Rollup merge of rust-lang#68884 - Zoxc:gen-type, r=nikomatsakis

Make the `type_of` return a generic type for generators

Fixes rust-lang#67651.

r? @nikomatsakis

src/librustc_mir_build/build/mod.rs

@@ -139,7 +139,8 @@ fn mir_build(tcx: TyCtxt<'_>, def_id: DefId) -> BodyAndCache<'_> {
             let arguments = implicit_argument.into_iter().chain(explicit_arguments);
 
             let (yield_ty, return_ty) = if body.generator_kind.is_some() {
-                let gen_sig = match ty.kind {
+                let gen_ty = tcx.body_tables(body_id).node_type(id);
+                let gen_sig = match gen_ty.kind {
                     ty::Generator(_, gen_substs, ..) => gen_substs.as_generator().sig(),
                     _ => span_bug!(tcx.hir().span(id), "generator w/o generator type: {:?}", ty),
                 };

src/librustc_typeck/collect/type_of.rs

@@ -188,12 +188,12 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: DefId) -> Ty<'_> {
         Node::Field(field) => icx.to_ty(&field.ty),
 
         Node::Expr(&Expr { kind: ExprKind::Closure(.., gen), .. }) => {
-            if gen.is_some() {
-                return tcx.typeck_tables_of(def_id).node_type(hir_id);
-            }
-
             let substs = InternalSubsts::identity_for_item(tcx, def_id);
-            tcx.mk_closure(def_id, substs)
+            if let Some(movability) = gen {
+                tcx.mk_generator(def_id, substs, movability)
+            } else {
+                tcx.mk_closure(def_id, substs)
+            }
         }
 
         Node::AnonConst(_) => {

src/test/ui/async-await/async-block-control-flow-static-semantics.stderr

@@ -18,22 +18,6 @@ LL | |             break 0u8;
 LL | |         };
    | |_________- enclosing `async` block
 
-error[E0308]: mismatched types
-  --> $DIR/async-block-control-flow-static-semantics.rs:13:43
-   |
-LL | fn return_targets_async_block_not_fn() -> u8 {
-   |    ---------------------------------      ^^ expected `u8`, found `()`
-   |    |
-   |    implicitly returns `()` as its body has no tail or `return` expression
-
-error[E0271]: type mismatch resolving `<impl std::future::Future as std::future::Future>::Output == ()`
-  --> $DIR/async-block-control-flow-static-semantics.rs:18:39
-   |
-LL |     let _: &dyn Future<Output = ()> = &block;
-   |                                       ^^^^^^ expected `()`, found `u8`
-   |
-   = note: required for the cast to the object type `dyn std::future::Future<Output = ()>`
-
 error[E0308]: mismatched types
   --> $DIR/async-block-control-flow-static-semantics.rs:22:58
    |
@@ -55,6 +39,22 @@ LL |     let _: &dyn Future<Output = ()> = &block;
    |
    = note: required for the cast to the object type `dyn std::future::Future<Output = ()>`
 
+error[E0308]: mismatched types
+  --> $DIR/async-block-control-flow-static-semantics.rs:13:43
+   |
+LL | fn return_targets_async_block_not_fn() -> u8 {
+   |    ---------------------------------      ^^ expected `u8`, found `()`
+   |    |
+   |    implicitly returns `()` as its body has no tail or `return` expression
+
+error[E0271]: type mismatch resolving `<impl std::future::Future as std::future::Future>::Output == ()`
+  --> $DIR/async-block-control-flow-static-semantics.rs:18:39
+   |
+LL |     let _: &dyn Future<Output = ()> = &block;
+   |                                       ^^^^^^ expected `()`, found `u8`
+   |
+   = note: required for the cast to the object type `dyn std::future::Future<Output = ()>`
+
 error[E0308]: mismatched types
   --> $DIR/async-block-control-flow-static-semantics.rs:48:44
    |

src/test/ui/async-await/async-error-span.rs

@@ -5,6 +5,7 @@
 use std::future::Future;
 
 fn get_future() -> impl Future<Output = ()> {
+//~^ ERROR the trait bound `(): std::future::Future` is not satisfied
     panic!()
 }
 

