Rollup merge of #65777 - matthewjasper:allow-impl-trait-expansion, r=davidtwco

Don't ICE for completely unexpandable `impl Trait` types

Save the resolution of these types (to themselves) to the typeck tables so that they will eventually reach E0720.

closes #65561

6 files changed, 42 insertions, 24 deletions

diff --git a/src/test/ui/impl-trait/recursive-impl-trait-type-direct.rs b/src/test/ui/impl-trait/recursive-impl-trait-type-direct.rs
new file mode 100644
index 00000000000..2b4f5e0975a
--- /dev/null
+++ b/src/test/ui/impl-trait/recursive-impl-trait-type-direct.rs
@@ -0,0 +1,7 @@
+// Test that an `impl Trait` type that expands to itself is an error.
+
+fn test() -> impl Sized { //~ ERROR E0720
+    test()
+}
+
+fn main() {}
diff --git a/src/test/ui/impl-trait/recursive-impl-trait-type-direct.stderr b/src/test/ui/impl-trait/recursive-impl-trait-type-direct.stderr
new file mode 100644
index 00000000000..1b5dbd814a4
--- /dev/null
+++ b/src/test/ui/impl-trait/recursive-impl-trait-type-direct.stderr
@@ -0,0 +1,11 @@
+error[E0720]: opaque type expands to a recursive type
+  --> $DIR/recursive-impl-trait-type-direct.rs:3:14
+   |
+LL | fn test() -> impl Sized {
+   |              ^^^^^^^^^^ expands to a recursive type
+   |
+   = note: type resolves to itself
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0720`.
diff --git a/src/test/ui/impl-trait/recursive-impl-trait-type.rs b/src/test/ui/impl-trait/recursive-impl-trait-type-indirect.rs
index 2428b560b70..2428b560b70 100644
--- a/src/test/ui/impl-trait/recursive-impl-trait-type.rs
+++ b/src/test/ui/impl-trait/recursive-impl-trait-type-indirect.rs
diff --git a/src/test/ui/impl-trait/recursive-impl-trait-type.stderr b/src/test/ui/impl-trait/recursive-impl-trait-type-indirect.stderr
index 324607117dc..b7ba0d6ab17 100644
--- a/src/test/ui/impl-trait/recursive-impl-trait-type.stderr
+++ b/src/test/ui/impl-trait/recursive-impl-trait-type-indirect.stderr
@@ -1,5 +1,5 @@
 error[E0720]: opaque type expands to a recursive type
-  --> $DIR/recursive-impl-trait-type.rs:6:22
+  --> $DIR/recursive-impl-trait-type-indirect.rs:6:22
    |
 LL | fn option(i: i32) -> impl Sized {
    |                      ^^^^^^^^^^ expands to a recursive type
@@ -7,7 +7,7 @@ LL | fn option(i: i32) -> impl Sized {
    = note: expanded type is `std::option::Option<(impl Sized, i32)>`
 
 error[E0720]: opaque type expands to a recursive type
-  --> $DIR/recursive-impl-trait-type.rs:14:15
+  --> $DIR/recursive-impl-trait-type-indirect.rs:14:15
    |
 LL | fn tuple() -> impl Sized {
    |               ^^^^^^^^^^ expands to a recursive type
@@ -15,7 +15,7 @@ LL | fn tuple() -> impl Sized {
    = note: expanded type is `(impl Sized,)`
 
 error[E0720]: opaque type expands to a recursive type
-  --> $DIR/recursive-impl-trait-type.rs:18:15
+  --> $DIR/recursive-impl-trait-type-indirect.rs:18:15
    |
 LL | fn array() -> impl Sized {
    |               ^^^^^^^^^^ expands to a recursive type
@@ -23,7 +23,7 @@ LL | fn array() -> impl Sized {
    = note: expanded type is `[impl Sized; 1]`
 
 error[E0720]: opaque type expands to a recursive type
-  --> $DIR/recursive-impl-trait-type.rs:22:13
+  --> $DIR/recursive-impl-trait-type-indirect.rs:22:13
    |
 LL | fn ptr() -> impl Sized {
    |             ^^^^^^^^^^ expands to a recursive type
@@ -31,7 +31,7 @@ LL | fn ptr() -> impl Sized {
    = note: expanded type is `*const impl Sized`
 
