Call type_of for opaque types later in compilation

This ensures that various wf checks have already been done before we
typeck item bodies.

Author: matthewjasper

compiler/rustc_typeck/src/check/check.rs

@@ -385,6 +385,7 @@ pub(super) fn check_opaque<'tcx>(
     origin: &hir::OpaqueTyOrigin,
 ) {
     check_opaque_for_inheriting_lifetimes(tcx, def_id, span);
+    tcx.ensure().type_of(def_id);
     check_opaque_for_cycles(tcx, def_id, substs, span, origin);
 }
 

compiler/rustc_typeck/src/collect.rs

@@ -693,8 +693,14 @@ fn convert_item(tcx: TyCtxt<'_>, item_id: hir::HirId) {
         // Desugared from `impl Trait`, so visited by the function's return type.
         hir::ItemKind::OpaqueTy(hir::OpaqueTy { impl_trait_fn: Some(_), .. }) => {}
 
-        hir::ItemKind::OpaqueTy(..)
-        | hir::ItemKind::TyAlias(..)
+        // Don't call `type_of` on opaque types, since that depends on type
+        // checking function bodies. `check_item_type` ensures that it's called
+        // instead.
+        hir::ItemKind::OpaqueTy(..) => {
+            tcx.ensure().generics_of(def_id);
+            tcx.ensure().predicates_of(def_id);
+        }
+        hir::ItemKind::TyAlias(..)
         | hir::ItemKind::Static(..)
         | hir::ItemKind::Const(..)
         | hir::ItemKind::Fn(..) => {

compiler/rustc_typeck/src/lib.rs

@@ -360,7 +360,7 @@ pub fn check_crate(tcx: TyCtxt<'_>) -> Result<(), ErrorReported> {
 
     // this ensures that later parts of type checking can assume that items
     // have valid types and not error
-    // FIXME(matthewjasper) We shouldn't need to do this.
+    // FIXME(matthewjasper) We shouldn't need to use `track_errors`.
     tcx.sess.track_errors(|| {
         tcx.sess.time("type_collecting", || {
             for &module in tcx.hir().krate().modules.keys() {

src/test/ui/associated-type-bounds/duplicate.rs

@@ -60,11 +60,8 @@ fn FW3<T>() where T: Iterator<Item: 'static, Item: 'static> {}
 //~^ ERROR the value of the associated type `Item` (from trait `Iterator`) is already specified [E0719]
 
 fn FRPIT1() -> impl Iterator<Item: Copy, Item: Send> { iter::empty() }
-//~^ ERROR the value of the associated type `Item` (from trait `Iterator`) is already specified [E0719]
 fn FRPIT2() -> impl Iterator<Item: Copy, Item: Copy> { iter::empty() }
-//~^ ERROR the value of the associated type `Item` (from trait `Iterator`) is already specified [E0719]
 fn FRPIT3() -> impl Iterator<Item: 'static, Item: 'static> { iter::empty() }
-//~^ ERROR the value of the associated type `Item` (from trait `Iterator`) is already specified [E0719]
 fn FAPIT1(_: impl Iterator<Item: Copy, Item: Send>) {}
 //~^ ERROR the value of the associated type `Item` (from trait `Iterator`) is already specified [E0719]
 fn FAPIT2(_: impl Iterator<Item: Copy, Item: Copy>) {}
@@ -107,28 +104,16 @@ type TAW3<T> where T: Iterator<Item: 'static, Item: 'static> = T;
 
 type ETAI1<T: Iterator<Item: Copy, Item: Send>> = impl Copy;
 //~^ ERROR the value of the associated type `Item` (from trait `Iterator`) is already specified [E0719]
-//~| ERROR could not find defining uses
 type ETAI2<T: Iterator<Item: Copy, Item: Copy>> = impl Copy;
 //~^ ERROR the value of the associated type `Item` (from trait `Iterator`) is already specified [E0719]
-//~| ERROR could not find defining uses
 type ETAI3<T: Iterator<Item: 'static, Item: 'static>> = impl Copy;
 //~^ ERROR the value of the associated type `Item` (from trait `Iterator`) is already specified [E0719]
-//~| ERROR could not find defining uses
 type ETAI4 = impl Iterator<Item: Copy, Item: Send>;
 //~^ ERROR the value of the associated type `Item` (from trait `Iterator`) is already specified [E0719]
-//~| ERROR could not find defining uses
-//~| ERROR could not find defining uses
-//~| ERROR could not find defining uses
 type ETAI5 = impl Iterator<Item: Copy, Item: Copy>;
 //~^ ERROR the value of the associated type `Item` (from trait `Iterator`) is already specified [E0719]
-//~| ERROR could not find defining uses
-//~| ERROR could not find defining uses
-//~| ERROR could not find defining uses
 type ETAI6 = impl Iterator<Item: 'static, Item: 'static>;
 //~^ ERROR the value of the associated type `Item` (from trait `Iterator`) is already specified [E0719]
-//~| ERROR could not find defining uses
-//~| ERROR could not find defining uses
-//~| ERROR could not find defining uses
 
 trait TRI1<T: Iterator<Item: Copy, Item: Send>> {}
 //~^ ERROR the value of the associated type `Item` (from trait `Iterator`) is already specified [E0719]
@@ -166,15 +151,9 @@ trait TRA3 { type A: Iterator<Item: 'static, Item: 'static>; }
 
 type TADyn1 = dyn Iterator<Item: Copy, Item: Send>;
 //~^ ERROR the value of the associated type `Item` (from trait `Iterator`) is already specified [E0719]
-//~| ERROR could not find defining uses
-//~| ERROR could not find defining uses
 type TADyn2 = Box<dyn Iterator<Item: Copy, Item: Copy>>;
 //~^ ERROR the value of the associated type `Item` (from trait `Iterator`) is already specified [E0719]
-//~| ERROR could not find defining uses
-//~| ERROR could not find defining uses
 type TADyn3 = dyn Iterator<Item: 'static, Item: 'static>;
 //~^ ERROR the value of the associated type `Item` (from trait `Iterator`) is already specified [E0719]
-//~| ERROR could not find defining uses
-//~| ERROR could not find defining uses
 
 fn main() {}