src/test/ui/async-await/async-error-span.stderr

@@ -1,15 +1,27 @@
+error[E0277]: the trait bound `(): std::future::Future` is not satisfied
+  --> $DIR/async-error-span.rs:7:20
+   |
+LL | fn get_future() -> impl Future<Output = ()> {
+   |                    ^^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::future::Future` is not implemented for `()`
+LL |
+LL |     panic!()
+   |     -------- this returned value is of type `!`
+   |
+   = note: the return type of a function must have a statically known size
+
 error[E0698]: type inside `async fn` body must be known in this context
-  --> $DIR/async-error-span.rs:12:9
+  --> $DIR/async-error-span.rs:13:9
    |
 LL |     let a;
    |         ^ cannot infer type
    |
 note: the type is part of the `async fn` body because of this `await`
-  --> $DIR/async-error-span.rs:13:5
+  --> $DIR/async-error-span.rs:14:5
    |
 LL |     get_future().await;
    |     ^^^^^^^^^^^^^^^^^^
 
-error: aborting due to previous error
+error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0698`.
+Some errors have detailed explanations: E0277, E0698.
+For more information about an error, try `rustc --explain E0277`.

src/test/ui/async-await/await-keyword/incorrect-syntax-suggestions.rs

@@ -62,6 +62,7 @@ fn foo10() -> Result<(), ()> {
 fn foo11() -> Result<(), ()> {
     let _ = await bar()?; //~ ERROR `await` is only allowed inside `async` functions and blocks
     //~^ ERROR incorrect use of `await`
+    //~| ERROR the `?` operator can only be applied to values that implement `std::ops::Try`
     Ok(())
 }
 fn foo12() -> Result<(), ()> {

src/test/ui/async-await/await-keyword/incorrect-syntax-suggestions.stderr

@@ -71,63 +71,63 @@ LL |     let _ = await bar()?;
    |             ^^^^^^^^^^^^ help: `await` is a postfix operation: `bar()?.await`
 
 error: incorrect use of `await`
-  --> $DIR/incorrect-syntax-suggestions.rs:68:14
+  --> $DIR/incorrect-syntax-suggestions.rs:69:14
    |
 LL |     let _ = (await bar())?;
    |              ^^^^^^^^^^^ help: `await` is a postfix operation: `bar().await`
 
 error: incorrect use of `await`
-  --> $DIR/incorrect-syntax-suggestions.rs:73:24
+  --> $DIR/incorrect-syntax-suggestions.rs:74:24
    |
 LL |     let _ = bar().await();
    |                        ^^ help: `await` is not a method call, remove the parentheses
 
 error: incorrect use of `await`
-  --> $DIR/incorrect-syntax-suggestions.rs:78:24
+  --> $DIR/incorrect-syntax-suggestions.rs:79:24
    |
 LL |     let _ = bar().await()?;
    |                        ^^ help: `await` is not a method call, remove the parentheses
 
 error: incorrect use of `await`
-  --> $DIR/incorrect-syntax-suggestions.rs:106:13
+  --> $DIR/incorrect-syntax-suggestions.rs:107:13
    |
 LL |     let _ = await!(bar());
    |             ^^^^^^^^^^^^^ help: `await` is a postfix operation: `bar().await`
 
 error: incorrect use of `await`
-  --> $DIR/incorrect-syntax-suggestions.rs:110:13
+  --> $DIR/incorrect-syntax-suggestions.rs:111:13
    |
 LL |     let _ = await!(bar())?;
    |             ^^^^^^^^^^^^^ help: `await` is a postfix operation: `bar().await`
 
 error: incorrect use of `await`
-  --> $DIR/incorrect-syntax-suggestions.rs:115:17
+  --> $DIR/incorrect-syntax-suggestions.rs:116:17
    |
 LL |         let _ = await!(bar())?;
    |                 ^^^^^^^^^^^^^ help: `await` is a postfix operation: `bar().await`
 
 error: incorrect use of `await`
-  --> $DIR/incorrect-syntax-suggestions.rs:123:17
+  --> $DIR/incorrect-syntax-suggestions.rs:124:17
    |
 LL |         let _ = await!(bar())?;
    |                 ^^^^^^^^^^^^^ help: `await` is a postfix operation: `bar().await`
 
 error: expected expression, found `=>`
-  --> $DIR/incorrect-syntax-suggestions.rs:131:25
+  --> $DIR/incorrect-syntax-suggestions.rs:132:25
    |
 LL |     match await { await => () }
    |                   ----- ^^ expected expression
    |                   |
    |                   while parsing this incorrect await expression
 
