:8
+   |
+LL | raw  { \n
+   |      - ^ expected `}` in format string
+   |      |
+   |      because of this opening brace
+   |
+   = note: if you intended to print `{`, you can escape it using `{{`
+
+error: invalid format string: expected `'}'`, found `'e'`
+  --> $DIR/format-string-error-2.rs:57:5
+   |
+LL |   { \n
+   |   - because of this opening brace
+LL | \n
+LL |     e");
+   |     ^ expected `}` in format string
+   |
+   = note: if you intended to print `{`, you can escape it using `{{`
+
+error: invalid format string: expected `'}'`, found `'a'`
+  --> $DIR/format-string-error-2.rs:67:5
+   |
+LL |     {
+   |     - because of this opening brace
+LL |     asdf}
+   |     ^ expected `}` in format string
+   |
+   = note: if you intended to print `{`, you can escape it using `{{`
+
+error: 1 positional argument in format string, but no arguments were given
+  --> $DIR/format-string-error-2.rs:70:17
+   |
+LL |     println!("\t{}");
+   |                 ^^
+
+error: invalid format string: expected `'}'` but string was terminated
+  --> $DIR/format-string-error-2.rs:74:27
+   |
+LL |     println!("\x7B}\u{8} {", 1);
+   |                          -^ expected `'}'` in format string
+   |                          |
+   |                          because of this opening brace
+   |
+   = note: if you intended to print `{`, you can escape it using `{{`
+
+error: invalid format string: unmatched `}` found
+  --> $DIR/format-string-error-2.rs:81:21
+   |
+LL |     println!(r#"\x7B}\u{8} {"#, 1);
+   |                     ^ unmatched `}` in format string
+   |
+   = note: if you intended to print `}`, you can escape it using `}}`
+
+error: invalid format string: unmatched `}` found
+  --> $DIR/format-string-error-2.rs:84:21
+   |
+LL |     println!(r#"\x7B}\u8 {"#, 1);
+   |                     ^ unmatched `}` in format string
+   |
+   = note: if you intended to print `}`, you can escape it using `}}`
+
+error: aborting due to 18 previous errors
+
diff --git a/tests/ui/fmt/format-string-error.rs b/tests/ui/fmt/format-string-error.rs
new file mode 100644
index 000000000..eae4f3cb5
--- /dev/null
+++ b/tests/ui/fmt/format-string-error.rs
@@ -0,0 +1,55 @@
+// ignore-tidy-tab
+
+fn main() {
+    println!("{");
+    //~^ ERROR invalid format string: expected `'}'` but string was terminated
+    println!("{{}}");
+    println!("}");
+    //~^ ERROR invalid format string: unmatched `}` found
+    let _ = format!("{_}", _ = 6usize);
+    //~^ ERROR invalid format string: invalid argument name `_`
+    let _ = format!("{a:_}", a = "", _ = 0);
+    //~^ ERROR invalid format string: invalid argument name `_`
+    let _ = format!("{a:._$}", a = "", _ = 0);
+    //~^ ERROR invalid format string: invalid argument name `_`
+    let _ = format!("{");
+    //~^ ERROR invalid format string: expected `'}'` but string was terminated
+    let _ = format!("}");
+    //~^ ERROR invalid format string: unmatched `}` found
+    let _ = format!("{\\}");
+    //~^ ERROR invalid format string: expected `'}'`, found `'\\'`
+    let _ = format!("\n\n\n{\n\n\n");
+    //~^ ERROR invalid format string
+    let _ = format!(r###"
+
+
+
+	{"###);
+    //~^ ERROR invalid format string
+    let _ = format!(r###"
+
+
+
+	{
+
+"###);
+    //~^ ERROR invalid format string
+    let _ = format!(r###"
+
+
+
+	}
+
+"###);
+    //~^^^ ERROR invalid format string
+    let _ = format!(r###"
+
+
+
+        }
+
+"###);
+    //~^^^ ERROR invalid format string: unmatched `}` found
+    println!("{} {} {}", 1, 2);
+    //~^ ERROR 3 positional arguments in format string, but there are 2 arguments
+}
diff --git a/tests/ui/fmt/format-string-error.stderr b/tests/ui/fmt/format-string-error.stderr
new file mode 100644
index 000000000..8a32c2254
--- /dev/null
+++ b/tests/ui/fmt/format-string-error.stderr
@@ -0,0 +1,125 @@
+error: invalid format string: expected `'}'` but string was terminated
+  --> $DIR/format-string-error.rs:4:16
+   |
+LL |     println!("{");
+   |               -^ expected `'}'` in format string
+   |               |
+   |               because of this opening brace
+   |
+   = note: if you intended to print `{`, you can escape it using `{{`
+
+error: invalid format string: unmatched `}` found
+  --> $DIR/format-string-error.rs:7:15
+   |
+LL |     println!("}");
+   |               ^ unmatched `}` in format string
+   |
+   = note: if you intended to print `}`, you can escape it using `}}`
+
+error: invalid format string: invalid argument name `_`
+  --> $DIR/format-string-error.rs:9:23
+   |
+LL |     let _ = format!("{_}", _ = 6usize);
+   |                       ^ invalid argument name in format string
+   |
+   = note: argument name cannot be a single underscore
+
+error: invalid format string: invalid argument name `_`
+  --> $DIR/format-string-error.rs:11:25
+   |
+LL |     let _ = format!("{a:_}", a = "", _ = 0);
+   |                         ^ invalid argument name in format string
+   |
+   = note: argument name cannot be a single underscore
+
+error: invalid format string: invalid argument name `_`
+  --> $DIR/format-string-error.rs:13:26
+   |
+LL |     let _ = format!("{a:._$}", a = "", _ = 0);
+   |                          ^ invalid argument name in format string
+   |
+   = note: argument name cannot be a single underscore
+
+error: invalid format string: expected `'}'` but string was terminated
+  --> $DIR/format-string-error.rs:15:23
+   |
+LL |     let _ = format!("{");
+   |                      -^ expected `'}'` in format string
+   |                      |
+   |                      because of this opening brace
+   |
+   = note: if you intended to print `{`, you can escape it using `{{`
+
+error: invalid format string: unmatched `}` found
+  --> $DIR/format-string-error.rs:17:22
+   |
+LL |     let _ = format!("}");
+   |                      ^ unmatched `}` in format string
+   |
+   = note: if you intended to print `}`, you can escape it using `}}`
+
+error: invalid format string: expected `'}'`, found `'\'`
+  --> $DIR/format-string-error.rs:19:23
+   |
+LL |     let _ = format!("{\}");
+   |                      -^ expected `}` in format string
+   |                      |
+   |                      because of this opening brace
+   |
+   = note: if you intended to print `{`, you can escape it using `{{`
+
+error: invalid format string: expected `'}'` but string was terminated
+  --> $DIR/format-string-error.rs:21:35
+   |
+LL |     let _ = format!("\n\n\n{\n\n\n");
