问题
I'm trying to get a simple Iron example to work:
extern crate iron;
extern crate router;
use iron::prelude::*;
use iron::status;
use router::Router;
fn main() {
let mut router = Router::new();
router.get("/controller", controller);
fn controller(_: &mut Request) -> IronResult<Response> {
Ok(Response::with((status::Ok, "Hello World!")))
}
Iron::new(router).http("localhost:3000").unwrap();
}
I maintain the following Cargo.toml:
[package]
name = "simple_router"
version = "0.1.0"
authors = ["Thijs"]
[dependencies]
iron="*"
router = "*"
I can see the following error:
type mismatch: the type `fn(&mut iron::Request<'_, '_>) -> std::result::Result<iron::Response, iron::IronError> {main::controller}` implements the trait `for<'r, 'r, 'r> std::ops::Fn<(&'r mut iron::Request<'r, 'r>,)>`, but the trait `for<'r, 'r, 'r> std::ops::Fn<(&'r mut iron::request::Request<'r, 'r>,)>` is required (expected struct `iron::request::Request`, found struct `iron::Request`) [E0281]at line 13 col 12
when running cargo build I got the following:
Compiling SimpleRouter v0.1.0 (file:///home/kolbein/workspaces/simplerust/SimpleRouter)
src/main.rs:13:12: 13:15 error: type mismatch: the type `fn(&mut iron::Request<'_, '_>) -> std::result::Result<iron::Response, iron::IronError> {main::controller}` implements the trait `for<'r, 'r, 'r> std::ops::Fn<(&'r mut iron::Request<'r, 'r>,)>`, but the trait `for<'r, 'r, 'r> std::ops::Fn<(&'r mut iron::request::Request<'r, 'r>,)>` is required (expected struct `iron::request::Request`, found struct `iron::Request`) [E0281]
src/main.rs:13 router.get("/controller", controller);
^~~
src/main.rs:13:12: 13:15 help: run `rustc --explain E0281` to see a detailed explanation
src/main.rs:13:12: 13:15 note: required because of the requirements on the impl of `iron::middleware::Handler` for `fn(&mut iron::Request<'_, '_>) -> std::result::Result<iron::Response, iron::IronError> {main::controller}`
src/main.rs:13:12: 13:15 error: type mismatch: the type `fn(&mut iron::Request<'_, '_>) -> std::result::Result<iron::Response, iron::IronError> {main::controller}` implements the trait `for<'r, 'r, 'r> std::ops::FnOnce<(&'r mut iron::Request<'r, 'r>,)>`, but the trait `for<'r, 'r, 'r> std::ops::FnOnce<(&'r mut iron::request::Request<'r, 'r>,)>` is required (expected struct `iron::request::Request`, found struct `iron::Request`) [E0281]
src/main.rs:13 router.get("/controller", controller);
^~~
src/main.rs:13:12: 13:15 help: run `rustc --explain E0281` to see a detailed explanation
src/main.rs:13:12: 13:15 note: required because of the requirements on the impl of `iron::middleware::Handler` for `fn(&mut iron::Request<'_, '_>) -> std::result::Result<iron::Response, iron::IronError> {main::controller}`
src/main.rs:19:5: 19:14 error: the trait bound `for<'r, 'r, 'r> router::Router: std::ops::Fn<(&'r mut iron::Request<'r, 'r>,)>` is not satisfied [E0277]
src/main.rs:19 Iron::new(router).http("localhost:3000").unwrap();
^~~~~~~~~
src/main.rs:19:5: 19:14 help: run `rustc --explain E0277` to see a detailed explanation
src/main.rs:19:5: 19:14 note: required because of the requirements on the impl of `iron::Handler` for `router::Router`
src/main.rs:19:5: 19:14 note: required by `iron::Iron::new`
src/main.rs:19:5: 19:14 error: the trait bound `for<'r, 'r, 'r> router::Router: std::ops::FnOnce<(&'r mut iron::Request<'r, 'r>,)>` is not satisfied [E0277]
src/main.rs:19 Iron::new(router).http("localhost:3000").unwrap();
^~~~~~~~~
src/main.rs:19:5: 19:14 help: run `rustc --explain E0277` to see a detailed explanation
src/main.rs:19:5: 19:14 note: required because of the requirements on the impl of `iron::Handler` for `router::Router`
src/main.rs:19:5: 19:14 note: required by `iron::Iron::new`
src/main.rs:19:23: 19:27 error: no method named `http` found for type `iron::Iron<router::Router>` in the current scope
src/main.rs:19 Iron::new(router).http("localhost:3000").unwrap();
^~~~
src/main.rs:19:23: 19:27 note: the method `http` exists but the following trait bounds were not satisfied: `router::Router : iron::Handler`
error: aborting due to 5 previous errors
error: Could not compile `SimpleRouter`.
