Auto merge of #77069 - sexxi-goose:closure_print_2, r=nikomatsakis

pretty.rs: Update Closure and Generator print

More detailed outline: rust-lang/project-rfc-2229#17

Closes: rust-lang/project-rfc-2229#11

r? `@nikomatsakis`
cc `@eddyb` `@davidtwco` `@estebank`

compiler/rustc_middle/src/ty/print/pretty.rs

@@ -641,104 +641,86 @@ pub trait PrettyPrinter<'tcx>:
             }
             ty::Str => p!(write("str")),
             ty::Generator(did, substs, movability) => {
+                p!(write("["));
                 match movability {
-                    hir::Movability::Movable => p!(write("[generator")),
-                    hir::Movability::Static => p!(write("[static generator")),
+                    hir::Movability::Movable => {}
+                    hir::Movability::Static => p!(write("static ")),
                 }
 
-                // FIXME(eddyb) should use `def_span`.
-                if let Some(did) = did.as_local() {
-                    let hir_id = self.tcx().hir().local_def_id_to_hir_id(did);
-                    let span = self.tcx().hir().span(hir_id);
-                    p!(write("@{}", self.tcx().sess.source_map().span_to_string(span)));
-
-                    if substs.as_generator().is_valid() {
-                        let upvar_tys = substs.as_generator().upvar_tys();
-                        let mut sep = " ";
-                        for (&var_id, upvar_ty) in self
-                            .tcx()
-                            .upvars_mentioned(did)
-                            .as_ref()
-                            .iter()
-                            .flat_map(|v| v.keys())
-                            .zip(upvar_tys)
-                        {
-                            p!(write("{}{}:", sep, self.tcx().hir().name(var_id)), print(upvar_ty));
-                            sep = ", ";
-                        }
+                if !self.tcx().sess.verbose() {
+                    p!(write("generator"));
+                    // FIXME(eddyb) should use `def_span`.
+                    if let Some(did) = did.as_local() {
+                        let hir_id = self.tcx().hir().local_def_id_to_hir_id(did);
+                        let span = self.tcx().hir().span(hir_id);
+                        p!(write("@{}", self.tcx().sess.source_map().span_to_string(span)));
+                    } else {
+                        p!(write("@{}", self.tcx().def_path_str(did)));
                     }
                 } else {
-                    p!(write("@{}", self.tcx().def_path_str(did)));
-
+                    p!(print_def_path(did, substs));
                     if substs.as_generator().is_valid() {
-                        let upvar_tys = substs.as_generator().upvar_tys();
-                        let mut sep = " ";
-                        for (index, upvar_ty) in upvar_tys.enumerate() {
-                            p!(write("{}{}:", sep, index), print(upvar_ty));
-                            sep = ", ";
+                        // Search for the first inference variable
+                        p!(write(" upvar_tys=("));
+                        let mut uninferred_ty =
+                            substs.as_generator().upvar_tys().filter(|ty| ty.is_ty_infer());
+                        if uninferred_ty.next().is_some() {
+                            p!(write("unavailable"));
+                        } else {
+                            self = self.comma_sep(substs.as_generator().upvar_tys())?;
                         }
+                        p!(write(")"));
                     }
                 }
 
                 if substs.as_generator().is_valid() {
                     p!(write(" "), print(substs.as_generator().witness()));
                 }
 