+   |                            -      ^ expected `'}'` in format string
+   |                            |
+   |                            because of this opening brace
+   |
+   = note: if you intended to print `{`, you can escape it using `{{`
+
+error: invalid format string: expected `'}'` but string was terminated
+  --> $DIR/format-string-error.rs:27:3
+   |
+LL |     {"###);
+   |     -^ expected `'}'` in format string
+   |     |
+   |     because of this opening brace
+   |
+   = note: if you intended to print `{`, you can escape it using `{{`
+
+error: invalid format string: expected `'}'` but string was terminated
+  --> $DIR/format-string-error.rs:35:1
+   |
+LL |     {
+   |     - because of this opening brace
+LL |
+LL | "###);
+   | ^ expected `'}'` in format string
+   |
+   = note: if you intended to print `{`, you can escape it using `{{`
+
+error: invalid format string: unmatched `}` found
+  --> $DIR/format-string-error.rs:41:2
+   |
+LL |     }
+   |     ^ unmatched `}` in format string
+   |
+   = note: if you intended to print `}`, you can escape it using `}}`
+
+error: invalid format string: unmatched `}` found
+  --> $DIR/format-string-error.rs:49:9
+   |
+LL |         }
+   |         ^ unmatched `}` in format string
+   |
+   = note: if you intended to print `}`, you can escape it using `}}`
+
+error: 3 positional arguments in format string, but there are 2 arguments
+  --> $DIR/format-string-error.rs:53:15
+   |
+LL |     println!("{} {} {}", 1, 2);
+   |               ^^ ^^ ^^   -  -
+
+error: aborting due to 14 previous errors
+
diff --git a/tests/ui/fmt/format-with-yield-point.rs b/tests/ui/fmt/format-with-yield-point.rs
new file mode 100644
index 000000000..e484074cc
--- /dev/null
+++ b/tests/ui/fmt/format-with-yield-point.rs
@@ -0,0 +1,33 @@
+// check-pass
+// edition:2021
+
+macro_rules! m {
+    () => {
+        async {}.await
+    };
+}
+
+async fn with_await() {
+    println!("{} {:?}", "", async {}.await);
+}
+
+async fn with_macro_call_expr() {
+    println!("{} {:?}", "", m!());
+}
+
+async fn with_macro_call_stmt_semi() {
+    println!("{} {:?}", "", { m!(); });
+}
+
+async fn with_macro_call_stmt_braced() {
+    println!("{} {:?}", "", { m!{} });
+}
+
+fn assert_send(_: impl Send) {}
+
+fn main() {
+    assert_send(with_await());
+    assert_send(with_macro_call_expr());
+    assert_send(with_macro_call_stmt_semi());
+    assert_send(with_macro_call_stmt_braced());
+}
diff --git a/tests/ui/fmt/ifmt-bad-arg.rs b/tests/ui/fmt/ifmt-bad-arg.rs
new file mode 100644
index 000000000..68861d7bf
--- /dev/null
+++ b/tests/ui/fmt/ifmt-bad-arg.rs
@@ -0,0 +1,99 @@
+fn main() {
+    // bad arguments to the format! call
+
+    // bad number of arguments, see #44954 (originally #15780)
+
+    format!("{}");
+    //~^ ERROR: 1 positional argument in format string, but no arguments were given
+
+    format!("{1}", 1);
+    //~^ ERROR: invalid reference to positional argument 1 (there is 1 argument)
+    //~^^ ERROR: argument never used
+
+    format!("{} {}");
+    //~^ ERROR: 2 positional arguments in format string, but no arguments were given
+
+    format!("{0} {1}", 1);
+    //~^ ERROR: invalid reference to positional argument 1 (there is 1 argument)
+
+    format!("{0} {1} {2}", 1, 2);
+    //~^ ERROR: invalid reference to positional argument 2 (there are 2 arguments)
+
+    format!("{} {value} {} {}", 1, value=2);
+    //~^ ERROR: 3 positional arguments in format string, but there are 2 arguments
+    format!("{name} {value} {} {} {} {} {} {}", 0, name=1, value=2);
+    //~^ ERROR: 6 positional arguments in format string, but there are 3 arguments
+
+    format!("{} {foo} {} {bar} {}", 1, 2, 3);
+    //~^ ERROR: cannot find value `foo` in this scope
+    //~^^ ERROR: cannot find value `bar` in this scope
+
+    format!("{foo}");                //~ ERROR: cannot find value `foo` in this scope
+    format!("", 1, 2);               //~ ERROR: multiple unused formatting arguments
+    format!("{}", 1, 2);             //~ ERROR: argument never used
+    format!("{1}", 1, 2);            //~ ERROR: argument never used
+    format!("{}", 1, foo=2);         //~ ERROR: named argument never used
+    format!("{foo}", 1, foo=2);      //~ ERROR: argument never used
+    format!("", foo=2);              //~ ERROR: named argument never used
+    format!("{} {}", 1, 2, foo=1, bar=2);  //~ ERROR: multiple unused formatting arguments
+
+    format!("{foo}", foo=1, foo=2);  //~ ERROR: duplicate argument
+    format!("{foo} {} {}", foo=1, 2);   //~ ERROR: positional arguments cannot follow
+
+    // bad named arguments, #35082
+
+    format!("{valuea} {valueb}", valuea=5, valuec=7);
+    //~^ ERROR cannot find value `valueb` in this scope
+    //~^^ ERROR named argument never used
+
+    // bad syntax of the format string
+
+    format!("{"); //~ ERROR: expected `'}'` but string was terminated
+
+    format!("foo } bar"); //~ ERROR: unmatched `}` found
+    format!("foo }"); //~ ERROR: unmatched `}` found
+
+    format!("foo %s baz", "bar"); //~ ERROR: argument never used
+
+    format!(r##"
+
+        {foo}
+
+    "##);
+    //~^^^ ERROR: cannot find value `foo` in this scope
+
+    // bad syntax in format string with multiple newlines, #53836
+    format!("first number: {}
+second number: {}
+third number: {}
+fourth number: {}
+fifth number: {}
+sixth number: {}
+seventh number: {}
+eighth number: {}
+ninth number: {
+tenth number: {}",
+        1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
+    //~^^ ERROR: invalid format string
+    println!("{} {:.*} {}", 1, 3.2, 4);
+    //~^ ERROR 4 positional arguments in format string, but there are 3 arguments
+    //~| ERROR mismatched types
+    println!("{} {:07$.*} {}", 1, 3.2, 4);
+    //~^ ERROR invalid reference to positional arguments 3 and 7 (there are 3 arguments)
+    //~| ERROR mismatched types
+    println!("{} {:07$} {}", 1, 3.2, 4);
+    //~^ ERROR invalid reference to positional argument 7 (there are 3 arguments)
+    println!("{:foo}", 1); //~ ERROR unknown format trait `foo`
+    println!("{5} {:4$} {6:7$}", 1);
+    //~^ ERROR invalid reference to positional arguments 4, 5, 6 and 7 (there is 1 argument)
+    let foo = 1;
+    println!("{foo:0$}");
+    //~^ ERROR invalid reference to positional argument 0 (no arguments were given)
+
+    // We used to ICE here because we tried to unconditionally access the first argument, which
+    // doesn't exist.
