nyaa

Author: lcnr

src/trait-bounds.md

@@ -64,7 +64,7 @@ r[bound.satisfaction.impl]
 
 [bound.satisfaction.impl.builtin]
 
-There exists impls which are automatically generated by the compiler.
+There exist impls which are automatically generated by the compiler.
 
 - `Sized`,`Copy`, `Clone`,...
 

src/types.md

@@ -152,14 +152,27 @@ let a: List<i32> = List::Cons(7, Box::new(List::Cons(13, Box::new(List::Nil))));
 
 ## Equality of types
 
+r[types.equality]
+
 Equality and subtyping of types is generally structural. If the outermost type constructors are the same,
-the fields are pairwise related. The only exceptions from this rule are higher ranked types and alias types
+corresponding generic arguments are compared. The only exceptions from this rule are higher ranked types and alias types.
+
+r[types.equality.aliases]
+
+Aliases are compared by first normalizing them to a *rigid* type? and then equating their type constructors and recursing into their generic arguments.
+
+r[types.equality.higher-ranked]
+
+Function pointers and trait objects may be higher-ranked.
+
+r[types.equality.higher-ranked.sub]
+
+Subtyping is checked by instantiating the `for` of the subtype with inference variables and the `for` of the supertype with placeholders before relating them as normal.
+
+r[types.equality.higher-ranked.eq]
 
-higher ranked types:
-uwu, instantiate binder with placeholders, eq
+Equality is checked by both instantiating the `for` of the lhs with inference variables and the `for` of the rhs with placeholders before equating them, and also doing the opposite.
 
-aliases
-normalized to a rigid type, then equated as normal
 
 [Array]: types/array.md
 [Boolean]: types/boolean.md

src/types/alias-types.md

@@ -6,7 +6,8 @@ r[type.alias]
 
 r[type.alias.rigid]
 
-Aliases might be treated as rigid in their current environment. In this case they behave like other rigid types.
+Aliases might be treated as *rigid* in their current environment. In this case they behave like other types.
+Their equality is structural, *rigid* aliases are only equal if both have the same type constructor and equal corresponding arguments.
 
 r[type.alias.normalization]