 error: incorrect use of `await`
-  --> $DIR/incorrect-syntax-suggestions.rs:131:11
+  --> $DIR/incorrect-syntax-suggestions.rs:132:11
    |
 LL |     match await { await => () }
    |           ^^^^^^^^^^^^^^^^^^^^^ help: `await` is a postfix operation: `{ await => () }.await`
 
 error: expected one of `.`, `?`, `{`, or an operator, found `}`
-  --> $DIR/incorrect-syntax-suggestions.rs:134:1
+  --> $DIR/incorrect-syntax-suggestions.rs:135:1
    |
 LL |     match await { await => () }
    |     -----                      - expected one of `.`, `?`, `{`, or an operator
@@ -162,71 +162,71 @@ LL |     let _ = await bar()?;
    |             ^^^^^^^^^^^^ only allowed inside `async` functions and blocks
 
 error[E0728]: `await` is only allowed inside `async` functions and blocks
-  --> $DIR/incorrect-syntax-suggestions.rs:68:14
+  --> $DIR/incorrect-syntax-suggestions.rs:69:14
    |
 LL | fn foo12() -> Result<(), ()> {
    |    ----- this is not `async`
 LL |     let _ = (await bar())?;
    |              ^^^^^^^^^^^ only allowed inside `async` functions and blocks
 
 error[E0728]: `await` is only allowed inside `async` functions and blocks
-  --> $DIR/incorrect-syntax-suggestions.rs:73:13
+  --> $DIR/incorrect-syntax-suggestions.rs:74:13
    |
 LL | fn foo13() -> Result<(), ()> {
    |    ----- this is not `async`
 LL |     let _ = bar().await();
    |             ^^^^^^^^^^^ only allowed inside `async` functions and blocks
 
 error[E0728]: `await` is only allowed inside `async` functions and blocks
-  --> $DIR/incorrect-syntax-suggestions.rs:78:13
+  --> $DIR/incorrect-syntax-suggestions.rs:79:13
    |
 LL | fn foo14() -> Result<(), ()> {
    |    ----- this is not `async`
 LL |     let _ = bar().await()?;
    |             ^^^^^^^^^^^ only allowed inside `async` functions and blocks
 
 error[E0728]: `await` is only allowed inside `async` functions and blocks
-  --> $DIR/incorrect-syntax-suggestions.rs:83:13
+  --> $DIR/incorrect-syntax-suggestions.rs:84:13
    |
 LL | fn foo15() -> Result<(), ()> {
    |    ----- this is not `async`
 LL |     let _ = bar().await;
    |             ^^^^^^^^^^^ only allowed inside `async` functions and blocks
 
 error[E0728]: `await` is only allowed inside `async` functions and blocks
-  --> $DIR/incorrect-syntax-suggestions.rs:87:13
+  --> $DIR/incorrect-syntax-suggestions.rs:88:13
    |
 LL | fn foo16() -> Result<(), ()> {
    |    ----- this is not `async`
 LL |     let _ = bar().await?;
    |             ^^^^^^^^^^^ only allowed inside `async` functions and blocks
 
 error[E0728]: `await` is only allowed inside `async` functions and blocks
-  --> $DIR/incorrect-syntax-suggestions.rs:92:17
+  --> $DIR/incorrect-syntax-suggestions.rs:93:17
    |
 LL |     fn foo() -> Result<(), ()> {
    |        --- this is not `async`
 LL |         let _ = bar().await?;
    |                 ^^^^^^^^^^^ only allowed inside `async` functions and blocks
 
 error[E0728]: `await` is only allowed inside `async` functions and blocks
-  --> $DIR/incorrect-syntax-suggestions.rs:99:17
+  --> $DIR/incorrect-syntax-suggestions.rs:100:17
    |
 LL |     let foo = || {
    |               -- this is not `async`
 LL |         let _ = bar().await?;
    |                 ^^^^^^^^^^^ only allowed inside `async` functions and blocks
 
 error[E0728]: `await` is only allowed inside `async` functions and blocks
-  --> $DIR/incorrect-syntax-suggestions.rs:115:17
+  --> $DIR/incorrect-syntax-suggestions.rs:116:17
    |
 LL |     fn foo() -> Result<(), ()> {
    |        --- this is not `async`
 LL |         let _ = await!(bar())?;
    |                 ^^^^^^^^^^^^^ only allowed inside `async` functions and blocks
 
 error[E0728]: `await` is only allowed inside `async` functions and blocks
-  --> $DIR/incorrect-syntax-suggestions.rs:123:17
+  --> $DIR/incorrect-syntax-suggestions.rs:124:17
    |
 LL |     let foo = || {
    |               -- this is not `async`
@@ -242,7 +242,16 @@ LL |     let _ = await bar()?;
    = help: the trait `std::ops::Try` is not implemented for `impl std::future::Future`
    = note: required by `std::ops::Try::into_result`
 