-                p!(write("]"))
+                p!(write("]"));
             }
             ty::GeneratorWitness(types) => {
                 p!(in_binder(&types));
             }
             ty::Closure(did, substs) => {
-                p!(write("[closure"));
-
-                // FIXME(eddyb) should use `def_span`.
-                if let Some(did) = did.as_local() {
-                    let hir_id = self.tcx().hir().local_def_id_to_hir_id(did);
-                    if self.tcx().sess.opts.debugging_opts.span_free_formats {
-                        p!(write("@"), print_def_path(did.to_def_id(), substs));
-                    } else {
-                        let span = self.tcx().hir().span(hir_id);
-                        p!(write("@{}", self.tcx().sess.source_map().span_to_string(span)));
-                    }
-
-                    if substs.as_closure().is_valid() {
-                        let upvar_tys = substs.as_closure().upvar_tys();
-                        let mut sep = " ";
-                        for (&var_id, upvar_ty) in self
-                            .tcx()
-                            .upvars_mentioned(did)
-                            .as_ref()
-                            .iter()
-                            .flat_map(|v| v.keys())
-                            .zip(upvar_tys)
-                        {
-                            p!(write("{}{}:", sep, self.tcx().hir().name(var_id)), print(upvar_ty));
-                            sep = ", ";
+                p!(write("["));
+                if !self.tcx().sess.verbose() {
+                    p!(write("closure"));
+                    // FIXME(eddyb) should use `def_span`.
+                    if let Some(did) = did.as_local() {
+                        let hir_id = self.tcx().hir().local_def_id_to_hir_id(did);
+                        if self.tcx().sess.opts.debugging_opts.span_free_formats {
+                            p!(write("@"), print_def_path(did.to_def_id(), substs));
+                        } else {
+                            let span = self.tcx().hir().span(hir_id);
+                            p!(write("@{}", self.tcx().sess.source_map().span_to_string(span)));
                         }
+                    } else {
+                        p!(write("@{}", self.tcx().def_path_str(did)));
                     }
                 } else {
-                    p!(write("@{}", self.tcx().def_path_str(did)));
-
+                    p!(print_def_path(did, substs));
                     if substs.as_closure().is_valid() {
-                        let upvar_tys = substs.as_closure().upvar_tys();
-                        let mut sep = " ";
-                        for (index, upvar_ty) in upvar_tys.enumerate() {
-                            p!(write("{}{}:", sep, index), print(upvar_ty));
-                            sep = ", ";
+                        // Search for the first inference variable
+                        let mut uninferred_ty =
+                            substs.as_closure().upvar_tys().filter(|ty| ty.is_ty_infer());
+                        if uninferred_ty.next().is_some() {
+                            // If the upvar substs contain an inference variable we haven't
+                            // finished capture analysis.
+                            p!(write(" closure_substs=(unavailable)"));
+                        } else {
+                            p!(write(" closure_kind_ty="), print(substs.as_closure().kind_ty()));
+                            p!(
+                                write(" closure_sig_as_fn_ptr_ty="),
+                                print(substs.as_closure().sig_as_fn_ptr_ty())
+                            );
+                            p!(write(" upvar_tys=("));
+                            self = self.comma_sep(substs.as_closure().upvar_tys())?;
+                            p!(write(")"));
                         }
                     }
                 }
-
-                if self.tcx().sess.verbose() && substs.as_closure().is_valid() {
-                    p!(write(" closure_kind_ty="), print(substs.as_closure().kind_ty()));
-                    p!(
-                        write(" closure_sig_as_fn_ptr_ty="),
-                        print(substs.as_closure().sig_as_fn_ptr_ty())
-                    );
-                }
-
-                p!(write("]"))
+                p!(write("]"));
             }
             ty::Array(ty, sz) => {
                 p!(write("["), print(ty), write("; "));

src/test/mir-opt/inline/inline_closure_captures.foo.Inline.after.mir

@@ -4,10 +4,10 @@ fn foo(_1: T, _2: i32) -> (i32, T) {
     debug t => _1;                       // in scope 0 at $DIR/inline-closure-captures.rs:10:17: 10:18
     debug q => _2;                       // in scope 0 at $DIR/inline-closure-captures.rs:10:23: 10:24
     let mut _0: (i32, T);                // return place in scope 0 at $DIR/inline-closure-captures.rs:10:34: 10:42
-    let _3: [closure@foo<T>::{closure#0} q:&i32, t:&T]; // in scope 0 at $DIR/inline-closure-captures.rs:11:9: 11:10
+    let _3: [closure@foo<T>::{closure#0}]; // in scope 0 at $DIR/inline-closure-captures.rs:11:9: 11:10
     let mut _4: &i32;                    // in scope 0 at $DIR/inline-closure-captures.rs:11:13: 11:24
     let mut _5: &T;                      // in scope 0 at $DIR/inline-closure-captures.rs:11:13: 11:24
-    let mut _6: &[closure@foo<T>::{closure#0} q:&i32, t:&T]; // in scope 0 at $DIR/inline-closure-captures.rs:12:5: 12:6
+    let mut _6: &[closure@foo<T>::{closure#0}]; // in scope 0 at $DIR/inline-closure-captures.rs:12:5: 12:6
     let mut _7: (i32,);                  // in scope 0 at $DIR/inline-closure-captures.rs:12:5: 12:9
     let mut _8: i32;                     // in scope 0 at $DIR/inline-closure-captures.rs:12:7: 12:8
     let mut _10: i32;                    // in scope 0 at $DIR/inline-closure-captures.rs:12:5: 12:9

