make ascribe_user_type a TypeOp

Projection types in user annotations may contain inference variables.
This makes the normalization depend on the unification with the actual
type and thus requires a separate TypeOp to track the obligations.
Otherwise simply calling `TypeChecker::normalize` would ICE with
"unexpected ambiguity"

9 files changed, 173 insertions, 17 deletions

diff --git a/src/test/ui/nll/ty-outlives/wf-unreachable.stderr b/src/test/ui/nll/ty-outlives/wf-unreachable.stderr
index a62157f44f5..da3bc208322 100644
--- a/src/test/ui/nll/ty-outlives/wf-unreachable.stderr
+++ b/src/test/ui/nll/ty-outlives/wf-unreachable.stderr
@@ -5,7 +5,7 @@ LL | fn uninit<'a>() {
    |           -- lifetime `'a` defined here
 LL |     return;
 LL |     let x: &'static &'a ();
-   |            ^^^^^^^^^^^^^^^ type annotation requires that `'a` must outlive `'static`
+   |            ^^^^^^^^^^^^^^^ requires that `'a` must outlive `'static`
 
 error: lifetime may not live long enough
   --> $DIR/wf-unreachable.rs:11:12
@@ -14,7 +14,7 @@ LL | fn var_type<'a>() {
    |             -- lifetime `'a` defined here
 LL |     return;
 LL |     let x: &'static &'a () = &&();
-   |            ^^^^^^^^^^^^^^^ type annotation requires that `'a` must outlive `'static`
+   |            ^^^^^^^^^^^^^^^ requires that `'a` must outlive `'static`
 
 error: lifetime may not live long enough
   --> $DIR/wf-unreachable.rs:15:12
@@ -22,7 +22,7 @@ error: lifetime may not live long enough
 LL | fn uninit_infer<'a>() {
    |                 -- lifetime `'a` defined here
 LL |     let x: &'static &'a _;
-   |            ^^^^^^^^^^^^^^ type annotation requires that `'a` must outlive `'static`
+   |            ^^^^^^^^^^^^^^ requires that `'a` must outlive `'static`
 
 error: lifetime may not live long enough
   --> $DIR/wf-unreachable.rs:21:12
@@ -31,7 +31,7 @@ LL | fn infer<'a>() {
    |          -- lifetime `'a` defined here
 LL |     return;
 LL |     let x: &'static &'a _ = &&();
-   |            ^^^^^^^^^^^^^^ type annotation requires that `'a` must outlive `'static`
+   |            ^^^^^^^^^^^^^^ requires that `'a` must outlive `'static`
 
 error: lifetime may not live long enough
   --> $DIR/wf-unreachable.rs:26:12
@@ -40,7 +40,7 @@ LL | fn uninit_no_var<'a>() {
    |                  -- lifetime `'a` defined here
 LL |     return;
 LL |     let _: &'static &'a ();
-   |            ^^^^^^^^^^^^^^^ type annotation requires that `'a` must outlive `'static`
+   |            ^^^^^^^^^^^^^^^ requires that `'a` must outlive `'static`
 
 error: lifetime may not live long enough
   --> $DIR/wf-unreachable.rs:31:12
@@ -49,7 +49,7 @@ LL | fn no_var<'a>() {
    |           -- lifetime `'a` defined here
 LL |     return;
 LL |     let _: &'static &'a () = &&();
-   |            ^^^^^^^^^^^^^^^ type annotation requires that `'a` must outlive `'static`
+   |            ^^^^^^^^^^^^^^^ requires that `'a` must outlive `'static`
 
 error: lifetime may not live long enough
   --> $DIR/wf-unreachable.rs:36:12
@@ -58,7 +58,7 @@ LL | fn infer_no_var<'a>() {
    |                 -- lifetime `'a` defined here
 LL |     return;
 LL |     let _: &'static &'a _ = &&();
-   |            ^^^^^^^^^^^^^^ type annotation requires that `'a` must outlive `'static`
+   |            ^^^^^^^^^^^^^^ requires that `'a` must outlive `'static`
 
 error: lifetime may not live long enough
   --> $DIR/wf-unreachable.rs:49:12
@@ -67,7 +67,7 @@ LL | fn required_substs<'a>() {
    |                    -- lifetime `'a` defined here
 LL |     return;
 LL |     let _: C<'static, 'a, _> = C((), &(), &());
-   |            ^^^^^^^^^^^^^^^^^ type annotation requires that `'a` must outlive `'static`
+   |            ^^^^^^^^^^^^^^^^^ requires that `'a` must outlive `'static`
 
