fix remaining links
This commit is contained in:
Mark Mansi
Who? Me?!
parent
30b6be0f7d
commit
eec934f762
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@ -26,7 +26,7 @@
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- [Higher-ranked trait bounds](./traits/hrtb.md)
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- [Caching subtleties](./traits/caching.md)
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- [Specialization](./traits/specialization.md)
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- [Trait solving (new-style)](./traits.md)
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- [Trait solving (new-style)](./traits/index.md)
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- [Lowering to logic](./traits/lowering-to-logic.md)
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- [Goals and clauses](./traits/goals-and-clauses.md)
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- [Equality and associated types](./traits/associated-types.md)
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@ -38,12 +38,12 @@
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- [The lowering module in rustc](./traits/lowering-module.md)
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- [Well-formedness checking](./traits/wf.md)
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- [The SLG solver](./traits/slg.md)
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- [An Overview of Chalk](./chalk-overview.md)
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- [An Overview of Chalk](./traits/chalk-overview.md)
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- [Bibliography](./traits/bibliography.md)
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- [Type checking](./type-checking.md)
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- [Method Lookup](./method-lookup.md)
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- [Variance](./variance.md)
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- [The MIR (Mid-level IR)](./mir.md)
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- [The MIR (Mid-level IR)](./mir/index.md)
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- [MIR construction](./mir/construction.md)
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- [MIR visitor and traversal](./mir/visitor.md)
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- [MIR passes: getting the MIR for a function](./mir/passes.md)
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@ -7,18 +7,18 @@ them better.
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Term | Meaning
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------------------------|--------
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AST | the abstract syntax tree produced by the syntax crate; reflects user syntax very closely.
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binder | a "binder" is a place where a variable or type is declared; for example, the `<T>` is a binder for the generic type parameter `T` in `fn foo<T>(..)`, and \|`a`\|` ...` is a binder for the parameter `a`. See [the background chapter for more](./appendix-background.html#free-vs-bound)
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bound variable | a "bound variable" is one that is declared within an expression/term. For example, the variable `a` is bound within the closure expession \|`a`\|` a * 2`. See [the background chapter for more](./appendix-background.html#free-vs-bound)
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binder | a "binder" is a place where a variable or type is declared; for example, the `<T>` is a binder for the generic type parameter `T` in `fn foo<T>(..)`, and \|`a`\|` ...` is a binder for the parameter `a`. See [the background chapter for more](./appendix/background.html#free-vs-bound)
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bound variable | a "bound variable" is one that is declared within an expression/term. For example, the variable `a` is bound within the closure expession \|`a`\|` a * 2`. See [the background chapter for more](./appendix/background.html#free-vs-bound)
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codegen unit | when we produce LLVM IR, we group the Rust code into a number of codegen units. Each of these units is processed by LLVM independently from one another, enabling parallelism. They are also the unit of incremental re-use.
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completeness | completeness is a technical term in type theory. Completeness means that every type-safe program also type-checks. Having both soundness and completeness is very hard, and usually soundness is more important. (see "soundness").
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control-flow graph | a representation of the control-flow of a program; see [the background chapter for more](./appendix-background.html#cfg)
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control-flow graph | a representation of the control-flow of a program; see [the background chapter for more](./appendix/background.html#cfg)
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cx | we tend to use "cx" as an abbrevation for context. See also `tcx`, `infcx`, etc.
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DAG | a directed acyclic graph is used during compilation to keep track of dependencies between queries. ([see more](incremental-compilation.html))
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data-flow analysis | a static analysis that figures out what properties are true at each point in the control-flow of a program; see [the background chapter for more](./appendix-background.html#dataflow)
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data-flow analysis | a static analysis that figures out what properties are true at each point in the control-flow of a program; see [the background chapter for more](./appendix/background.html#dataflow)
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DefId | an index identifying a definition (see `librustc/hir/def_id.rs`). Uniquely identifies a `DefPath`.
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Double pointer | a pointer with additional metadata. See "fat pointer" for more.
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Fat pointer | a two word value carrying the address of some value, along with some further information necessary to put the value to use. Rust includes two kinds of "fat pointers": references to slices, and trait objects. A reference to a slice carries the starting address of the slice and its length. A trait object carries a value's address and a pointer to the trait's implementation appropriate to that value. "Fat pointers" are also known as "wide pointers", and "double pointers".
