mirror of https://github.com/rust-lang/rust
90 lines
2.3 KiB
Rust
90 lines
2.3 KiB
Rust
//@ run-pass
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fn main() {
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named_argument_takes_precedence_to_captured();
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formatting_parameters_can_be_captured();
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capture_raw_strings_and_idents();
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repeated_capture();
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#[cfg(panic = "unwind")]
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{
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panic_with_single_argument_does_not_get_formatted();
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panic_with_multiple_arguments_is_formatted();
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}
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}
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fn named_argument_takes_precedence_to_captured() {
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let foo = "captured";
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let s = format!("{foo}", foo = "named");
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assert_eq!(&s, "named");
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let s = format!("{foo}-{foo}-{foo}", foo = "named");
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assert_eq!(&s, "named-named-named");
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let s = format!("{}-{bar}-{foo}", "positional", bar = "named");
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assert_eq!(&s, "positional-named-captured");
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}
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fn capture_raw_strings_and_idents() {
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let r#type = "apple";
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let s = format!(r#"The fruit is an {type}"#);
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assert_eq!(&s, "The fruit is an apple");
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let r#type = "orange";
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let s = format!(r"The fruit is an {type}");
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assert_eq!(&s, "The fruit is an orange");
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}
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#[cfg(panic = "unwind")]
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fn panic_with_single_argument_does_not_get_formatted() {
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// panic! with a single argument does not perform string formatting.
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// RFC #2795 suggests that this may need to change so that captured arguments are formatted.
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// For stability reasons this will need to part of an edition change.
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#[allow(non_fmt_panics)]
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let msg = std::panic::catch_unwind(|| {
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panic!("{foo}");
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})
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.unwrap_err();
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assert_eq!(msg.downcast_ref::<&str>(), Some(&"{foo}"))
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}
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#[cfg(panic = "unwind")]
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fn panic_with_multiple_arguments_is_formatted() {
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let foo = "captured";
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let msg = std::panic::catch_unwind(|| {
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panic!("{}-{bar}-{foo}", "positional", bar = "named");
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})
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.unwrap_err();
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assert_eq!(msg.downcast_ref::<String>(), Some(&"positional-named-captured".to_string()))
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}
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fn formatting_parameters_can_be_captured() {
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let width = 9;
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let precision = 3;
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let x = 7.0;
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let s = format!("{x:width$}");
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assert_eq!(&s, " 7");
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let s = format!("{x:<width$}");
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assert_eq!(&s, "7 ");
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let s = format!("{x:-^width$}");
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assert_eq!(&s, "----7----");
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let s = format!("{x:-^width$.precision$}");
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assert_eq!(&s, "--7.000--");
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}
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fn repeated_capture() {
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let a = 1;
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let b = 2;
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let s = format!("{a} {b} {a}");
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assert_eq!(&s, "1 2 1");
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}
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