 error[E0720]: opaque type expands to a recursive type
-  --> $DIR/recursive-impl-trait-type.rs:26:16
+  --> $DIR/recursive-impl-trait-type-indirect.rs:26:16
    |
 LL | fn fn_ptr() -> impl Sized {
    |                ^^^^^^^^^^ expands to a recursive type
@@ -39,47 +39,47 @@ LL | fn fn_ptr() -> impl Sized {
    = note: expanded type is `fn() -> impl Sized`
 
 error[E0720]: opaque type expands to a recursive type
-  --> $DIR/recursive-impl-trait-type.rs:30:25
+  --> $DIR/recursive-impl-trait-type-indirect.rs:30:25
    |
 LL | fn closure_capture() -> impl Sized {
    |                         ^^^^^^^^^^ expands to a recursive type
    |
-   = note: expanded type is `[closure@$DIR/recursive-impl-trait-type.rs:32:5: 32:19 x:impl Sized]`
+   = note: expanded type is `[closure@$DIR/recursive-impl-trait-type-indirect.rs:32:5: 32:19 x:impl Sized]`
 
 error[E0720]: opaque type expands to a recursive type
-  --> $DIR/recursive-impl-trait-type.rs:35:29
+  --> $DIR/recursive-impl-trait-type-indirect.rs:35:29
    |
 LL | fn closure_ref_capture() -> impl Sized {
    |                             ^^^^^^^^^^ expands to a recursive type
    |
-   = note: expanded type is `[closure@$DIR/recursive-impl-trait-type.rs:37:5: 37:20 x:impl Sized]`
+   = note: expanded type is `[closure@$DIR/recursive-impl-trait-type-indirect.rs:37:5: 37:20 x:impl Sized]`
 
 error[E0720]: opaque type expands to a recursive type
-  --> $DIR/recursive-impl-trait-type.rs:40:21
+  --> $DIR/recursive-impl-trait-type-indirect.rs:40:21
    |
 LL | fn closure_sig() -> impl Sized {
    |                     ^^^^^^^^^^ expands to a recursive type
    |
-   = note: expanded type is `[closure@$DIR/recursive-impl-trait-type.rs:41:5: 41:21]`
+   = note: expanded type is `[closure@$DIR/recursive-impl-trait-type-indirect.rs:41:5: 41:21]`
 
 error[E0720]: opaque type expands to a recursive type
-  --> $DIR/recursive-impl-trait-type.rs:44:23
+  --> $DIR/recursive-impl-trait-type-indirect.rs:44:23
    |
 LL | fn generator_sig() -> impl Sized {
    |                       ^^^^^^^^^^ expands to a recursive type
    |
-   = note: expanded type is `[closure@$DIR/recursive-impl-trait-type.rs:45:5: 45:23]`
+   = note: expanded type is `[closure@$DIR/recursive-impl-trait-type-indirect.rs:45:5: 45:23]`
 
 error[E0720]: opaque type expands to a recursive type
-  --> $DIR/recursive-impl-trait-type.rs:48:27
+  --> $DIR/recursive-impl-trait-type-indirect.rs:48:27
    |
 LL | fn generator_capture() -> impl Sized {
    |                           ^^^^^^^^^^ expands to a recursive type
    |
-   = note: expanded type is `[generator@$DIR/recursive-impl-trait-type.rs:50:5: 50:26 x:impl Sized {()}]`
+   = note: expanded type is `[generator@$DIR/recursive-impl-trait-type-indirect.rs:50:5: 50:26 x:impl Sized {()}]`
 
 error[E0720]: opaque type expands to a recursive type
-  --> $DIR/recursive-impl-trait-type.rs:53:26
+  --> $DIR/recursive-impl-trait-type-indirect.rs:53:26
    |
 LL | fn substs_change<T>() -> impl Sized {
    |                          ^^^^^^^^^^ expands to a recursive type
@@ -87,15 +87,15 @@ LL | fn substs_change<T>() -> impl Sized {
    = note: expanded type is `(impl Sized,)`
 