src/test/ui/async-await/issue-68112.stderr

@@ -41,8 +41,8 @@ LL |     require_send(send_fut);
    |
    = help: the trait `Sync` is not implemented for `RefCell<i32>`
    = note: required because of the requirements on the impl of `Send` for `Arc<RefCell<i32>>`
-   = note: required because it appears within the type `[static generator@$DIR/issue-68112.rs:47:31: 47:36 t:Arc<RefCell<i32>> {}]`
-   = note: required because it appears within the type `from_generator::GenFuture<[static generator@$DIR/issue-68112.rs:47:31: 47:36 t:Arc<RefCell<i32>> {}]>`
+   = note: required because it appears within the type `[static generator@$DIR/issue-68112.rs:47:31: 47:36 {}]`
+   = note: required because it appears within the type `from_generator::GenFuture<[static generator@$DIR/issue-68112.rs:47:31: 47:36 {}]>`
    = note: required because it appears within the type `impl Future`
    = note: required because it appears within the type `impl Future`
    = note: required because it appears within the type `impl Future`

src/test/ui/block-result/issue-20862.stderr

@@ -7,7 +7,7 @@ LL |     |y| x + y
    |     ^^^^^^^^^ expected `()`, found closure
    |
    = note: expected unit type `()`
-                found closure `[closure@$DIR/issue-20862.rs:2:5: 2:14 x:_]`
+                found closure `[closure@$DIR/issue-20862.rs:2:5: 2:14]`
 
 error[E0618]: expected function, found `()`
   --> $DIR/issue-20862.rs:7:13

src/test/ui/borrowck/issue-53432-nested-closure-outlives-borrowed-value.stderr

@@ -4,7 +4,7 @@ error: lifetime may not live long enough
 LL |     let _action = move || {
    |                   -------
    |                   |     |
-   |                   |     return type of closure is [closure@$DIR/issue-53432-nested-closure-outlives-borrowed-value.rs:4:9: 4:15 f:&'2 [closure@$DIR/issue-53432-nested-closure-outlives-borrowed-value.rs:2:13: 2:23]]
+   |                   |     return type of closure is [closure@$DIR/issue-53432-nested-closure-outlives-borrowed-value.rs:4:9: 4:15]
    |                   lifetime `'1` represents this closure's body
 LL |         || f() // The `nested` closure
    |         ^^^^^^ returning this value requires that `'1` must outlive `'2`

src/test/ui/closures/closure-move-sync.stderr

@@ -11,7 +11,7 @@ LL |     F: Send + 'static,
    |
    = help: the trait `Sync` is not implemented for `std::sync::mpsc::Receiver<()>`
    = note: required because of the requirements on the impl of `Send` for `&std::sync::mpsc::Receiver<()>`
-   = note: required because it appears within the type `[closure@$DIR/closure-move-sync.rs:6:27: 9:6 recv:&std::sync::mpsc::Receiver<()>]`
+   = note: required because it appears within the type `[closure@$DIR/closure-move-sync.rs:6:27: 9:6]`
 
 error[E0277]: `Sender<()>` cannot be shared between threads safely
   --> $DIR/closure-move-sync.rs:18:5
@@ -26,7 +26,7 @@ LL |     F: Send + 'static,
    |
    = help: the trait `Sync` is not implemented for `Sender<()>`
    = note: required because of the requirements on the impl of `Send` for `&Sender<()>`
-   = note: required because it appears within the type `[closure@$DIR/closure-move-sync.rs:18:19: 18:42 tx:&Sender<()>]`
+   = note: required because it appears within the type `[closure@$DIR/closure-move-sync.rs:18:19: 18:42]`
 