+    println!("{:.*}");
+    //~^ ERROR 2 positional arguments in format string, but no arguments were given
+    println!("{:.0$}");
+    //~^ ERROR invalid reference to positional argument 0 (no arguments were given)
+}
diff --git a/tests/ui/fmt/ifmt-bad-arg.stderr b/tests/ui/fmt/ifmt-bad-arg.stderr
new file mode 100644
index 000000000..c2619d6df
--- /dev/null
+++ b/tests/ui/fmt/ifmt-bad-arg.stderr
@@ -0,0 +1,332 @@
+error: 1 positional argument in format string, but no arguments were given
+  --> $DIR/ifmt-bad-arg.rs:6:14
+   |
+LL |     format!("{}");
+   |              ^^
+
+error: invalid reference to positional argument 1 (there is 1 argument)
+  --> $DIR/ifmt-bad-arg.rs:9:15
+   |
+LL |     format!("{1}", 1);
+   |               ^
+   |
+   = note: positional arguments are zero-based
+
+error: argument never used
+  --> $DIR/ifmt-bad-arg.rs:9:20
+   |
+LL |     format!("{1}", 1);
+   |             -----  ^ argument never used
+   |             |
+   |             formatting specifier missing
+
+error: 2 positional arguments in format string, but no arguments were given
+  --> $DIR/ifmt-bad-arg.rs:13:14
+   |
+LL |     format!("{} {}");
+   |              ^^ ^^
+
+error: invalid reference to positional argument 1 (there is 1 argument)
+  --> $DIR/ifmt-bad-arg.rs:16:19
+   |
+LL |     format!("{0} {1}", 1);
+   |                   ^
+   |
+   = note: positional arguments are zero-based
+
+error: invalid reference to positional argument 2 (there are 2 arguments)
+  --> $DIR/ifmt-bad-arg.rs:19:23
+   |
+LL |     format!("{0} {1} {2}", 1, 2);
+   |                       ^
+   |
+   = note: positional arguments are zero-based
+
+error: 3 positional arguments in format string, but there are 2 arguments
+  --> $DIR/ifmt-bad-arg.rs:22:14
+   |
+LL |     format!("{} {value} {} {}", 1, value=2);
+   |              ^^         ^^ ^^   -        -
+
+error: 6 positional arguments in format string, but there are 3 arguments
+  --> $DIR/ifmt-bad-arg.rs:24:29
+   |
+LL |     format!("{name} {value} {} {} {} {} {} {}", 0, name=1, value=2);
+   |                             ^^ ^^ ^^ ^^ ^^ ^^   -       -        -
+
+error: multiple unused formatting arguments
+  --> $DIR/ifmt-bad-arg.rs:32:17
+   |
+LL |     format!("", 1, 2);
+   |             --  ^  ^ argument never used
+   |             |   |
+   |             |   argument never used
+   |             multiple missing formatting specifiers
+
+error: argument never used
+  --> $DIR/ifmt-bad-arg.rs:33:22
+   |
+LL |     format!("{}", 1, 2);
+   |             ----     ^ argument never used
+   |             |
+   |             formatting specifier missing
+
+error: argument never used
+  --> $DIR/ifmt-bad-arg.rs:34:20
+   |
+LL |     format!("{1}", 1, 2);
+   |             -----  ^ argument never used
+   |             |
+   |             formatting specifier missing
+
+error: named argument never used
+  --> $DIR/ifmt-bad-arg.rs:35:26
+   |
+LL |     format!("{}", 1, foo=2);
+   |             ----         ^ named argument never used
+   |             |
+   |             formatting specifier missing
+
+error: argument never used
+  --> $DIR/ifmt-bad-arg.rs:36:22
+   |
+LL |     format!("{foo}", 1, foo=2);
+   |             -------  ^ argument never used
+   |             |
+   |             formatting specifier missing
+
+error: named argument never used
+  --> $DIR/ifmt-bad-arg.rs:37:21
+   |
+LL |     format!("", foo=2);
+   |             --      ^ named argument never used
+   |             |
+   |             formatting specifier missing
+
+error: multiple unused formatting arguments
+  --> $DIR/ifmt-bad-arg.rs:38:32
+   |
+LL |     format!("{} {}", 1, 2, foo=1, bar=2);
+   |             -------            ^      ^ named argument never used
+   |             |                  |
+   |             |                  named argument never used
+   |             multiple missing formatting specifiers
+
+error: duplicate argument named `foo`
+  --> $DIR/ifmt-bad-arg.rs:40:29
+   |
+LL |     format!("{foo}", foo=1, foo=2);
+   |                      ---    ^^^ duplicate argument
+   |                      |
+   |                      previously here
+
+error: positional arguments cannot follow named arguments
+  --> $DIR/ifmt-bad-arg.rs:41:35
+   |
+LL |     format!("{foo} {} {}", foo=1, 2);
+   |                            -----  ^ positional arguments must be before named arguments
+   |                            |
+   |                            named argument
+
+error: named argument never used
+  --> $DIR/ifmt-bad-arg.rs:45:51
+   |
+LL |     format!("{valuea} {valueb}", valuea=5, valuec=7);
+   |             -------------------                   ^ named argument never used
+   |             |
+   |             formatting specifier missing
+
+error: invalid format string: expected `'}'` but string was terminated
+  --> $DIR/ifmt-bad-arg.rs:51:15
+   |
+LL |     format!("{");
+   |              -^ expected `'}'` in format string
+   |              |
+   |              because of this opening brace
+   |
+   = note: if you intended to print `{`, you can escape it using `{{`
+
+error: invalid format string: unmatched `}` found
+  --> $DIR/ifmt-bad-arg.rs:53:18
+   |
+LL |     format!("foo } bar");
+   |                  ^ unmatched `}` in format string
+   |
+   = note: if you intended to print `}`, you can escape it using `}}`
+
+error: invalid format string: unmatched `}` found
+  --> $DIR/ifmt-bad-arg.rs:54:18
+   |
+LL |     format!("foo }");
+   |                  ^ unmatched `}` in format string
+   |
+   = note: if you intended to print `}`, you can escape it using `}}`
+
+error: argument never used
+  --> $DIR/ifmt-bad-arg.rs:56:27
+   |
+LL |     format!("foo %s baz", "bar");
+   |                  --       ^^^^^ argument never used
+   |                  |
+   |                  help: format specifiers use curly braces: `{}`
+   |
+   = note: printf formatting is not supported; see the documentation for `std::fmt`
+
