Allow omitting empty for<> before fn

Author: detrumi

chalk-parse/src/parser.lalrpop

@@ -174,6 +174,10 @@ pub Ty: Ty = {
 
 TyWithoutFor: Ty = {
     <n:Id> => Ty::Id { name: n},
+    "fn" "(" <t:Ty> ")" => Ty::ForAll {
+        lifetime_names: vec![],
+        ty: Box::new(t)
+    },
     "dyn" <b:Plus<QuantifiedInlineBound>> => Ty::Dyn {
         bounds: b,
     },

tests/test/projection.rs

@@ -357,7 +357,7 @@ fn forall_projection() {
         }
 
         goal {
-            for<'a> fn(<Unit as DropLt<'a>>::Item): Eq<for<> fn(Unit)>
+            for<'a> fn(<Unit as DropLt<'a>>::Item): Eq<fn(Unit)>
         } yields {
             "Unique; substitution [], lifetime constraints []"
         }
@@ -384,7 +384,7 @@ fn forall_projection_gat() {
 
         goal {
             forall<T> {
-                for<'a> fn(<Unit as DropOuter<'a>>::Item<T>): Eq<for<> fn(Unit)>
+                for<'a> fn(<Unit as DropOuter<'a>>::Item<T>): Eq<fn(Unit)>
             }
         } yields {
             "No possible solution"
@@ -393,7 +393,7 @@ fn forall_projection_gat() {
         goal {
             forall<T> {
                 if (T: Sized) {
-                    for<'a> fn(<Unit as DropOuter<'a>>::Item<T>): Eq<for<> fn(Unit)>
+                    for<'a> fn(<Unit as DropOuter<'a>>::Item<T>): Eq<fn(Unit)>
                 }
             }
         } yields {
@@ -411,7 +411,7 @@ fn forall_projection_gat() {
         goal {
             forall<T> {
                 if (T: Sized) {
-                    WellFormed(for<'a> fn(<Unit as DropOuter<'a>>::Item<T>): Eq<for<> fn(Unit)>)
+                    WellFormed(for<'a> fn(<Unit as DropOuter<'a>>::Item<T>): Eq<fn(Unit)>)
                 }
             }
         } yields {

tests/test/unify.rs

@@ -130,7 +130,7 @@ fn equality_binder() {
         goal {
             forall<T> {
                 exists<'a> {
-                    for<'c> fn(Ref<'c, T>) = for<> fn(Ref<'a, T>)
+                    for<'c> fn(Ref<'c, T>) = fn(Ref<'a, T>)
                 }
             }
         } yields {
@@ -293,7 +293,7 @@ fn quantified_types() {
         }
 
         goal {
-            forall<'a> { for<> fn(fn1<'a>): Foo }
+            forall<'a> { fn(fn1<'a>): Foo }
         } yields {
             // Lifetime constraints are unsatisfiable
             "Unique; substitution [], \