diff options
Diffstat (limited to 'src/doc/rustc-dev-guide/src/generics.md')
| -rw-r--r-- | src/doc/rustc-dev-guide/src/generics.md | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/src/doc/rustc-dev-guide/src/generics.md b/src/doc/rustc-dev-guide/src/generics.md index 0173bee8f..7512b3b47 100644 --- a/src/doc/rustc-dev-guide/src/generics.md +++ b/src/doc/rustc-dev-guide/src/generics.md @@ -6,7 +6,7 @@ inference, type checking, and trait solving. Conceptually, during these routines that one type is equal to another type and want to swap one out for the other and then swap that out for another type and so on until we eventually get some concrete types (or an error). -In rustc this is done using the `SubstsRef` that we mentioned above (“substs” = “substitutions”). +In rustc this is done using [SubstsRef] (“substs” = “substitutions”). Conceptually, you can think of `SubstsRef` as a list of types that are to be substituted for the generic type parameters of the ADT. @@ -18,6 +18,7 @@ is conceptually like a `&'tcx [GenericArgKind<'tcx>]` slice (but it is actually [list]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/ty/struct.List.html [`GenericArg`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/ty/subst/struct.GenericArg.html [`GenericArgKind`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/ty/subst/enum.GenericArgKind.html +[SubstsRef]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/ty/subst/type.SubstsRef.html So why do we use this `List` type instead of making it really a slice? It has the length "inline", so `&List` is only 32 bits. As a consequence, it cannot be "subsliced" (that only works if the @@ -126,7 +127,7 @@ You may have a couple of followup questions… **`subst`** How do we actually do the substitutions? There is a function for that too! You use [`subst`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/ty/subst/struct.EarlyBinder.html#method.subst) to -replace a `SubstRef` with another list of types. +replace a `SubstsRef` with another list of types. [Here is an example of actually using `subst` in the compiler][substex]. The exact details are not too important, but in this piece of code, we happen to be converting from the `rustc_hir::Ty` to |