 error: aborting due to 8 previous errors
 
diff --git a/src/test/ui/nll/user-annotations/closure-sig.rs b/src/test/ui/nll/user-annotations/closure-sig.rs
new file mode 100644
index 00000000000..4dbd3fd8d81
--- /dev/null
+++ b/src/test/ui/nll/user-annotations/closure-sig.rs
@@ -0,0 +1,15 @@
+// This test fails if #104478 is fixed before #104477.
+
+// check-pass
+
+struct Printer<'a, 'b>(&'a (), &'b ());
+
+impl Printer<'_, '_> {
+    fn test(self) {
+        let clo = |_: &'_ Self| {};
+        clo(&self);
+        clo(&self);
+    }
+}
+
+fn main() {}
diff --git a/src/test/ui/nll/user-annotations/normalization-infer.rs b/src/test/ui/nll/user-annotations/normalization-infer.rs
new file mode 100644
index 00000000000..8bfc272d4ba
--- /dev/null
+++ b/src/test/ui/nll/user-annotations/normalization-infer.rs
@@ -0,0 +1,40 @@
+// Annnotations may contain projection types with inference variables as input.
+// Make sure we don't get ambiguities when normalizing them.
+
+// check-fail
+
+// Single impl.
+fn test1<A, B, C, D>(a: A, b: B, c: C) {
+    trait Tr { type Ty; }
+    impl<T: 'static> Tr for (T,) { type Ty = T; }
+
+    let _: <(_,) as Tr>::Ty = a; //~ ERROR type `A`
+    Some::<<(_,) as Tr>::Ty>(b); //~ ERROR type `B`
+    || -> <(_,) as Tr>::Ty { c }; //~ ERROR type `C`
+    |d: <(_,) as Tr>::Ty| -> D { d }; //~ ERROR type `D`
+}
+
+
+// Two impls. The selected impl depends on the actual type.
+fn test2<A, B, C>(a: A, b: B, c: C) {
+    trait Tr { type Ty; }
+    impl<T: 'static> Tr for (u8, T) { type Ty = T; }
+    impl<T>          Tr for (i8, T) { type Ty = T; }
+    type Alias<X, Y> = (<(X, Y) as Tr>::Ty, X);
+
+    fn temp() -> String { todo!() }
+
+    // `u8` impl, requires static.
+    let _: Alias<_, _> = (a, 0u8); //~ ERROR type `A`
+    Some::<Alias<_, _>>((b, 0u8)); //~ ERROR type `B`
+    || -> Alias<_, _> { (c, 0u8) }; //~ ERROR type `C`
+
+    let _: Alias<_, _> = (&temp(), 0u8); //~ ERROR temporary value
+    Some::<Alias<_, _>>((&temp(), 0u8)); //~ ERROR temporary value
+
+    // `i8` impl, no region constraints.
+    let _: Alias<_, _> = (&temp(), 0i8);
+    Some::<Alias<_, _>>((&temp(), 0i8));
+}
+
+fn main() {}
diff --git a/src/test/ui/nll/user-annotations/normalization-infer.stderr b/src/test/ui/nll/user-annotations/normalization-infer.stderr
new file mode 100644
index 00000000000..12854ab6816
--- /dev/null
+++ b/src/test/ui/nll/user-annotations/normalization-infer.stderr
@@ -0,0 +1,101 @@
+error[E0310]: the parameter type `A` may not live long enough
+  --> $DIR/normalization-infer.rs:11:12
+   |
+LL |     let _: <(_,) as Tr>::Ty = a;
+   |            ^^^^^^^^^^^^^^^^ ...so that the type `A` will meet its required lifetime bounds
+   |
+help: consider adding an explicit lifetime bound...
+   |
+LL | fn test1<A: 'static, B, C, D>(a: A, b: B, c: C) {
+   |           +++++++++
+
+error[E0310]: the parameter type `B` may not live long enough
+  --> $DIR/normalization-infer.rs:12:5
+   |
+LL |     Some::<<(_,) as Tr>::Ty>(b);
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^ ...so that the type `B` will meet its required lifetime bounds
+   |
+help: consider adding an explicit lifetime bound...
+   |
+LL | fn test1<A, B: 'static, C, D>(a: A, b: B, c: C) {
+   |              +++++++++
+
+error[E0310]: the parameter type `C` may not live long enough
+  --> $DIR/normalization-infer.rs:13:11
+   |
+LL |     || -> <(_,) as Tr>::Ty { c };
+   |           ^^^^^^^^^^^^^^^^ ...so that the type `C` will meet its required lifetime bounds
+   |
+help: consider adding an explicit lifetime bound...