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free variable | a "free variable" is one that is not bound within an expression or term; see [the background chapter for more](./appendix-background.html#free-vs-bound)
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free variable | a "free variable" is one that is not bound within an expression or term; see [the background chapter for more](./appendix/background.html#free-vs-bound)
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'gcx | the lifetime of the global arena ([see more](ty.html))
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generics | the set of generic type parameters defined on a type or item
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HIR | the High-level IR, created by lowering and desugaring the AST ([see more](hir.html))
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@ -32,36 +32,36 @@ IR | Intermediate Representation. A general term in compil
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local crate | the crate currently being compiled.
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LTO | Link-Time Optimizations. A set of optimizations offered by LLVM that occur just before the final binary is linked. These include optmizations like removing functions that are never used in the final program, for example. _ThinLTO_ is a variant of LTO that aims to be a bit more scalable and efficient, but possibly sacrifices some optimizations. You may also read issues in the Rust repo about "FatLTO", which is the loving nickname given to non-Thin LTO. LLVM documentation: [here][lto] and [here][thinlto]
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[LLVM] | (actually not an acronym :P) an open-source compiler backend. It accepts LLVM IR and outputs native binaries. Various languages (e.g. Rust) can then implement a compiler front-end that output LLVM IR and use LLVM to compile to all the platforms LLVM supports.
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MIR | the Mid-level IR that is created after type-checking for use by borrowck and trans ([see more](./mir.html))
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MIR | the Mid-level IR that is created after type-checking for use by borrowck and trans ([see more](./mir/index.html))
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miri | an interpreter for MIR used for constant evaluation ([see more](./miri.html))
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normalize | a general term for converting to a more canonical form, but in the case of rustc typically refers to [associated type normalization](./traits-associated-types.html#normalize)
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normalize | a general term for converting to a more canonical form, but in the case of rustc typically refers to [associated type normalization](./traits/associated-types.html#normalize)
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newtype | a "newtype" is a wrapper around some other type (e.g., `struct Foo(T)` is a "newtype" for `T`). This is commonly used in Rust to give a stronger type for indices.
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NLL | [non-lexical lifetimes](./mir-regionck.html), an extension to Rust's borrowing system to make it be based on the control-flow graph.
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NLL | [non-lexical lifetimes](./mir/regionck.html), an extension to Rust's borrowing system to make it be based on the control-flow graph.
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node-id or NodeId | an index identifying a particular node in the AST or HIR; gradually being phased out and replaced with `HirId`.
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obligation | something that must be proven by the trait system ([see more](trait-resolution.html))
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projection | a general term for a "relative path", e.g. `x.f` is a "field projection", and `T::Item` is an ["associated type projection"](./traits-goals-and-clauses.html#trait-ref)
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promoted constants | constants extracted from a function and lifted to static scope; see [this section](./mir.html#promoted) for more details.
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obligation | something that must be proven by the trait system ([see more](traits/resolution.html))
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projection | a general term for a "relative path", e.g. `x.f` is a "field projection", and `T::Item` is an ["associated type projection"](./traits/goals-and-clauses.html#trait-ref)
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promoted constants | constants extracted from a function and lifted to static scope; see [this section](./mir/index.html#promoted) for more details.
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provider | the function that executes a query ([see more](query.html))
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quantified | in math or logic, existential and universal quantification are used to ask questions like "is there any type T for which is true?" or "is this true for all types T?"; see [the background chapter for more](./appendix-background.html#quantified)
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quantified | in math or logic, existential and universal quantification are used to ask questions like "is there any type T for which is true?" or "is this true for all types T?"; see [the background chapter for more](./appendix/background.html#quantified)
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query | perhaps some sub-computation during compilation ([see more](query.html))
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region | another term for "lifetime" often used in the literature and in the borrow checker.
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sess | the compiler session, which stores global data used throughout compilation
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side tables | because the AST and HIR are immutable once created, we often carry extra information about them in the form of hashtables, indexed by the id of a particular node.
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sigil | like a keyword but composed entirely of non-alphanumeric tokens. For example, `&` is a sigil for references.
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skolemization | a way of handling subtyping around "for-all" types (e.g., `for<'a> fn(&'a u32)`) as well as solving higher-ranked trait bounds (e.g., `for<'a> T: Trait<'a>`). See [the chapter on skolemization and universes](./mir-regionck.html#skol) for more details.
