Provide more context when denying invalid type params

compiler/rustc_typeck/src/check/fn_ctxt/_impl.rs

@@ -1228,6 +1228,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     None
                 }
             }),
+            |_| {},
         );
 
         if let Res::Local(hid) = res {

compiler/rustc_typeck/src/check/fn_ctxt/checks.rs

@@ -1564,13 +1564,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             QPath::TypeRelative(ref qself, ref segment) => {
                 let ty = self.to_ty(qself);
 
-                let res = if let hir::TyKind::Path(QPath::Resolved(_, ref path)) = qself.kind {
-                    path.res
-                } else {
-                    Res::Err
-                };
                 let result = <dyn AstConv<'_>>::associated_path_to_ty(
-                    self, hir_id, path_span, ty, res, segment, true,
+                    self, hir_id, path_span, ty, qself, segment, true,
                 );
                 let ty = result.map(|(ty, _, _)| ty).unwrap_or_else(|_| self.tcx().ty_error());
                 let result = result.map(|(_, kind, def_id)| (kind, def_id));

src/test/ui/derives/issue-97343.rs

@@ -1,7 +1,7 @@
 use std::fmt::Debug;
 
 #[derive(Debug)]
-pub struct Irrelevant<Irrelevant> { //~ ERROR type arguments are not allowed for this type
+pub struct Irrelevant<Irrelevant> { //~ ERROR type arguments are not allowed on type parameter
     irrelevant: Irrelevant,
 }
 

src/test/ui/derives/issue-97343.stderr

@@ -1,11 +1,19 @@
-error[E0109]: type arguments are not allowed for this type
+error[E0109]: type arguments are not allowed on type parameter `Irrelevant`
   --> $DIR/issue-97343.rs:4:23
    |
 LL | #[derive(Debug)]
-   |          ----- in this derive macro expansion
+   |          -----
+   |          |
+   |          not allowed on this
+   |          in this derive macro expansion
 LL | pub struct Irrelevant<Irrelevant> {
    |                       ^^^^^^^^^^ type argument not allowed
    |
+note: type parameter `Irrelevant` defined here
+  --> $DIR/issue-97343.rs:4:23
+   |
+LL | pub struct Irrelevant<Irrelevant> {
+   |                       ^^^^^^^^^^
    = note: this error originates in the derive macro `Debug` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: aborting due to previous error

src/test/ui/error-codes/E0109.stderr

@@ -1,8 +1,16 @@
-error[E0109]: type arguments are not allowed for this type
+error[E0109]: type arguments are not allowed on this type
   --> $DIR/E0109.rs:1:14
    |
 LL | type X = u32<i32>;
-   |              ^^^ type argument not allowed
+   |          --- ^^^ type argument not allowed
+   |          |
+   |          not allowed on this
+   |
+help: primitive type `u32` doesn't have type parameters
+   |
+LL - type X = u32<i32>;
+LL + type X = u32;
+   | 
 
 error: aborting due to previous error
 

src/test/ui/error-codes/E0110.stderr

@@ -1,8 +1,16 @@
-error[E0109]: lifetime arguments are not allowed for this type
+error[E0109]: lifetime arguments are not allowed on this type
   --> $DIR/E0110.rs:1:14
    |
 LL | type X = u32<'static>;
-   |              ^^^^^^^ lifetime argument not allowed
+   |          --- ^^^^^^^ lifetime argument not allowed
+   |          |
+   |          not allowed on this
+   |
+help: primitive type `u32` doesn't have type parameters
+   |
+LL - type X = u32<'static>;
+LL + type X = u32;
+   | 
 
 error: aborting due to previous error
 

src/test/ui/issues/issue-22706.rs

@@ -1,3 +1,3 @@
 fn is_copy<T: ::std::marker<i32>::Copy>() {}
-//~^ ERROR type arguments are not allowed for this type [E0109]
+//~^ ERROR type arguments are not allowed on module `marker` [E0109]
 fn main() {}

src/test/ui/issues/issue-22706.stderr

@@ -1,8 +1,10 @@
-error[E0109]: type arguments are not allowed for this type
+error[E0109]: type arguments are not allowed on module `marker`
   --> $DIR/issue-22706.rs:1:29
    |
 LL | fn is_copy<T: ::std::marker<i32>::Copy>() {}
-   |                             ^^^ type argument not allowed
+   |                      ------ ^^^ type argument not allowed
+   |                      |
+   |                      not allowed on this
 