+   |
+LL | fn test1<A, B, C: 'static, D>(a: A, b: B, c: C) {
+   |                 +++++++++
+
+error[E0310]: the parameter type `D` may not live long enough
+  --> $DIR/normalization-infer.rs:14:6
+   |
+LL |     |d: <(_,) as Tr>::Ty| -> D { d };
+   |      ^ ...so that the type `D` will meet its required lifetime bounds
+   |
+help: consider adding an explicit lifetime bound...
+   |
+LL | fn test1<A, B, C, D: 'static>(a: A, b: B, c: C) {
+   |                    +++++++++
+
+error[E0310]: the parameter type `A` may not live long enough
+  --> $DIR/normalization-infer.rs:28:12
+   |
+LL |     let _: Alias<_, _> = (a, 0u8);
+   |            ^^^^^^^^^^^ ...so that the type `A` will meet its required lifetime bounds
+   |
+help: consider adding an explicit lifetime bound...
+   |
+LL | fn test2<A: 'static, B, C>(a: A, b: B, c: C) {
+   |           +++++++++
+
+error[E0310]: the parameter type `B` may not live long enough
+  --> $DIR/normalization-infer.rs:29:5
+   |
+LL |     Some::<Alias<_, _>>((b, 0u8));
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ...so that the type `B` will meet its required lifetime bounds
+   |
+help: consider adding an explicit lifetime bound...
+   |
+LL | fn test2<A, B: 'static, C>(a: A, b: B, c: C) {
+   |              +++++++++
+
+error[E0310]: the parameter type `C` may not live long enough
+  --> $DIR/normalization-infer.rs:30:11
+   |
+LL |     || -> Alias<_, _> { (c, 0u8) };
+   |           ^^^^^^^^^^^ ...so that the type `C` will meet its required lifetime bounds
+   |
+help: consider adding an explicit lifetime bound...
+   |
+LL | fn test2<A, B, C: 'static>(a: A, b: B, c: C) {
+   |                 +++++++++
+
+error[E0716]: temporary value dropped while borrowed
+  --> $DIR/normalization-infer.rs:32:28
+   |
+LL |     let _: Alias<_, _> = (&temp(), 0u8);
+   |            -----------     ^^^^^^ creates a temporary value which is freed while still in use
+   |            |
+   |            type annotation requires that borrow lasts for `'static`
+...
+LL | }
+   | - temporary value is freed at the end of this statement
+
+error[E0716]: temporary value dropped while borrowed
+  --> $DIR/normalization-infer.rs:33:27
+   |
+LL |     Some::<Alias<_, _>>((&temp(), 0u8));
+   |                         --^^^^^^------ - temporary value is freed at the end of this statement
+   |                         | |
+   |                         | creates a temporary value which is freed while still in use
+   |                         this usage requires that borrow lasts for `'static`
+
+error: aborting due to 9 previous errors
+
+Some errors have detailed explanations: E0310, E0716.
+For more information about an error, try `rustc --explain E0310`.
diff --git a/src/test/ui/regions/regions-assoc-type-in-supertrait-outlives-container.stderr b/src/test/ui/regions/regions-assoc-type-in-supertrait-outlives-container.stderr
index 87e33e1ccff..2a262520361 100644
--- a/src/test/ui/regions/regions-assoc-type-in-supertrait-outlives-container.stderr
+++ b/src/test/ui/regions/regions-assoc-type-in-supertrait-outlives-container.stderr
@@ -7,7 +7,7 @@ LL | fn with_assoc<'a,'b>() {
    |               lifetime `'a` defined here
 ...
 LL |     let _: &'a WithAssoc<TheType<'b>> = loop { };
-   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^ type annotation requires that `'b` must outlive `'a`
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^ requires that `'b` must outlive `'a`
    |
    = help: consider adding the following bound: `'b: 'a`
 