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skolemization | a way of handling subtyping around "for-all" types (e.g., `for<'a> fn(&'a u32)`) as well as solving higher-ranked trait bounds (e.g., `for<'a> T: Trait<'a>`). See [the chapter on skolemization and universes](./mir/regionck.html#skol) for more details.
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soundness | soundness is a technical term in type theory. Roughly, if a type system is sound, then if a program type-checks, it is type-safe; i.e. I can never (in safe rust) force a value into a variable of the wrong type. (see "completeness").
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span | a location in the user's source code, used for error reporting primarily. These are like a file-name/line-number/column tuple on steroids: they carry a start/end point, and also track macro expansions and compiler desugaring. All while being packed into a few bytes (really, it's an index into a table). See the Span datatype for more.
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substs | the substitutions for a given generic type or item (e.g. the `i32`, `u32` in `HashMap<i32, u32>`)
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tcx | the "typing context", main data structure of the compiler ([see more](ty.html))
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'tcx | the lifetime of the currently active inference context ([see more](ty.html))
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trait reference | the name of a trait along with a suitable set of input type/lifetimes ([see more](./traits-goals-and-clauses.html#trait-ref))
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trait reference | the name of a trait along with a suitable set of input type/lifetimes ([see more](./traits/goals-and-clauses.html#trait-ref))
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token | the smallest unit of parsing. Tokens are produced after lexing ([see more](the-parser.html)).
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[TLS] | Thread-Local Storage. Variables may be defined so that each thread has its own copy (rather than all threads sharing the variable). This has some interactions with LLVM. Not all platforms support TLS.
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trans | the code to translate MIR into LLVM IR.
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trait reference | a trait and values for its type parameters ([see more](ty.html)).
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ty | the internal representation of a type ([see more](ty.html)).
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UFCS | Universal Function Call Syntax. An unambiguous syntax for calling a method ([see more](type-checking.html)).
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variance | variance determines how changes to a generic type/lifetime parameter affect subtyping; for example, if `T` is a subtype of `U`, then `Vec<T>` is a subtype `Vec<U>` because `Vec` is *covariant* in its generic parameter. See [the background chapter](./appendix-background.html#variance) for a more general explanation. See the [variance chapter](./variance.html) for an explanation of how type checking handles variance.
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variance | variance determines how changes to a generic type/lifetime parameter affect subtyping; for example, if `T` is a subtype of `U`, then `Vec<T>` is a subtype `Vec<U>` because `Vec` is *covariant* in its generic parameter. See [the background chapter](./appendix/background.html#variance) for a more general explanation. See the [variance chapter](./variance.html) for an explanation of how type checking handles variance.
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Wide pointer | a pointer with additional metadata. See "fat pointer" for more.
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[LLVM]: https://llvm.org/
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@ -21,7 +21,7 @@ Doing borrow checking on MIR has two key advantages:
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can see
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[a list of bugs that the MIR-based borrow checker fixes here][47366].)
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- Even more importantly, using the MIR enables ["non-lexical lifetimes"][nll],
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which are regions derived from the control-flow graph.
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which are regions derived from the control-flow graph.
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[47366]: https://github.com/rust-lang/rust/issues/47366
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[nll]: http://rust-lang.github.io/rfcs/2094-nll.html
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@ -43,17 +43,17 @@ The overall flow of the borrow checker is as follows:
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include references to the new regions that we are computing.
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- We then invoke `nll::replace_regions_in_mir` to modify this copy C.
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Among other things, this function will replace all of the regions in
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the MIR with fresh [inference variables](./appendix-glossary.html).
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- (More details can be found in [the regionck section](./mir-regionck.html).)
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the MIR with fresh [inference variables](./appendix/glossary.html).
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- (More details can be found in [the regionck section](./mir/regionck.html).)
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- Next, we perform a number of [dataflow
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analyses](./appendix-background.html#dataflow)
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analyses](./appendix/background.html#dataflow)
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that compute what data is moved and when. The results of these analyses
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are needed to do both borrow checking and region inference.
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- Using the move data, we can then compute the values of all the regions in the
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MIR.
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- (More details can be found in [the NLL section](./mir-regionck.html).)