 error: aborting due to previous error
 

src/test/ui/issues/issue-57924.rs

@@ -3,7 +3,7 @@ pub struct Gcm<E>(E);
 impl<E> Gcm<E> {
     pub fn crash(e: E) -> Self {
         Self::<E>(e)
-        //~^ ERROR type arguments are not allowed for this type
+        //~^ ERROR type arguments are not allowed on self constructor
     }
 }
 

src/test/ui/issues/issue-57924.stderr

@@ -1,8 +1,10 @@
-error[E0109]: type arguments are not allowed for this type
+error[E0109]: type arguments are not allowed on self constructor
   --> $DIR/issue-57924.rs:5:16
    |
 LL |         Self::<E>(e)
-   |                ^ type argument not allowed
+   |         ----   ^ type argument not allowed
+   |         |
+   |         not allowed on this
 
 error: aborting due to previous error
 

src/test/ui/issues/issue-60989.rs

@@ -10,9 +10,9 @@ impl From<A> for B {
 fn main() {
     let c1 = ();
     c1::<()>;
-    //~^ ERROR type arguments are not allowed for this type
+    //~^ ERROR type arguments are not allowed on local variable
 
     let c1 = A {};
     c1::<dyn Into<B>>;
-    //~^ ERROR type arguments are not allowed for this type
+    //~^ ERROR type arguments are not allowed on local variable
 }

src/test/ui/issues/issue-60989.stderr

@@ -1,14 +1,18 @@
-error[E0109]: type arguments are not allowed for this type
+error[E0109]: type arguments are not allowed on local variable
   --> $DIR/issue-60989.rs:12:10
    |
 LL |     c1::<()>;
-   |          ^^ type argument not allowed
+   |     --   ^^ type argument not allowed
+   |     |
+   |     not allowed on this
 
-error[E0109]: type arguments are not allowed for this type
+error[E0109]: type arguments are not allowed on local variable
   --> $DIR/issue-60989.rs:16:10
    |
 LL |     c1::<dyn Into<B>>;
-   |          ^^^^^^^^^^^ type argument not allowed
+   |     --   ^^^^^^^^^^^ type argument not allowed
+   |     |
+   |     not allowed on this
 
 error: aborting due to 2 previous errors
 

src/test/ui/mod-subitem-as-enum-variant.rs

@@ -5,5 +5,5 @@ mod Mod {
 fn main() {
     Mod::FakeVariant::<i32>(0);
     Mod::<i32>::FakeVariant(0);
-    //~^ ERROR type arguments are not allowed for this type [E0109]
+    //~^ ERROR type arguments are not allowed on module `Mod` [E0109]
 }

src/test/ui/mod-subitem-as-enum-variant.stderr

@@ -1,8 +1,10 @@
-error[E0109]: type arguments are not allowed for this type
+error[E0109]: type arguments are not allowed on module `Mod`
   --> $DIR/mod-subitem-as-enum-variant.rs:7:11
    |
 LL |     Mod::<i32>::FakeVariant(0);
-   |           ^^^ type argument not allowed
+   |     ---   ^^^ type argument not allowed
+   |     |
+   |     not allowed on this
 
 error: aborting due to previous error
 

src/test/ui/structs/struct-path-associated-type.rs

@@ -13,7 +13,7 @@ fn f<T: Tr>() {
     //~^ ERROR expected struct, variant or union type, found associated type
     let z = T::A::<u8> {};
     //~^ ERROR expected struct, variant or union type, found associated type
-    //~| ERROR type arguments are not allowed for this type
+    //~| ERROR type arguments are not allowed on this type
     match S {
         T::A {} => {}
         //~^ ERROR expected struct, variant or union type, found associated type
@@ -22,7 +22,7 @@ fn f<T: Tr>() {
 
 fn g<T: Tr<A = S>>() {
     let s = T::A {}; // OK
-    let z = T::A::<u8> {}; //~ ERROR type arguments are not allowed for this type
+    let z = T::A::<u8> {}; //~ ERROR type arguments are not allowed on this type
     match S {
         T::A {} => {} // OK
     }

src/test/ui/structs/struct-path-associated-type.stderr

@@ -4,11 +4,13 @@ error[E0071]: expected struct, variant or union type, found associated type
 LL |     let s = T::A {};
    |             ^^^^ not a struct
 
-error[E0109]: type arguments are not allowed for this type
+error[E0109]: type arguments are not allowed on this type
   --> $DIR/struct-path-associated-type.rs:14:20
    |
 LL |     let z = T::A::<u8> {};
-   |                    ^^ type argument not allowed
+   |                -   ^^ type argument not allowed
+   |                |
+   |                not allowed on this
 
 error[E0071]: expected struct, variant or union type, found associated type
   --> $DIR/struct-path-associated-type.rs:14:13
@@ -22,11 +24,13 @@ error[E0071]: expected struct, variant or union type, found associated type
 LL |         T::A {} => {}
    |         ^^^^ not a struct
 