diff --git a/src/test/ui/regions/regions-free-region-ordering-caller.stderr b/src/test/ui/regions/regions-free-region-ordering-caller.stderr
index c79ed50c6a4..cdf70d2a5be 100644
--- a/src/test/ui/regions/regions-free-region-ordering-caller.stderr
+++ b/src/test/ui/regions/regions-free-region-ordering-caller.stderr
@@ -6,7 +6,7 @@ LL | fn call2<'a, 'b>(a: &'a usize, b: &'b usize) {
    |          |
    |          lifetime `'a` defined here
 LL |     let z: Option<&'b &'a usize> = None;
-   |            ^^^^^^^^^^^^^^^^^^^^^ type annotation requires that `'a` must outlive `'b`
+   |            ^^^^^^^^^^^^^^^^^^^^^ requires that `'a` must outlive `'b`
    |
    = help: consider adding the following bound: `'a: 'b`
 
@@ -19,7 +19,7 @@ LL | fn call3<'a, 'b>(a: &'a usize, b: &'b usize) {
    |          lifetime `'a` defined here
 LL |     let y: Paramd<'a> = Paramd { x: a };
 LL |     let z: Option<&'b Paramd<'a>> = None;
-   |            ^^^^^^^^^^^^^^^^^^^^^^ type annotation requires that `'a` must outlive `'b`
+   |            ^^^^^^^^^^^^^^^^^^^^^^ requires that `'a` must outlive `'b`
    |
    = help: consider adding the following bound: `'a: 'b`
 
@@ -31,7 +31,7 @@ LL | fn call4<'a, 'b>(a: &'a usize, b: &'b usize) {
    |          |
    |          lifetime `'a` defined here
 LL |     let z: Option<&'a &'b usize> = None;
-   |            ^^^^^^^^^^^^^^^^^^^^^ type annotation requires that `'b` must outlive `'a`
+   |            ^^^^^^^^^^^^^^^^^^^^^ requires that `'b` must outlive `'a`
    |
    = help: consider adding the following bound: `'b: 'a`
 
diff --git a/src/test/ui/regions/regions-outlives-projection-container-hrtb.stderr b/src/test/ui/regions/regions-outlives-projection-container-hrtb.stderr
index 187e9056e11..6a7c908fa40 100644
--- a/src/test/ui/regions/regions-outlives-projection-container-hrtb.stderr
+++ b/src/test/ui/regions/regions-outlives-projection-container-hrtb.stderr
@@ -7,7 +7,7 @@ LL | fn with_assoc<'a,'b>() {
    |               lifetime `'a` defined here
 ...
 LL |     let _: &'a WithHrAssoc<TheType<'b>> = loop { };
-   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type annotation requires that `'b` must outlive `'a`
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ requires that `'b` must outlive `'a`
    |
    = help: consider adding the following bound: `'b: 'a`
 
@@ -20,7 +20,7 @@ LL | fn with_assoc_sub<'a,'b>() {
    |                   lifetime `'a` defined here
 ...
 LL |     let _: &'a WithHrAssocSub<TheType<'b>> = loop { };
-   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type annotation requires that `'b` must outlive `'a`
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ requires that `'b` must outlive `'a`
    |
    = help: consider adding the following bound: `'b: 'a`
 
diff --git a/src/test/ui/regions/regions-outlives-projection-container-wc.stderr b/src/test/ui/regions/regions-outlives-projection-container-wc.stderr
index 4178e951c86..eba2a0d5853 100644
--- a/src/test/ui/regions/regions-outlives-projection-container-wc.stderr
+++ b/src/test/ui/regions/regions-outlives-projection-container-wc.stderr
@@ -7,7 +7,7 @@ LL | fn with_assoc<'a,'b>() {
    |               lifetime `'a` defined here
 ...
 LL |     let _: &'a WithAssoc<TheType<'b>> = loop { };
-   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^ type annotation requires that `'b` must outlive `'a`
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^ requires that `'b` must outlive `'a`
    |
    = help: consider adding the following bound: `'b: 'a`
 
diff --git a/src/test/ui/regions/regions-outlives-projection-container.stderr b/src/test/ui/regions/regions-outlives-projection-container.stderr
index 073a3190022..d20a2f06adf 100644
--- a/src/test/ui/regions/regions-outlives-projection-container.stderr
+++ b/src/test/ui/regions/regions-outlives-projection-container.stderr
@@ -7,7 +7,7 @@ LL | fn with_assoc<'a,'b>() {
    |               lifetime `'a` defined here
 ...
 LL |     let _x: &'a WithAssoc<TheType<'b>> = loop { };
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^ type annotation requires that `'b` must outlive `'a`
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^ requires that `'b` must outlive `'a`
    |
    = help: consider adding the following bound: `'b: 'a`
 
@@ -20,7 +20,7 @@ LL | fn without_assoc<'a,'b>() {
    |                  lifetime `'a` defined here
 ...
 LL |     let _x: &'a WithoutAssoc<TheType<'b>> = loop { };
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type annotation requires that `'b` must outlive `'a`
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ requires that `'b` must outlive `'a`
    |
    = help: consider adding the following bound: `'b: 'a`