 error: aborting due to 2 previous errors
 

src/test/ui/closures/closure-no-fn-1.stderr

@@ -7,7 +7,7 @@ LL |     let foo: fn(u8) -> u8 = |v: u8| { a += v; a };
    |              expected due to this
    |
    = note: expected fn pointer `fn(u8) -> u8`
-                 found closure `[closure@$DIR/closure-no-fn-1.rs:6:29: 6:50 a:_]`
+                 found closure `[closure@$DIR/closure-no-fn-1.rs:6:29: 6:50]`
 
 error: aborting due to previous error
 

src/test/ui/closures/closure-no-fn-2.stderr

@@ -7,7 +7,7 @@ LL |     let bar: fn() -> u8 = || { b };
    |              expected due to this
    |
    = note: expected fn pointer `fn() -> u8`
-                 found closure `[closure@$DIR/closure-no-fn-2.rs:6:27: 6:35 b:_]`
+                 found closure `[closure@$DIR/closure-no-fn-2.rs:6:27: 6:35]`
 
 error: aborting due to previous error
 

src/test/ui/closures/closure-no-fn-3.stderr

@@ -1,4 +1,4 @@
-error[E0605]: non-primitive cast: `[closure@$DIR/closure-no-fn-3.rs:6:27: 6:37 b:_]` as `fn() -> u8`
+error[E0605]: non-primitive cast: `[closure@$DIR/closure-no-fn-3.rs:6:27: 6:37]` as `fn() -> u8`
   --> $DIR/closure-no-fn-3.rs:6:27
    |
 LL |     let baz: fn() -> u8 = (|| { b }) as fn() -> u8;

src/test/ui/closures/closure-reform-bad.stderr

@@ -7,7 +7,7 @@ LL |     call_bare(f)
    |               ^ expected fn pointer, found closure
    |
    = note: expected fn pointer `for<'r> fn(&'r str)`
-                 found closure `[closure@$DIR/closure-reform-bad.rs:10:13: 10:50 string:_]`
+                 found closure `[closure@$DIR/closure-reform-bad.rs:10:13: 10:50]`
 
 error: aborting due to previous error
 

src/test/ui/closures/closure_cap_coerce_many_fail.stderr

@@ -12,7 +12,7 @@ LL | |     };
    | |_____- `match` arms have incompatible types
    |
    = note: expected type `fn(i32, i32) -> i32 {add}`
-           found closure `[closure@$DIR/closure_cap_coerce_many_fail.rs:9:16: 9:43 cap:_]`
+           found closure `[closure@$DIR/closure_cap_coerce_many_fail.rs:9:16: 9:43]`
 
 error[E0308]: `match` arms have incompatible types
   --> $DIR/closure_cap_coerce_many_fail.rs:18:16
@@ -28,7 +28,7 @@ LL | |     };
    | |_____- `match` arms have incompatible types
    |
    = note: expected type `[closure@$DIR/closure_cap_coerce_many_fail.rs:17:16: 17:37]`
-           found closure `[closure@$DIR/closure_cap_coerce_many_fail.rs:18:16: 18:43 cap:_]`
+           found closure `[closure@$DIR/closure_cap_coerce_many_fail.rs:18:16: 18:43]`
    = note: no two closures, even if identical, have the same type
    = help: consider boxing your closure and/or using it as a trait object
 