-error[E0109]: type arguments are not allowed for this type
+error[E0109]: type arguments are not allowed on this type
   --> $DIR/struct-path-associated-type.rs:25:20
    |
 LL |     let z = T::A::<u8> {};
-   |                    ^^ type argument not allowed
+   |                -   ^^ type argument not allowed
+   |                |
+   |                not allowed on this
 
 error[E0223]: ambiguous associated type
   --> $DIR/struct-path-associated-type.rs:32:13

src/test/ui/structs/struct-path-self.rs

@@ -6,7 +6,7 @@ trait Tr {
         //~^ ERROR expected struct, variant or union type, found type parameter
         let z = Self::<u8> {};
         //~^ ERROR expected struct, variant or union type, found type parameter
-        //~| ERROR type arguments are not allowed for this type
+        //~| ERROR type arguments are not allowed on self type
         match s {
             Self { .. } => {}
             //~^ ERROR expected struct, variant or union type, found type parameter
@@ -17,7 +17,7 @@ trait Tr {
 impl Tr for S {
     fn f() {
         let s = Self {}; // OK
-        let z = Self::<u8> {}; //~ ERROR type arguments are not allowed for this type
+        let z = Self::<u8> {}; //~ ERROR type arguments are not allowed on self type
         match s {
             Self { .. } => {} // OK
         }
@@ -27,7 +27,7 @@ impl Tr for S {
 impl S {
     fn g() {
         let s = Self {}; // OK
-        let z = Self::<u8> {}; //~ ERROR type arguments are not allowed for this type
+        let z = Self::<u8> {}; //~ ERROR type arguments are not allowed on self type
         match s {
             Self { .. } => {} // OK
         }

src/test/ui/structs/struct-path-self.stderr

@@ -4,11 +4,19 @@ error[E0071]: expected struct, variant or union type, found type parameter `Self
 LL |         let s = Self {};
    |                 ^^^^ not a struct
 
-error[E0109]: type arguments are not allowed for this type
+error[E0109]: type arguments are not allowed on self type
   --> $DIR/struct-path-self.rs:7:24
    |
 LL |         let z = Self::<u8> {};
-   |                        ^^ type argument not allowed
+   |                 ----   ^^ type argument not allowed
+   |                 |
+   |                 not allowed on this
+   |
+help: the `Self` type doesn't accept type parameters
+   |
+LL -         let z = Self::<u8> {};
+LL +         let z = Self {};
+   | 
 
 error[E0071]: expected struct, variant or union type, found type parameter `Self`
   --> $DIR/struct-path-self.rs:7:17
@@ -22,17 +30,49 @@ error[E0071]: expected struct, variant or union type, found type parameter `Self
 LL |             Self { .. } => {}
    |             ^^^^ not a struct
 
-error[E0109]: type arguments are not allowed for this type
+error[E0109]: type arguments are not allowed on self type
   --> $DIR/struct-path-self.rs:20:24
    |
 LL |         let z = Self::<u8> {};
-   |                        ^^ type argument not allowed
+   |                 ----   ^^ type argument not allowed
+   |                 |
+   |                 not allowed on this
+   |
+note: `Self` is of type `S`
+  --> $DIR/struct-path-self.rs:1:8
+   |
+LL | struct S;
+   |        ^ `Self` corresponds to this type, which doesn't have type parameters
+...
+LL | impl Tr for S {
+   | ------------- `Self` is on type `S` in this `impl`
+help: the `Self` type doesn't accept type parameters
+   |
+LL -         let z = Self::<u8> {};
+LL +         let z = Self {};
+   | 
 
-error[E0109]: type arguments are not allowed for this type
+error[E0109]: type arguments are not allowed on self type
   --> $DIR/struct-path-self.rs:30:24
    |
 LL |         let z = Self::<u8> {};
-   |                        ^^ type argument not allowed
+   |                 ----   ^^ type argument not allowed
+   |                 |
+   |                 not allowed on this
+   |
+note: `Self` is of type `S`
+  --> $DIR/struct-path-self.rs:1:8
+   |
+LL | struct S;
+   |        ^ `Self` corresponds to this type, which doesn't have type parameters
+...
+LL | impl S {
+   | ------ `Self` is on type `S` in this `impl`
+help: the `Self` type doesn't accept type parameters
+   |
+LL -         let z = Self::<u8> {};
+LL +         let z = Self {};
+   | 
 
 error: aborting due to 6 previous errors