-error: aborting due to 35 previous errors
+error[E0277]: the `?` operator can only be applied to values that implement `std::ops::Try`
+  --> $DIR/incorrect-syntax-suggestions.rs:63:19
+   |
+LL |     let _ = await bar()?;
+   |                   ^^^^^^ the `?` operator cannot be applied to type `impl std::future::Future`
+   |
+   = help: the trait `std::ops::Try` is not implemented for `impl std::future::Future`
+   = note: required by `std::ops::Try::into_result`
+
+error: aborting due to 36 previous errors
 
 Some errors have detailed explanations: E0277, E0728.
 For more information about an error, try `rustc --explain E0277`.

src/test/ui/async-await/issue-67651.rs

@@ -0,0 +1,20 @@
+// edition:2018
+
+trait From {
+    fn from();
+}
+
+impl From for () {
+    fn from() {}
+}
+
+impl From for () {
+//~^ ERROR conflicting implementations of trait
+    fn from() {}
+}
+
+fn bar() -> impl core::future::Future<Output = ()> {
+    async move { From::from() }
+}
+
+fn main() {}

src/test/ui/async-await/issue-67651.stderr

@@ -0,0 +1,12 @@
+error[E0119]: conflicting implementations of trait `From` for type `()`:
+  --> $DIR/issue-67651.rs:11:1
+   |
+LL | impl From for () {
+   | ---------------- first implementation here
+...
+LL | impl From for () {
+   | ^^^^^^^^^^^^^^^^ conflicting implementation for `()`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0119`.

src/test/ui/async-await/issues/issue-63388-2.rs

@@ -8,7 +8,7 @@ trait Foo {}
 
 impl Xyz {
     async fn do_sth<'a>(
-        foo: &dyn Foo, bar: &'a dyn Foo //~ ERROR cannot infer
+        foo: &dyn Foo, bar: &'a dyn Foo
     ) -> &dyn Foo //~ ERROR missing lifetime specifier
     {
         foo

src/test/ui/async-await/issues/issue-63388-2.stderr

@@ -8,21 +8,6 @@ LL |     ) -> &dyn Foo
    |
    = help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from `foo` or `bar`
 
-error: cannot infer an appropriate lifetime
-  --> $DIR/issue-63388-2.rs:11:9
-   |
-LL |         foo: &dyn Foo, bar: &'a dyn Foo
-   |         ^^^ ...but this borrow...
-...
-LL |         foo
-   |         --- this return type evaluates to the `'static` lifetime...
-   |
-note: ...can't outlive the lifetime `'_` as defined on the method body at 11:14
-  --> $DIR/issue-63388-2.rs:11:14
-   |
-LL |         foo: &dyn Foo, bar: &'a dyn Foo
-   |              ^
-
-error: aborting due to 2 previous errors
+error: aborting due to previous error
 
 For more information about this error, try `rustc --explain E0106`.

src/test/ui/async-await/issues/issue-65159.rs

@@ -5,6 +5,7 @@
 async fn copy() -> Result<()> //~ ERROR wrong number of type arguments
 {
     Ok(())
+    //~^ type annotations needed
 }
 
 fn main() { }

src/test/ui/async-await/issues/issue-65159.stderr

@@ -4,6 +4,13 @@ error[E0107]: wrong number of type arguments: expected 2, found 1
 LL | async fn copy() -> Result<()>
    |                    ^^^^^^^^^^ expected 2 type arguments
 
-error: aborting due to previous error
+error[E0282]: type annotations needed
+  --> $DIR/issue-65159.rs:7:5
+   |
+LL |     Ok(())
+   |     ^^ cannot infer type for type parameter `E` declared on the enum `Result`
+
+error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0107`.
+Some errors have detailed explanations: E0107, E0282.
+For more information about an error, try `rustc --explain E0107`.