+error: invalid format string: expected `'}'`, found `'t'`
+  --> $DIR/ifmt-bad-arg.rs:75:1
+   |
+LL | ninth number: {
+   |               - because of this opening brace
+LL | tenth number: {}",
+   | ^ expected `}` in format string
+   |
+   = note: if you intended to print `{`, you can escape it using `{{`
+
+error: 4 positional arguments in format string, but there are 3 arguments
+  --> $DIR/ifmt-bad-arg.rs:78:15
+   |
+LL |     println!("{} {:.*} {}", 1, 3.2, 4);
+   |               ^^ ^^--^ ^^   -  ---  -
+   |                    |
+   |                    this precision flag adds an extra required argument at position 1, which is why there are 4 arguments expected
+   |
+   = note: positional arguments are zero-based
+   = note: for information about formatting flags, visit https://doc.rust-lang.org/std/fmt/index.html
+
+error: invalid reference to positional arguments 3 and 7 (there are 3 arguments)
+  --> $DIR/ifmt-bad-arg.rs:81:21
+   |
+LL |     println!("{} {:07$.*} {}", 1, 3.2, 4);
+   |                     ^^     ^
+   |
+   = note: positional arguments are zero-based
+   = note: for information about formatting flags, visit https://doc.rust-lang.org/std/fmt/index.html
+
+error: invalid reference to positional argument 7 (there are 3 arguments)
+  --> $DIR/ifmt-bad-arg.rs:84:21
+   |
+LL |     println!("{} {:07$} {}", 1, 3.2, 4);
+   |                     ^^
+   |
+   = note: positional arguments are zero-based
+   = note: for information about formatting flags, visit https://doc.rust-lang.org/std/fmt/index.html
+
+error: unknown format trait `foo`
+  --> $DIR/ifmt-bad-arg.rs:86:17
+   |
+LL |     println!("{:foo}", 1);
+   |                 ^^^
+   |
+   = note: the only appropriate formatting traits are:
+           - ``, which uses the `Display` trait
+           - `?`, which uses the `Debug` trait
+           - `e`, which uses the `LowerExp` trait
+           - `E`, which uses the `UpperExp` trait
+           - `o`, which uses the `Octal` trait
+           - `p`, which uses the `Pointer` trait
+           - `b`, which uses the `Binary` trait
+           - `x`, which uses the `LowerHex` trait
+           - `X`, which uses the `UpperHex` trait
+
+error: invalid reference to positional arguments 4, 5, 6 and 7 (there is 1 argument)
+  --> $DIR/ifmt-bad-arg.rs:87:16
+   |
+LL |     println!("{5} {:4$} {6:7$}", 1);
+   |                ^    ^^   ^ ^^
+   |
+   = note: positional arguments are zero-based
+   = note: for information about formatting flags, visit https://doc.rust-lang.org/std/fmt/index.html
+
+error: invalid reference to positional argument 0 (no arguments were given)
+  --> $DIR/ifmt-bad-arg.rs:90:20
+   |
+LL |     println!("{foo:0$}");
+   |                    ^^
+   |
+   = note: positional arguments are zero-based
+   = note: for information about formatting flags, visit https://doc.rust-lang.org/std/fmt/index.html
+
+error: 2 positional arguments in format string, but no arguments were given
+  --> $DIR/ifmt-bad-arg.rs:95:15
+   |
+LL |     println!("{:.*}");
+   |               ^^--^
+   |                 |
+   |                 this precision flag adds an extra required argument at position 0, which is why there are 2 arguments expected
+   |
+   = note: positional arguments are zero-based
+   = note: for information about formatting flags, visit https://doc.rust-lang.org/std/fmt/index.html
+
+error: invalid reference to positional argument 0 (no arguments were given)
+  --> $DIR/ifmt-bad-arg.rs:97:16
+   |
+LL |     println!("{:.0$}");
+   |                ^^^^
+   |
+   = note: positional arguments are zero-based
+   = note: for information about formatting flags, visit https://doc.rust-lang.org/std/fmt/index.html
+
+error[E0425]: cannot find value `foo` in this scope
+  --> $DIR/ifmt-bad-arg.rs:27:18
+   |
+LL |     format!("{} {foo} {} {bar} {}", 1, 2, 3);
+   |                  ^^^ not found in this scope
+
+error[E0425]: cannot find value `bar` in this scope
+  --> $DIR/ifmt-bad-arg.rs:27:27
+   |
+LL |     format!("{} {foo} {} {bar} {}", 1, 2, 3);
+   |                           ^^^ not found in this scope
+
+error[E0425]: cannot find value `foo` in this scope
+  --> $DIR/ifmt-bad-arg.rs:31:15
+   |
+LL |     format!("{foo}");
+   |               ^^^ not found in this scope
+
+error[E0425]: cannot find value `valueb` in this scope
+  --> $DIR/ifmt-bad-arg.rs:45:24
+   |
+LL |     format!("{valuea} {valueb}", valuea=5, valuec=7);
+   |                        ^^^^^^ not found in this scope
+
+error[E0425]: cannot find value `foo` in this scope
+  --> $DIR/ifmt-bad-arg.rs:60:10
+   |
+LL |         {foo}
+   |          ^^^ not found in this scope
+
+error[E0308]: mismatched types
+  --> $DIR/ifmt-bad-arg.rs:78:32
+   |
+LL |     println!("{} {:.*} {}", 1, 3.2, 4);
+   |                                ^^^
+   |                                |
+   |                                expected `usize`, found floating-point number
+   |                                arguments to this function are incorrect
+   |
+   = note: expected reference `&usize`
+              found reference `&{float}`
+note: associated function defined here
+  --> $SRC_DIR/core/src/fmt/mod.rs:LL:COL
+   = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error[E0308]: mismatched types
+  --> $DIR/ifmt-bad-arg.rs:81:35
+   |
+LL |     println!("{} {:07$.*} {}", 1, 3.2, 4);
+   |                                   ^^^
+   |                                   |
+   |                                   expected `usize`, found floating-point number
+   |                                   arguments to this function are incorrect
+   |
+   = note: expected reference `&usize`
+              found reference `&{float}`
+note: associated function defined here
+  --> $SRC_DIR/core/src/fmt/mod.rs:LL:COL
+   = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to 38 previous errors
+
+Some errors have detailed explanations: E0308, E0425.
+For more information about an error, try `rustc --explain E0308`.