 error[E0720]: opaque type expands to a recursive type
-  --> $DIR/recursive-impl-trait-type.rs:57:24
+  --> $DIR/recursive-impl-trait-type-indirect.rs:57:24
    |
 LL | fn generator_hold() -> impl Sized {
    |                        ^^^^^^^^^^ expands to a recursive type
    |
-   = note: expanded type is `[generator@$DIR/recursive-impl-trait-type.rs:58:5: 62:6 {impl Sized, ()}]`
+   = note: expanded type is `[generator@$DIR/recursive-impl-trait-type-indirect.rs:58:5: 62:6 {impl Sized, ()}]`
 
 error[E0720]: opaque type expands to a recursive type
-  --> $DIR/recursive-impl-trait-type.rs:69:26
+  --> $DIR/recursive-impl-trait-type-indirect.rs:69:26
    |
 LL | fn mutual_recursion() -> impl Sync {
    |                          ^^^^^^^^^ expands to a recursive type
@@ -103,7 +103,7 @@ LL | fn mutual_recursion() -> impl Sync {
    = note: type resolves to itself
 
 error[E0720]: opaque type expands to a recursive type
-  --> $DIR/recursive-impl-trait-type.rs:73:28
+  --> $DIR/recursive-impl-trait-type-indirect.rs:73:28
    |
 LL | fn mutual_recursion_b() -> impl Sized {
    |                            ^^^^^^^^^^ expands to a recursive type
diff --git a/src/test/ui/impl-trait/recursive-impl-trait-type--through-non-recursize.rs b/src/test/ui/impl-trait/recursive-impl-trait-type-through-non-recursive.rs
index cfd9c0ec5b4..cfd9c0ec5b4 100644
--- a/src/test/ui/impl-trait/recursive-impl-trait-type--through-non-recursize.rs
+++ b/src/test/ui/impl-trait/recursive-impl-trait-type-through-non-recursive.rs
diff --git a/src/test/ui/impl-trait/recursive-impl-trait-type--through-non-recursize.stderr b/src/test/ui/impl-trait/recursive-impl-trait-type-through-non-recursive.stderr
index 7572c6c1bf0..73c12f6137d 100644
--- a/src/test/ui/impl-trait/recursive-impl-trait-type--through-non-recursize.stderr
+++ b/src/test/ui/impl-trait/recursive-impl-trait-type-through-non-recursive.stderr
@@ -1,5 +1,5 @@
 error[E0720]: opaque type expands to a recursive type
-  --> $DIR/recursive-impl-trait-type--through-non-recursize.rs:7:22
+  --> $DIR/recursive-impl-trait-type-through-non-recursive.rs:7:22
    |
 LL | fn recursive_id() -> impl Sized {
    |                      ^^^^^^^^^^ expands to a recursive type
@@ -7,7 +7,7 @@ LL | fn recursive_id() -> impl Sized {
    = note: type resolves to itself
 
 error[E0720]: opaque type expands to a recursive type
-  --> $DIR/recursive-impl-trait-type--through-non-recursize.rs:11:23
+  --> $DIR/recursive-impl-trait-type-through-non-recursive.rs:11:23
    |
 LL | fn recursive_id2() -> impl Sized {
    |                       ^^^^^^^^^^ expands to a recursive type
@@ -15,7 +15,7 @@ LL | fn recursive_id2() -> impl Sized {
    = note: type resolves to itself
 
 error[E0720]: opaque type expands to a recursive type
-  --> $DIR/recursive-impl-trait-type--through-non-recursize.rs:17:24
+  --> $DIR/recursive-impl-trait-type-through-non-recursive.rs:17:24
    |
 LL | fn recursive_wrap() -> impl Sized {
    |                        ^^^^^^^^^^ expands to a recursive type
@@ -23,7 +23,7 @@ LL | fn recursive_wrap() -> impl Sized {
    = note: expanded type is `((impl Sized,),)`
 
 error[E0720]: opaque type expands to a recursive type
-  --> $DIR/recursive-impl-trait-type--through-non-recursize.rs:21:25
+  --> $DIR/recursive-impl-trait-type-through-non-recursive.rs:21:25
    |
 LL | fn recursive_wrap2() -> impl Sized {
    |                         ^^^^^^^^^^ expands to a recursive type