@@ -38,14 +38,14 @@ error[E0308]: `match` arms have incompatible types
 LL |       let _ = match "+" {
    |  _____________-
 LL | |         "+" => |a, b| (a + b + cap) as i32,
-   | |                --------------------------- this is found to be of type `[closure@$DIR/closure_cap_coerce_many_fail.rs:26:16: 26:43 cap:_]`
+   | |                --------------------------- this is found to be of type `[closure@$DIR/closure_cap_coerce_many_fail.rs:26:16: 26:43]`
 LL | |         "-" => |a, b| (a - b) as i32,
    | |                ^^^^^^^^^^^^^^^^^^^^^ expected closure, found a different closure
 LL | |         _ => unimplemented!(),
 LL | |     };
    | |_____- `match` arms have incompatible types
    |
-   = note: expected type `[closure@$DIR/closure_cap_coerce_many_fail.rs:26:16: 26:43 cap:_]`
+   = note: expected type `[closure@$DIR/closure_cap_coerce_many_fail.rs:26:16: 26:43]`
            found closure `[closure@$DIR/closure_cap_coerce_many_fail.rs:27:16: 27:37]`
    = note: no two closures, even if identical, have the same type
    = help: consider boxing your closure and/or using it as a trait object
@@ -56,15 +56,15 @@ error[E0308]: `match` arms have incompatible types
 LL |       let _ = match "+" {
    |  _____________-
 LL | |         "+" => |a, b| (a + b + cap) as i32,
-   | |                --------------------------- this is found to be of type `[closure@$DIR/closure_cap_coerce_many_fail.rs:34:16: 34:43 cap:_]`
+   | |                --------------------------- this is found to be of type `[closure@$DIR/closure_cap_coerce_many_fail.rs:34:16: 34:43]`
 LL | |         "-" => |a, b| (a - b + cap) as i32,
    | |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected closure, found a different closure
 LL | |         _ => unimplemented!(),
 LL | |     };
    | |_____- `match` arms have incompatible types
    |
-   = note: expected type `[closure@$DIR/closure_cap_coerce_many_fail.rs:34:16: 34:43 cap:_]`
-           found closure `[closure@$DIR/closure_cap_coerce_many_fail.rs:35:16: 35:43 cap:_]`
+   = note: expected type `[closure@$DIR/closure_cap_coerce_many_fail.rs:34:16: 34:43]`
+           found closure `[closure@$DIR/closure_cap_coerce_many_fail.rs:35:16: 35:43]`
    = note: no two closures, even if identical, have the same type
    = help: consider boxing your closure and/or using it as a trait object
 

src/test/ui/closures/print/closure-print-generic-1.rs

@@ -0,0 +1,23 @@
+fn to_fn_once<F: FnOnce()>(f: F) -> F {
+    f
+}
+
+fn f<T: std::fmt::Display>(y: T) {
+    struct Foo<U: std::fmt::Display> {
+        x: U,
+    };
+
+    let foo = Foo { x: "x" };
+
+    let c = to_fn_once(move || {
+        println!("{} {}", foo.x, y);
+    });
+
+    c();
+    c();
+    //~^ ERROR use of moved value
+}
+
+fn main() {
+    f("S");
+}

src/test/ui/closures/print/closure-print-generic-1.stderr

@@ -0,0 +1,20 @@
+error[E0382]: use of moved value: `c`
+  --> $DIR/closure-print-generic-1.rs:17:5
+   |
+LL |     let c = to_fn_once(move || {
+   |         - move occurs because `c` has type `[closure@$DIR/closure-print-generic-1.rs:12:24: 14:6]`, which does not implement the `Copy` trait
+...
+LL |     c();
+   |     --- `c` moved due to this call
+LL |     c();
+   |     ^ value used here after move
+   |
+note: this value implements `FnOnce`, which causes it to be moved when called
+  --> $DIR/closure-print-generic-1.rs:16:5
+   |
+LL |     c();
+   |     ^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0382`.

src/test/ui/closures/print/closure-print-generic-2.rs

@@ -0,0 +1,13 @@
+mod mod1 {
+    pub fn f<T: std::fmt::Display>(t: T) {
+        let x = 20;
+
+        let c = || println!("{} {}", t, x);
+        let c1: () = c;
+        //~^ ERROR mismatched types
+    }
+}
+
+fn main() {
+    mod1::f(5i32);
+}

src/test/ui/closures/print/closure-print-generic-2.stderr

@@ -0,0 +1,20 @@
+error[E0308]: mismatched types
+  --> $DIR/closure-print-generic-2.rs:6:22
+   |
+LL |         let c = || println!("{} {}", t, x);
+   |                 -------------------------- the found closure
+LL |         let c1: () = c;
+   |                 --   ^ expected `()`, found closure
+   |                 |
+   |                 expected due to this
+   |
+   = note: expected unit type `()`
+                found closure `[closure@$DIR/closure-print-generic-2.rs:5:17: 5:43]`
+help: use parentheses to call this closure
+   |
+LL |         let c1: () = c();
+   |                       ^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.