diff --git a/tests/ui/fmt/ifmt-bad-format-args.rs b/tests/ui/fmt/ifmt-bad-format-args.rs
new file mode 100644
index 000000000..ba7301561
--- /dev/null
+++ b/tests/ui/fmt/ifmt-bad-format-args.rs
@@ -0,0 +1,4 @@
+fn main() {
+    format_args!(); //~ ERROR: requires at least a format string argument
+    format_args!(|| {}); //~ ERROR: must be a string literal
+}
diff --git a/tests/ui/fmt/ifmt-bad-format-args.stderr b/tests/ui/fmt/ifmt-bad-format-args.stderr
new file mode 100644
index 000000000..2db280c5e
--- /dev/null
+++ b/tests/ui/fmt/ifmt-bad-format-args.stderr
@@ -0,0 +1,21 @@
+error: requires at least a format string argument
+  --> $DIR/ifmt-bad-format-args.rs:2:5
+   |
+LL |     format_args!();
+   |     ^^^^^^^^^^^^^^
+   |
+   = note: this error originates in the macro `format_args` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: format argument must be a string literal
+  --> $DIR/ifmt-bad-format-args.rs:3:18
+   |
+LL |     format_args!(|| {});
+   |                  ^^^^^
+   |
+help: you might be missing a string literal to format with
+   |
+LL |     format_args!("{}", || {});
+   |                  +++++
+
+error: aborting due to 2 previous errors
+
diff --git a/tests/ui/fmt/ifmt-unimpl.rs b/tests/ui/fmt/ifmt-unimpl.rs
new file mode 100644
index 000000000..258f4eea5
--- /dev/null
+++ b/tests/ui/fmt/ifmt-unimpl.rs
@@ -0,0 +1,4 @@
+fn main() {
+    format!("{:X}", "3");
+    //~^ ERROR: `str: UpperHex` is not satisfied
+}
diff --git a/tests/ui/fmt/ifmt-unimpl.stderr b/tests/ui/fmt/ifmt-unimpl.stderr
new file mode 100644
index 000000000..be321c3c5
--- /dev/null
+++ b/tests/ui/fmt/ifmt-unimpl.stderr
@@ -0,0 +1,24 @@
+error[E0277]: the trait bound `str: UpperHex` is not satisfied
+  --> $DIR/ifmt-unimpl.rs:2:21
+   |
+LL |     format!("{:X}", "3");
+   |                     ^^^ the trait `UpperHex` is not implemented for `str`
+   |
+   = help: the following other types implement trait `UpperHex`:
+             &T
+             &mut T
+             NonZeroI128
+             NonZeroI16
+             NonZeroI32
+             NonZeroI64
+             NonZeroI8
+             NonZeroIsize
+           and 21 others
+   = note: required for `&str` to implement `UpperHex`
+note: required by a bound in `ArgumentV1::<'a>::new_upper_hex`
+  --> $SRC_DIR/core/src/fmt/mod.rs:LL:COL
+   = note: this error originates in the macro `$crate::__export::format_args` which comes from the expansion of the macro `arg_new` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/fmt/ifmt-unknown-trait.rs b/tests/ui/fmt/ifmt-unknown-trait.rs
new file mode 100644
index 000000000..158152c89
--- /dev/null
+++ b/tests/ui/fmt/ifmt-unknown-trait.rs
@@ -0,0 +1,4 @@
+fn main() {
+    format!("{:notimplemented}", "3");
+    //~^ ERROR: unknown format trait `notimplemented`
+}
diff --git a/tests/ui/fmt/ifmt-unknown-trait.stderr b/tests/ui/fmt/ifmt-unknown-trait.stderr
new file mode 100644
index 000000000..459432bf4
--- /dev/null
+++ b/tests/ui/fmt/ifmt-unknown-trait.stderr
@@ -0,0 +1,19 @@
+error: unknown format trait `notimplemented`
+  --> $DIR/ifmt-unknown-trait.rs:2:16
+   |
+LL |     format!("{:notimplemented}", "3");
+   |                ^^^^^^^^^^^^^^
+   |
+   = note: the only appropriate formatting traits are:
+           - ``, which uses the `Display` trait
+           - `?`, which uses the `Debug` trait
+           - `e`, which uses the `LowerExp` trait
+           - `E`, which uses the `UpperExp` trait
+           - `o`, which uses the `Octal` trait
+           - `p`, which uses the `Pointer` trait
+           - `b`, which uses the `Binary` trait
+           - `x`, which uses the `LowerHex` trait
+           - `X`, which uses the `UpperHex` trait
+
+error: aborting due to previous error
+
diff --git a/tests/ui/fmt/incorrect-separator.rs b/tests/ui/fmt/incorrect-separator.rs
new file mode 100644
index 000000000..b8d2e4a34
--- /dev/null
+++ b/tests/ui/fmt/incorrect-separator.rs
@@ -0,0 +1,29 @@
+// Allows to track issue #75492:
+// https://github.com/rust-lang/rust/issues/75492
+
+use std::iter;
+
+fn main() {
+    format!("A number: {}". iter::once(42).next().unwrap());
+    //~^ ERROR expected `,`, found `.`
+
+    // Other kind of types are also checked:
+
+    format!("A number: {}" / iter::once(42).next().unwrap());
+    //~^ ERROR expected `,`, found `/`
+
+    format!("A number: {}"; iter::once(42).next().unwrap());
+    //~^ ERROR expected `,`, found `;`
+
+    // Note: this character is an COMBINING COMMA BELOW unicode char
+    format!("A number: {}" ̦ iter::once(42).next().unwrap());
+    //~^ ERROR expected `,`, found `iter`
+    //~^^ ERROR unknown start of token: \u{326}
+
+    // Here recovery is tested.
+    // If the `compile_error!` is emitted, then the parser is able to recover
+    // from the incorrect first separator.
+    format!("{}". compile_error!("fail"));
+    //~^ ERROR expected `,`, found `.`
+    //~^^ ERROR fail
+}
diff --git a/tests/ui/fmt/incorrect-separator.stderr b/tests/ui/fmt/incorrect-separator.stderr
new file mode 100644
index 000000000..5a3e5515b
--- /dev/null
+++ b/tests/ui/fmt/incorrect-separator.stderr
@@ -0,0 +1,44 @@
+error: unknown start of token: \u{326}
+  --> $DIR/incorrect-separator.rs:19:28
+   |
+LL |     format!("A number: {}" ̦ iter::once(42).next().unwrap());
+   |                            ^
+
+error: expected `,`, found `.`
+  --> $DIR/incorrect-separator.rs:7:27
+   |
+LL |     format!("A number: {}". iter::once(42).next().unwrap());
+   |                           ^ expected `,`
+
+error: expected `,`, found `/`
+  --> $DIR/incorrect-separator.rs:12:28
+   |
+LL |     format!("A number: {}" / iter::once(42).next().unwrap());
+   |                            ^ expected `,`
+
+error: expected `,`, found `;`
+  --> $DIR/incorrect-separator.rs:15:27
+   |
+LL |     format!("A number: {}"; iter::once(42).next().unwrap());
+   |                           ^ expected `,`
+
+error: expected `,`, found `iter`
+  --> $DIR/incorrect-separator.rs:19:30
+   |
+LL |     format!("A number: {}" ̦ iter::once(42).next().unwrap());
