Use proper span in responder codegen output.

core/codegen/src/attribute/route.rs

@@ -339,6 +339,24 @@ fn generate_internal_uri_macro(route: &Route) -> TokenStream2 {
     }
 }
 
+fn generate_respond_expr(route: &Route) -> TokenStream2 {
+    let ret_span = match route.function.decl.output {
+        syn::ReturnType::Default => route.function.ident.span(),
+        syn::ReturnType::Type(_, ref ty) => ty.span().into()
+    };
+
+    define_vars_and_mods!(req);
+    define_vars_and_mods!(ret_span => handler);
+    let user_handler_fn_name = &route.function.ident;
+    let parameter_names = route.inputs.iter()
+        .map(|(_, rocket_ident, _)| rocket_ident);
+
+    quote_spanned! { ret_span =>
+        let ___responder = #user_handler_fn_name(#(#parameter_names),*);
+        #handler::Outcome::from(#req, ___responder)
+    }
+}
+
 fn codegen_route(route: Route) -> Result<TokenStream> {
     // Generate the declarations for path, data, and request guard parameters.
     let mut data_stmt = None;
@@ -372,8 +390,9 @@ fn codegen_route(route: Route) -> Result<TokenStream> {
     let user_handler_fn_name = &user_handler_fn.ident;
     let generated_fn_name = user_handler_fn_name.prepend(ROUTE_FN_PREFIX);
     let generated_struct_name = user_handler_fn_name.prepend(ROUTE_STRUCT_PREFIX);
-    let parameter_names = route.inputs.iter().map(|(_, rocket_ident, _)| rocket_ident);
     let generated_internal_uri_macro = generate_internal_uri_macro(&route);
+    let generated_respond_expr = generate_respond_expr(&route);
+
     let method = route.attribute.method;
     let path = route.attribute.path.origin.0.to_string();
     let rank = Optional(route.attribute.rank);
@@ -391,8 +410,7 @@ fn codegen_route(route: Route) -> Result<TokenStream> {
             #(#parameter_definitions)*
             #data_stmt
 
-            let ___responder = #user_handler_fn_name(#(#parameter_names),*);
-            #handler::Outcome::from(#req, ___responder)
+            #generated_respond_expr
         }
 
         /// Rocket code generated wrapping URI macro.

core/codegen/tests/ui-fail/catch_type_errors.rs

@@ -4,13 +4,13 @@ use rocket::Request;
 
 #[catch(404)]
 fn f1(_request: &Request) -> usize {
-    //~^^ ERROR usize: rocket::response::Responder
+    //~^ ERROR usize: rocket::response::Responder
     10
 }
 
 #[catch(404)]
 fn f2(_request: &Request) -> bool {
-    //~^^ ERROR bool: rocket::response::Responder
+    //~^ ERROR bool: rocket::response::Responder
     false
 }
 
@@ -22,7 +22,7 @@ fn f3(_request: bool) -> usize {
 
 #[catch(404)]
 fn f4() -> usize {
-    //~^^ ERROR usize: rocket::response::Responder
+    //~^ ERROR usize: rocket::response::Responder
     10
 }
 

core/codegen/tests/ui-fail/catch_type_errors.stderr

@@ -1,20 +1,18 @@
 error[E0277]: the trait bound `usize: rocket::response::Responder<'_>` is not satisfied
- --> $DIR/catch_type_errors.rs:5:1
+ --> $DIR/catch_type_errors.rs:6:30
   |
-5 | #[catch(404)]
-  | ^^^^^^^^^^^^^ the trait `rocket::response::Responder<'_>` is not implemented for `usize`
+6 | fn f1(_request: &Request) -> usize {
+  |                              ^^^^^ the trait `rocket::response::Responder<'_>` is not implemented for `usize`
   |
   = note: required by `rocket::response::Responder::respond_to`
-  = note: this error originates in an attribute macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0277]: the trait bound `bool: rocket::response::Responder<'_>` is not satisfied
-  --> $DIR/catch_type_errors.rs:11:1
+  --> $DIR/catch_type_errors.rs:12:30
    |
-11 | #[catch(404)]
-   | ^^^^^^^^^^^^^ the trait `rocket::response::Responder<'_>` is not implemented for `bool`
+12 | fn f2(_request: &Request) -> bool {
+   |                              ^^^^ the trait `rocket::response::Responder<'_>` is not implemented for `bool`
    |
    = note: required by `rocket::response::Responder::respond_to`
-   = note: this error originates in an attribute macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0308]: mismatched types
   --> $DIR/catch_type_errors.rs:18:7
@@ -28,13 +26,12 @@ error[E0308]: mismatched types
                  found fn item `fn(bool) -> usize {f3}`
 
 error[E0277]: the trait bound `usize: rocket::response::Responder<'_>` is not satisfied
-  --> $DIR/catch_type_errors.rs:23:1
+  --> $DIR/catch_type_errors.rs:24:12
    |
-23 | #[catch(404)]
-   | ^^^^^^^^^^^^^ the trait `rocket::response::Responder<'_>` is not implemented for `usize`
+24 | fn f4() -> usize {
+   |            ^^^^^ the trait `rocket::response::Responder<'_>` is not implemented for `usize`
    |
    = note: required by `rocket::response::Responder::respond_to`
-   = note: this error originates in an attribute macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: aborting due to 4 previous errors
 

core/codegen/tests/ui-fail/responder-types.rs

@@ -1,5 +1,8 @@
 // normalize-stderr-test: "<(.*) as (.*)>" -> "$1 as $$TRAIT"
 // normalize-stderr-test: "and \d+ others" -> "and $$N others"
+// normalize-stderr-test: "::: [^\.]*" -> "::: $$FILE"
+
+#![feature(proc_macro_hygiene, decl_macro)]
 
