Add anyhow::Ok

Closes #192.

Author: dtolnay

src/lib.rs

@@ -602,6 +602,30 @@ pub trait Context<T, E>: context::private::Sealed {
         F: FnOnce() -> C;
 }
 
+/// Equivalent to `Ok::<_, anyhow::Error>(value)`.
+///
+/// This simplifies creation of an anyhow::Result in places where type inference
+/// cannot deduce the `E` type of the result &mdash; without needing to write
+/// `Ok::<_, anyhow::Error>(value)`.
+///
+/// One might think that `anyhow::Result::Ok(value)` would work in such cases
+/// but it does not.
+///
+/// ```console
+/// error[E0282]: type annotations needed for `std::result::Result<i32, E>`
+///   --> src/main.rs:11:13
+///    |
+/// 11 |     let _ = anyhow::Result::Ok(1);
+///    |         -   ^^^^^^^^^^^^^^^^^^ cannot infer type for type parameter `E` declared on the enum `Result`
+///    |         |
+///    |         consider giving this pattern the explicit type `std::result::Result<i32, E>`, where the type parameter `E` is specified
+/// ```
+#[doc(hidden)]
+#[allow(non_snake_case)]
+pub fn Ok<T>(t: T) -> Result<T> {
+    Result::Ok(t)
+}
+
 // Not public API. Referenced by macro-generated code.
 #[doc(hidden)]
 pub mod private {