+   |                             ^^^^ expected `,`
+
+error: expected `,`, found `.`
+  --> $DIR/incorrect-separator.rs:26:17
+   |
+LL |     format!("{}". compile_error!("fail"));
+   |                 ^ expected `,`
+
+error: fail
+  --> $DIR/incorrect-separator.rs:26:19
+   |
+LL |     format!("{}". compile_error!("fail"));
+   |                   ^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 7 previous errors
+
diff --git a/tests/ui/fmt/indoc-issue-106408.rs b/tests/ui/fmt/indoc-issue-106408.rs
new file mode 100644
index 000000000..e4e3093b5
--- /dev/null
+++ b/tests/ui/fmt/indoc-issue-106408.rs
@@ -0,0 +1,9 @@
+// aux-build:format-string-proc-macro.rs
+// check-pass
+
+extern crate format_string_proc_macro;
+
+fn main() {
+    let a = 0;
+    format_string_proc_macro::capture_a_with_prepended_space_preserve_span!("{a}");
+}
diff --git a/tests/ui/fmt/issue-103826.rs b/tests/ui/fmt/issue-103826.rs
new file mode 100644
index 000000000..a11ec37a0
--- /dev/null
+++ b/tests/ui/fmt/issue-103826.rs
@@ -0,0 +1,8 @@
+fn main() {
+    format!("{\x7D");
+    //~^ ERROR 1 positional argument in format string, but no arguments were given
+    format!("\x7B\x7D");
+    //~^ ERROR 1 positional argument in format string, but no arguments were given
+    format!("{\x7D {\x7D");
+    //~^ ERROR 2 positional arguments in format string, but no arguments were given
+}
diff --git a/tests/ui/fmt/issue-103826.stderr b/tests/ui/fmt/issue-103826.stderr
new file mode 100644
index 000000000..0f27e1930
--- /dev/null
+++ b/tests/ui/fmt/issue-103826.stderr
@@ -0,0 +1,20 @@
+error: 1 positional argument in format string, but no arguments were given
+  --> $DIR/issue-103826.rs:2:14
+   |
+LL |     format!("{\x7D");
+   |              ^^^^^
+
+error: 1 positional argument in format string, but no arguments were given
+  --> $DIR/issue-103826.rs:4:14
+   |
+LL |     format!("\x7B\x7D");
+   |              ^^^^^^^^
+
+error: 2 positional arguments in format string, but no arguments were given
+  --> $DIR/issue-103826.rs:6:14
+   |
+LL |     format!("{\x7D {\x7D");
+   |              ^^^^^ ^^^^^
+
+error: aborting due to 3 previous errors
+
diff --git a/tests/ui/fmt/issue-104142.rs b/tests/ui/fmt/issue-104142.rs
new file mode 100644
index 000000000..8d7283a71
--- /dev/null
+++ b/tests/ui/fmt/issue-104142.rs
@@ -0,0 +1,6 @@
+fn main() {
+    println!(
+        r#"
+    \"\'}､"# //~ ERROR invalid format string: unmatched `}` found
+    );
+}
diff --git a/tests/ui/fmt/issue-104142.stderr b/tests/ui/fmt/issue-104142.stderr
new file mode 100644
index 000000000..d41644faa
--- /dev/null
+++ b/tests/ui/fmt/issue-104142.stderr
@@ -0,0 +1,10 @@
+error: invalid format string: unmatched `}` found
+  --> $DIR/issue-104142.rs:4:9
+   |
+LL |     \"\'}､"#
+   |         ^ unmatched `}` in format string
+   |
+   = note: if you intended to print `}`, you can escape it using `}}`
+
+error: aborting due to previous error
+
diff --git a/tests/ui/fmt/issue-86085.rs b/tests/ui/fmt/issue-86085.rs
new file mode 100644
index 000000000..63d42b769
--- /dev/null
+++ b/tests/ui/fmt/issue-86085.rs
@@ -0,0 +1,6 @@
+// Tests for an ICE with the fuzzed input below.
+
+fn main ( ) {
+format ! ( concat ! ( r#"lJ𐏿Æ�.𐏿�"# , "r} {}" )     ) ;
+//~^ ERROR: invalid format string: unmatched `}` found
+}
diff --git a/tests/ui/fmt/issue-86085.stderr b/tests/ui/fmt/issue-86085.stderr
new file mode 100644
index 000000000..ee7d8a5cc
--- /dev/null
+++ b/tests/ui/fmt/issue-86085.stderr
@@ -0,0 +1,11 @@
+error: invalid format string: unmatched `}` found
+  --> $DIR/issue-86085.rs:4:12
+   |
+LL | format ! ( concat ! ( r#"lJ𐏿Æ�.𐏿�"# , "r} {}" )     ) ;
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unmatched `}` in format string
+   |
+   = note: if you intended to print `}`, you can escape it using `}}`
+   = note: this error originates in the macro `concat` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to previous error
+
diff --git a/tests/ui/fmt/issue-89173.rs b/tests/ui/fmt/issue-89173.rs
new file mode 100644
index 000000000..fc99af408
--- /dev/null
+++ b/tests/ui/fmt/issue-89173.rs
@@ -0,0 +1,14 @@
+// Regression test for #89173: Make sure a helpful note is issued for
+// printf-style format strings using `*` to specify the width.
+
+fn main() {
+    let num = 0x0abcde;
+    let width = 6;
+    print!("%0*x", width, num);
+    //~^ ERROR: multiple unused formatting arguments
+    //~| NOTE: multiple missing formatting specifiers
+    //~| NOTE: argument never used
+    //~| NOTE: argument never used
+    //~| NOTE: format specifiers use curly braces, and you have to use a positional or named parameter for the width
+    //~| NOTE: printf formatting is not supported
+}
diff --git a/tests/ui/fmt/issue-89173.stderr b/tests/ui/fmt/issue-89173.stderr
new file mode 100644
index 000000000..ddeb769ea
--- /dev/null
+++ b/tests/ui/fmt/issue-89173.stderr
@@ -0,0 +1,18 @@
+error: multiple unused formatting arguments
+  --> $DIR/issue-89173.rs:7:20
+   |
+LL |     print!("%0*x", width, num);
+   |            ------  ^^^^^  ^^^ argument never used
+   |            |       |
+   |            |       argument never used
+   |            multiple missing formatting specifiers
+   |
+note: format specifiers use curly braces, and you have to use a positional or named parameter for the width
+  --> $DIR/issue-89173.rs:7:13
+   |
+LL |     print!("%0*x", width, num);
+   |             ^^^^
+   = note: printf formatting is not supported; see the documentation for `std::fmt`
+
+error: aborting due to previous error
+
diff --git a/tests/ui/fmt/issue-91556.rs b/tests/ui/fmt/issue-91556.rs
new file mode 100644
index 000000000..e782e6f90
--- /dev/null
+++ b/tests/ui/fmt/issue-91556.rs
@@ -0,0 +1,8 @@
+fn main() {
+  let _ = format!(concat!("{0}𝖳𝖾𝗌𝗍{"), i);
+  //~^ ERROR: invalid format string: expected `'}'` but string was terminated
+  //~| NOTE: if you intended to print `{`, you can escape it using `{{`
+  //~| NOTE: in this expansion of concat!
+  //~| NOTE: in this expansion of concat!