 #[macro_use] extern crate rocket;
 
@@ -32,4 +35,8 @@ struct Thing4 {
     //~^ ERROR Header
 }
 
+#[get("/")]
+fn foo() -> usize { 0 }
+//~^ ERROR Responder
+
 fn main() {  }

core/codegen/tests/ui-fail/responder-types.stderr

@@ -1,15 +1,15 @@
 error[E0277]: the trait bound `u8: rocket::response::Responder<'_>` is not satisfied
- --> $DIR/responder-types.rs:8:5
-  |
-8 |     thing: u8,
-  |     ^^^^^^^^^ the trait `rocket::response::Responder<'_>` is not implemented for `u8`
-  |
-  = note: required by `rocket::response::Responder::respond_to`
+  --> $DIR/responder-types.rs:11:5
+   |
+11 |     thing: u8,
+   |     ^^^^^^^^^ the trait `rocket::response::Responder<'_>` is not implemented for `u8`
+   |
+   = note: required by `rocket::response::Responder::respond_to`
 
 error[E0277]: the trait bound `rocket::http::Header<'_>: std::convert::From<u8>` is not satisfied
-  --> $DIR/responder-types.rs:15:5
+  --> $DIR/responder-types.rs:18:5
    |
-15 |     other: u8,
+18 |     other: u8,
    |     ^^^^^^^^^ the trait `std::convert::From<u8>` is not implemented for `rocket::http::Header<'_>`
    |
    = help: the following implementations were found:
@@ -21,17 +21,17 @@ error[E0277]: the trait bound `rocket::http::Header<'_>: std::convert::From<u8>`
    = note: required because of the requirements on the impl of `std::convert::Into<rocket::http::Header<'_>>` for `u8`
 
 error[E0277]: the trait bound `u8: rocket::response::Responder<'_>` is not satisfied
-  --> $DIR/responder-types.rs:21:5
+  --> $DIR/responder-types.rs:24:5
    |
-21 |     thing: u8,
+24 |     thing: u8,
    |     ^^^^^^^^^ the trait `rocket::response::Responder<'_>` is not implemented for `u8`
    |
    = note: required by `rocket::response::Responder::respond_to`
 
 error[E0277]: the trait bound `rocket::http::Header<'_>: std::convert::From<u8>` is not satisfied
-  --> $DIR/responder-types.rs:23:5
+  --> $DIR/responder-types.rs:26:5
    |
-23 |     other: u8,
+26 |     other: u8,
    |     ^^^^^^^^^ the trait `std::convert::From<u8>` is not implemented for `rocket::http::Header<'_>`
    |
    = help: the following implementations were found:
@@ -43,9 +43,9 @@ error[E0277]: the trait bound `rocket::http::Header<'_>: std::convert::From<u8>`
    = note: required because of the requirements on the impl of `std::convert::Into<rocket::http::Header<'_>>` for `u8`
 
 error[E0277]: the trait bound `rocket::http::Header<'_>: std::convert::From<std::string::String>` is not satisfied
-  --> $DIR/responder-types.rs:31:5
+  --> $DIR/responder-types.rs:34:5
    |
-31 |     then: String,
+34 |     then: String,
    |     ^^^^^^^^^^^^ the trait `std::convert::From<std::string::String>` is not implemented for `rocket::http::Header<'_>`
    |
    = help: the following implementations were found:
@@ -56,6 +56,17 @@ error[E0277]: the trait bound `rocket::http::Header<'_>: std::convert::From<std:
            and $N others
    = note: required because of the requirements on the impl of `std::convert::Into<rocket::http::Header<'_>>` for `std::string::String`
 
-error: aborting due to 5 previous errors
+error[E0277]: the trait bound `usize: rocket::response::Responder<'_>` is not satisfied
+   --> $DIR/responder-types.rs:39:13
+    |
+39  | fn foo() -> usize { 0 }
+    |             ^^^^^ the trait `rocket::response::Responder<'_>` is not implemented for `usize`
+    | 
+   ::: $FILE.rs:202:20
+    |
+202 |     pub fn from<T: Responder<'r>>(req: &Request, responder: T) -> Outcome<'r> {
+    |                    ------------- required by this bound in `rocket::handler::<impl rocket::Outcome<rocket::Response<'r>, rocket::http::Status, rocket::Data>>::from`
+
+error: aborting due to 6 previous errors
 
 For more information about this error, try `rustc --explain E0277`.