Crate assert_matches2

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A replacement for the assert_matches crate, providing an assert_matches! macro without support for if guards and the extra arm, but bringing any names introduced in the pattern into scope for after the macro invocation, by expanding to let else.


use assert_matches2::assert_matches;

/// Basic usage
let var = serde_json::Value::from("a string");
assert_matches!(var, serde_json::Value::String(s));
assert_eq!(s, "a string");

// More complex usages
struct Foo {
    bar: Bar,

enum Bar {
    V2 { field: String },

let var = Foo { bar: Bar::V1(10) };
assert_matches!(var, Foo { bar: ref r @ Bar::V1(int) });
assert_matches!(r, Bar::V1(_));
assert_eq!(int, 10);

let var = Foo { bar: Bar::V2 { field: "test".to_owned() } };
assert_matches!(var, Foo { bar: Bar::V2 { field: rename } });
assert_eq!(rename, "test");


  • Alternative form of assert_matches! where the pattern comes first.
  • Assert that the given expression matches the given pattern, and introduce any bindings from the pattern into the surrounding scope.