+  //~| NOTE: expected `'}'` in format string
+}
diff --git a/tests/ui/fmt/issue-91556.stderr b/tests/ui/fmt/issue-91556.stderr
new file mode 100644
index 000000000..dbd5aef45
--- /dev/null
+++ b/tests/ui/fmt/issue-91556.stderr
@@ -0,0 +1,11 @@
+error: invalid format string: expected `'}'` but string was terminated
+  --> $DIR/issue-91556.rs:2:19
+   |
+LL |   let _ = format!(concat!("{0}𝖳𝖾𝗌𝗍{"), i);
+   |                   ^^^^^^^^^^^^^^^^^^^ expected `'}'` in format string
+   |
+   = note: if you intended to print `{`, you can escape it using `{{`
+   = note: this error originates in the macro `concat` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to previous error
+
diff --git a/tests/ui/fmt/respanned-literal-issue-106191.rs b/tests/ui/fmt/respanned-literal-issue-106191.rs
new file mode 100644
index 000000000..bb741c0ef
--- /dev/null
+++ b/tests/ui/fmt/respanned-literal-issue-106191.rs
@@ -0,0 +1,15 @@
+// aux-build:format-string-proc-macro.rs
+// check-fail
+// known-bug: #106191
+// unset-rustc-env:RUST_BACKTRACE
+// had to be reverted
+// error-pattern:internal compiler error
+// failure-status:101
+// dont-check-compiler-stderr
+
+extern crate format_string_proc_macro;
+
+fn main() {
+    format_string_proc_macro::respan_to_invalid_format_literal!("¡");
+    format_args!(r#concat!("¡        {"));
+}
diff --git a/tests/ui/fmt/respanned-literal-issue-106191.stderr b/tests/ui/fmt/respanned-literal-issue-106191.stderr
new file mode 100644
index 000000000..16717f422
--- /dev/null
+++ b/tests/ui/fmt/respanned-literal-issue-106191.stderr
@@ -0,0 +1,2 @@
+                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  query stack during panic:
+end of query stack
diff --git a/tests/ui/fmt/send-sync.rs b/tests/ui/fmt/send-sync.rs
new file mode 100644
index 000000000..95ec68d1d
--- /dev/null
+++ b/tests/ui/fmt/send-sync.rs
@@ -0,0 +1,10 @@
+fn send<T: Send>(_: T) {}
+fn sync<T: Sync>(_: T) {}
+
+fn main() {
+    // `Cell` is not `Sync`, so `&Cell` is neither `Sync` nor `Send`,
+    // `std::fmt::Arguments` used to forget this...
+    let c = std::cell::Cell::new(42);
+    send(format_args!("{:?}", c)); //~ ERROR E0277
+    sync(format_args!("{:?}", c)); //~ ERROR E0277
+}
diff --git a/tests/ui/fmt/send-sync.stderr b/tests/ui/fmt/send-sync.stderr
new file mode 100644
index 000000000..3ed040c3a
--- /dev/null
+++ b/tests/ui/fmt/send-sync.stderr
@@ -0,0 +1,43 @@
+error[E0277]: `core::fmt::Opaque` cannot be shared between threads safely
+  --> $DIR/send-sync.rs:8:10
+   |
+LL |     send(format_args!("{:?}", c));
+   |     ---- ^^^^^^^^^^^^^^^^^^^^^^^ `core::fmt::Opaque` cannot be shared between threads safely
+   |     |
+   |     required by a bound introduced by this call
+   |
+   = help: within `[ArgumentV1<'_>]`, the trait `Sync` is not implemented for `core::fmt::Opaque`
+   = note: required because it appears within the type `&core::fmt::Opaque`
+   = note: required because it appears within the type `ArgumentV1<'_>`
+   = note: required because it appears within the type `[ArgumentV1<'_>]`
+   = note: required for `&[ArgumentV1<'_>]` to implement `Send`
+   = note: required because it appears within the type `Arguments<'_>`
+note: required by a bound in `send`
+  --> $DIR/send-sync.rs:1:12
+   |
+LL | fn send<T: Send>(_: T) {}
+   |            ^^^^ required by this bound in `send`
+
+error[E0277]: `core::fmt::Opaque` cannot be shared between threads safely
+  --> $DIR/send-sync.rs:9:10
+   |
+LL |     sync(format_args!("{:?}", c));
+   |     ---- ^^^^^^^^^^^^^^^^^^^^^^^ `core::fmt::Opaque` cannot be shared between threads safely
+   |     |
+   |     required by a bound introduced by this call
+   |
+   = help: within `Arguments<'_>`, the trait `Sync` is not implemented for `core::fmt::Opaque`
+   = note: required because it appears within the type `&core::fmt::Opaque`
+   = note: required because it appears within the type `ArgumentV1<'_>`
+   = note: required because it appears within the type `[ArgumentV1<'_>]`
+   = note: required because it appears within the type `&[ArgumentV1<'_>]`
+   = note: required because it appears within the type `Arguments<'_>`
+note: required by a bound in `sync`
+  --> $DIR/send-sync.rs:2:12
+   |
+LL | fn sync<T: Sync>(_: T) {}
+   |            ^^^^ required by this bound in `sync`
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/fmt/struct-field-as-captured-argument.fixed b/tests/ui/fmt/struct-field-as-captured-argument.fixed
new file mode 100644
index 000000000..f7244f674
--- /dev/null
+++ b/tests/ui/fmt/struct-field-as-captured-argument.fixed
@@ -0,0 +1,18 @@
+// run-rustfix
+
+#[derive(Debug)]
+struct Foo {
+    field: usize,
+}
+
+fn main() {
+    let foo = Foo { field: 0 };
+    let bar = 3;
+    format!("{0}", foo.field); //~ ERROR invalid format string: field access isn't supported
+    format!("{1} {} {bar}", "aa", foo.field); //~ ERROR invalid format string: field access isn't supported
+    format!("{2} {} {1} {bar}", "aa", "bb", foo.field); //~ ERROR invalid format string: field access isn't supported
+    format!("{1} {} {baz}", "aa", foo.field, baz = 3); //~ ERROR invalid format string: field access isn't supported
+    format!("{1:?} {} {baz}", "aa", foo.field, baz = 3); //~ ERROR invalid format string: field access isn't supported
+    format!("{1:#?} {} {baz}", "aa", foo.field, baz = 3); //~ ERROR invalid format string: field access isn't supported
+    format!("{1:.3} {} {baz}", "aa", foo.field, baz = 3); //~ ERROR invalid format string: field access isn't supported
+}
diff --git a/tests/ui/fmt/struct-field-as-captured-argument.rs b/tests/ui/fmt/struct-field-as-captured-argument.rs
new file mode 100644
index 000000000..ab5f2552b
--- /dev/null
+++ b/tests/ui/fmt/struct-field-as-captured-argument.rs
@@ -0,0 +1,18 @@
+// run-rustfix
+
+#[derive(Debug)]
+struct Foo {
+    field: usize,
+}
+
+fn main() {
+    let foo = Foo { field: 0 };
+    let bar = 3;
+    format!("{foo.field}"); //~ ERROR invalid format string: field access isn't supported
+    format!("{foo.field} {} {bar}", "aa"); //~ ERROR invalid format string: field access isn't supported
+    format!("{foo.field} {} {1} {bar}", "aa", "bb"); //~ ERROR invalid format string: field access isn't supported
+    format!("{foo.field} {} {baz}", "aa", baz = 3); //~ ERROR invalid format string: field access isn't supported
+    format!("{foo.field:?} {} {baz}", "aa", baz = 3); //~ ERROR invalid format string: field access isn't supported