Below you'll find the Cargo.lock file:
[root]
name = "simple_router"
version = "0.1.0"
dependencies = [
"iron 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
"router 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "conduit-mime-types"
version = "0.7.3"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"rustc-serialize 0.3.19 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "cookie"
version = "0.2.5"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"time 0.1.35 (registry+https://github.com/rust-lang/crates.io-index)",
"url 1.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "error"
version = "0.1.9"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"traitobject 0.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
"typeable 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "hpack"
version = "0.2.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "httparse"
version = "1.1.2"
source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "hyper"
version = "0.8.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"cookie 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)",
"httparse 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
"language-tags 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
"log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
"mime 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
"num_cpus 0.2.13 (registry+https://github.com/rust-lang/crates.io-index)",
"rustc-serialize 0.3.19 (registry+https://github.com/rust-lang/crates.io-index)",
"solicit 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)",
"time 0.1.35 (registry+https://github.com/rust-lang/crates.io-index)",
"traitobject 0.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
"typeable 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
"unicase 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
"url 0.5.9 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "hyper"
version = "0.9.10"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"cookie 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)",
"httparse 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
"language-tags 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
"log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
"mime 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
"num_cpus 0.2.13 (registry+https://github.com/rust-lang/crates.io-index)",
"rustc-serialize 0.3.19 (registry+https://github.com/rust-lang/crates.io-index)",
"solicit 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)",
"time 0.1.35 (registry+https://github.com/rust-lang/crates.io-index)",
"traitobject 0.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
"typeable 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
"unicase 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
"url 1.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "idna"
version = "0.1.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"matches 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
"unicode-bidi 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
"unicode-normalization 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "iron"
version = "0.3.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"conduit-mime-types 0.7.3 (registry+https://github.com/rust-lang/crates.io-index)",
"error 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
"hyper 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
"lazy_static 0.1.16 (registry+https://github.com/rust-lang/crates.io-index)",
"log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
"modifier 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
"num_cpus 0.2.13 (registry+https://github.com/rust-lang/crates.io-index)",
"plugin 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
"typemap 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
"url 0.5.9 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "iron"
version = "0.4.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"conduit-mime-types 0.7.3 (registry+https://github.com/rust-lang/crates.io-index)",
"error 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
"hyper 0.9.10 (registry+https://github.com/rust-lang/crates.io-index)",
"lazy_static 0.1.16 (registry+https://github.com/rust-lang/crates.io-index)",
"log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
"modifier 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
"num_cpus 0.2.13 (registry+https://github.com/rust-lang/crates.io-index)",
"plugin 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
"typemap 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
"url 1.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "kernel32-sys"
version = "0.2.2"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
"winapi-build 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "language-tags"
version = "0.2.2"
source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "lazy_static"
version = "0.1.16"
source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "libc"
version = "0.2.14"
source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "log"
version = "0.3.6"
source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "matches"
version = "0.1.2"
source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "mime"
version = "0.2.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "modifier"
version = "0.1.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "num_cpus"
version = "0.2.13"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"libc 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "plugin"
version = "0.2.6"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"typemap 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "rand"
version = "0.3.14"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"libc 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "route-recognizer"
version = "0.1.11"
source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "router"
version = "0.1.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"iron 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
"route-recognizer 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "rustc-serialize"
version = "0.3.19"
source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "rustc_version"
version = "0.1.7"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"semver 0.1.20 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "semver"
version = "0.1.20"
source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "solicit"
version = "0.4.4"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"hpack 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
"log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "time"
version = "0.1.35"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
"libc 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)",
"winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "traitobject"
version = "0.0.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "traitobject"
version = "0.0.3"
source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "typeable"
version = "0.1.2"
source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "typemap"
version = "0.3.3"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"unsafe-any 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "unicase"
version = "1.4.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"rustc_version 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "unicode-bidi"
version = "0.2.3"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"matches 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "unicode-normalization"
version = "0.1.2"
source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "unsafe-any"
version = "0.4.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"traitobject 0.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "url"
version = "0.5.9"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"matches 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
"rustc-serialize 0.3.19 (registry+https://github.com/rust-lang/crates.io-index)",
"unicode-bidi 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
"unicode-normalization 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
"uuid 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "url"
version = "1.1.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"idna 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
"matches 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "uuid"
version = "0.2.2"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"rand 0.3.14 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "winapi"
version = "0.2.8"
source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "winapi-build"
version = "0.1.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
I should add more details. What more details can I add..
回答1:
See also Cannot access parameters in Iron because the trait bound plugin::Plugin<iron::Request> is not satisfied
You are including an old version of router that replies on Iron 0.3:
[[package]]
name = "router"
version = "0.1.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"iron 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
"route-recognizer 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)",
]
But then are using Iron 0.4 directly:
[[package]]
name = "iron"
version = "0.4.0"
Different crate versions act as completely separate crates (even though they look similar in error messages). It's not valid to mix and match the versions in this manner.
回答2:
I removed the Cargo.lock file and rebuilt and it works as expected.
来源：https://stackoverflow.com/questions/38659008/unable-to-compile-iron-example-expected-struct-ironrequestrequest-found