+    format!("{foo.field:#?} {} {baz}", "aa", baz = 3); //~ ERROR invalid format string: field access isn't supported
+    format!("{foo.field:.3} {} {baz}", "aa", baz = 3); //~ ERROR invalid format string: field access isn't supported
+}
diff --git a/tests/ui/fmt/struct-field-as-captured-argument.stderr b/tests/ui/fmt/struct-field-as-captured-argument.stderr
new file mode 100644
index 000000000..7ea8b4068
--- /dev/null
+++ b/tests/ui/fmt/struct-field-as-captured-argument.stderr
@@ -0,0 +1,79 @@
+error: invalid format string: field access isn't supported
+  --> $DIR/struct-field-as-captured-argument.rs:11:15
+   |
+LL |     format!("{foo.field}");
+   |               ^^^^^^^^^ not supported in format string
+   |
+help: consider using a positional formatting argument instead
+   |
+LL |     format!("{0}", foo.field);
+   |               ~  +++++++++++
+
+error: invalid format string: field access isn't supported
+  --> $DIR/struct-field-as-captured-argument.rs:12:15
+   |
+LL |     format!("{foo.field} {} {bar}", "aa");
+   |               ^^^^^^^^^ not supported in format string
+   |
+help: consider using a positional formatting argument instead
+   |
+LL |     format!("{1} {} {bar}", "aa", foo.field);
+   |               ~                 +++++++++++
+
+error: invalid format string: field access isn't supported
+  --> $DIR/struct-field-as-captured-argument.rs:13:15
+   |
+LL |     format!("{foo.field} {} {1} {bar}", "aa", "bb");
+   |               ^^^^^^^^^ not supported in format string
+   |
+help: consider using a positional formatting argument instead
+   |
+LL |     format!("{2} {} {1} {bar}", "aa", "bb", foo.field);
+   |               ~                           +++++++++++
+
+error: invalid format string: field access isn't supported
+  --> $DIR/struct-field-as-captured-argument.rs:14:15
+   |
+LL |     format!("{foo.field} {} {baz}", "aa", baz = 3);
+   |               ^^^^^^^^^ not supported in format string
+   |
+help: consider using a positional formatting argument instead
+   |
+LL |     format!("{1} {} {baz}", "aa", foo.field, baz = 3);
+   |               ~                 +++++++++++
+
+error: invalid format string: field access isn't supported
+  --> $DIR/struct-field-as-captured-argument.rs:15:15
+   |
+LL |     format!("{foo.field:?} {} {baz}", "aa", baz = 3);
+   |               ^^^^^^^^^ not supported in format string
+   |
+help: consider using a positional formatting argument instead
+   |
+LL |     format!("{1:?} {} {baz}", "aa", foo.field, baz = 3);
+   |               ~                   +++++++++++
+
+error: invalid format string: field access isn't supported
+  --> $DIR/struct-field-as-captured-argument.rs:16:15
+   |
+LL |     format!("{foo.field:#?} {} {baz}", "aa", baz = 3);
+   |               ^^^^^^^^^ not supported in format string
+   |
+help: consider using a positional formatting argument instead
+   |
+LL |     format!("{1:#?} {} {baz}", "aa", foo.field, baz = 3);
+   |               ~                    +++++++++++
+
+error: invalid format string: field access isn't supported
+  --> $DIR/struct-field-as-captured-argument.rs:17:15
+   |
+LL |     format!("{foo.field:.3} {} {baz}", "aa", baz = 3);
+   |               ^^^^^^^^^ not supported in format string
+   |
+help: consider using a positional formatting argument instead
+   |
+LL |     format!("{1:.3} {} {baz}", "aa", foo.field, baz = 3);
+   |               ~                    +++++++++++
+
+error: aborting due to 7 previous errors
+
diff --git a/tests/ui/fmt/unicode-escape-spans.rs b/tests/ui/fmt/unicode-escape-spans.rs
new file mode 100644
index 000000000..753d91ce5
--- /dev/null
+++ b/tests/ui/fmt/unicode-escape-spans.rs
@@ -0,0 +1,19 @@
+fn main() {
+    // 1 byte in UTF-8
+    format!("\u{000041}{a}"); //~ ERROR cannot find value
+    format!("\u{0041}{a}"); //~ ERROR cannot find value
+    format!("\u{41}{a}"); //~ ERROR cannot find value
+    format!("\u{0}{a}"); //~ ERROR cannot find value
+
+    // 2 bytes
+    format!("\u{0df}{a}"); //~ ERROR cannot find value
+    format!("\u{df}{a}"); //~ ERROR cannot find value
+
+    // 3 bytes
+    format!("\u{00211d}{a}"); //~ ERROR cannot find value
+    format!("\u{211d}{a}"); //~ ERROR cannot find value
+
+    // 4 bytes
+    format!("\u{1f4a3}{a}"); //~ ERROR cannot find value
+    format!("\u{10ffff}{a}"); //~ ERROR cannot find value
+}
diff --git a/tests/ui/fmt/unicode-escape-spans.stderr b/tests/ui/fmt/unicode-escape-spans.stderr
new file mode 100644
index 000000000..1d8473f01
--- /dev/null
+++ b/tests/ui/fmt/unicode-escape-spans.stderr
@@ -0,0 +1,63 @@
+error[E0425]: cannot find value `a` in this scope
+  --> $DIR/unicode-escape-spans.rs:3:25
+   |
+LL |     format!("\u{000041}{a}");
+   |                         ^ not found in this scope
+
+error[E0425]: cannot find value `a` in this scope
+  --> $DIR/unicode-escape-spans.rs:4:23
+   |
+LL |     format!("\u{0041}{a}");
+   |                       ^ not found in this scope
+
+error[E0425]: cannot find value `a` in this scope
+  --> $DIR/unicode-escape-spans.rs:5:21
+   |
+LL |     format!("\u{41}{a}");
+   |                     ^ not found in this scope
+
+error[E0425]: cannot find value `a` in this scope
+  --> $DIR/unicode-escape-spans.rs:6:20
+   |
+LL |     format!("\u{0}{a}");
+   |                    ^ not found in this scope
+
+error[E0425]: cannot find value `a` in this scope
+  --> $DIR/unicode-escape-spans.rs:9:22
+   |
+LL |     format!("\u{0df}{a}");
+   |                      ^ not found in this scope
+
+error[E0425]: cannot find value `a` in this scope
+  --> $DIR/unicode-escape-spans.rs:10:21
+   |
+LL |     format!("\u{df}{a}");
+   |                     ^ not found in this scope
+
+error[E0425]: cannot find value `a` in this scope
+  --> $DIR/unicode-escape-spans.rs:13:25
+   |
+LL |     format!("\u{00211d}{a}");
+   |                         ^ not found in this scope
+
+error[E0425]: cannot find value `a` in this scope
+  --> $DIR/unicode-escape-spans.rs:14:23
+   |
+LL |     format!("\u{211d}{a}");
+   |                       ^ not found in this scope
+
+error[E0425]: cannot find value `a` in this scope
+  --> $DIR/unicode-escape-spans.rs:17:24
+   |
+LL |     format!("\u{1f4a3}{a}");
+   |                        ^ not found in this scope
+
+error[E0425]: cannot find value `a` in this scope
+  --> $DIR/unicode-escape-spans.rs:18:25
+   |
+LL |     format!("\u{10ffff}{a}");
+   |                         ^ not found in this scope
+
+error: aborting due to 10 previous errors
+
+For more information about this error, try `rustc --explain E0425`.