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- (More details can be found in [the NLL section](./mir/regionck.html).)
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- Finally, the borrow checker itself runs, taking as input (a) the
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results of move analysis and (b) the regions computed by the region
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checker. This allows us to figure out which loans are still in scope
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at any particular point.
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@ -26,7 +26,7 @@ Some of the key characteristics of MIR are:
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- It does not have nested expressions.
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- All types in MIR are fully explicit.
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[cfg]: ./appendix-background.html#cfg
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[cfg]: ./appendix/background.html#cfg
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## Key MIR vocabulary
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@ -244,4 +244,4 @@ but [you can read about those below](#promoted)).
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[mir]: https://github.com/rust-lang/rust/tree/master/src/librustc/mir
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[mirmanip]: https://github.com/rust-lang/rust/tree/master/src/librustc_mir
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[mir]: https://github.com/rust-lang/rust/tree/master/src/librustc/mir
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[newtype'd]: appendix-glossary.html
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[newtype'd]: appendix/glossary.html
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@ -174,4 +174,4 @@ alternatives in [rust-lang/rust#41710].
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[rust-lang/rust#41710]: https://github.com/rust-lang/rust/issues/41710
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[mirtransform]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/transform/
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[`NoLandingPads`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/transform/no_landing_pads/struct.NoLandingPads.html
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[MIR visitor]: mir-visitor.html
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[MIR visitor]: mir/visitor.html
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@ -35,7 +35,7 @@ The MIR-based region analysis consists of two major functions:
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- More details to come, though the [NLL RFC] also includes fairly thorough
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(and hopefully readable) coverage.
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[fvb]: appendix-background.html#free-vs-bound
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[fvb]: appendix/background.html#free-vs-bound
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[NLL RFC]: http://rust-lang.github.io/rfcs/2094-nll.html
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## Universal regions
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@ -131,7 +131,7 @@ the type of `foo` the type `bar` expects
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We handle this sort of subtyping by taking the variables that are
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bound in the supertype and **skolemizing** them: this means that we
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replace them with
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[universally quantified](appendix-background.html#quantified)
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[universally quantified](appendix/background.html#quantified)
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representatives, written like `!1`. We call these regions "skolemized
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regions" -- they represent, basically, "some unknown region".
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@ -148,7 +148,7 @@ what we wanted.
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So let's work through what happens next. To check if two functions are
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subtypes, we check if their arguments have the desired relationship
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(fn arguments are [contravariant](./appendix-background.html#variance), so
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(fn arguments are [contravariant](./appendix/background.html#variance), so
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we swap the left and right here):
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```text
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@ -187,7 +187,7 @@ Here, the root universe would consist of the lifetimes `'static` and
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the same concept to types, in which case the types `Foo` and `T` would
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be in the root universe (along with other global types, like `i32`).
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Basically, the root universe contains all the names that
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[appear free](./appendix-background.html#free-vs-bound) in the body of `bar`.
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[appear free](./appendix/background.html#free-vs-bound) in the body of `bar`.
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Now let's extend `bar` a bit by adding a variable `x`:
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@ -41,7 +41,7 @@ trait query: `?A: Foo<'static, ?B>`, where `?A` and `?B` are unbound.
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This query contains two unbound variables, but it also contains the
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lifetime `'static`. The trait system generally ignores all lifetimes
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and treats them equally, so when canonicalizing, we will *also*
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replace any [free lifetime](./appendix-background.html#free-vs-bound) with a
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replace any [free lifetime](./appendix/background.html#free-vs-bound) with a
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canonical variable. Therefore, we get the following result:
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```text
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@ -131,18 +131,18 @@ See [The SLG Solver][slg].
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[rustc-issues]: https://github.com/rust-lang-nursery/rustc-guide/issues
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[chalk]: https://github.com/rust-lang-nursery/chalk
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[lowering-to-logic]: traits-lowering-to-logic.html
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[lowering-rules]: traits-lowering-rules.html
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[lowering-to-logic]: traits/lowering-to-logic.html
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[lowering-rules]: traits/lowering-rules.html
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[ast]: https://en.wikipedia.org/wiki/Abstract_syntax_tree
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[chalk-ast]: https://github.com/rust-lang-nursery/chalk/blob/master/chalk-parse/src/ast.rs
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[universal quantification]: https://en.wikipedia.org/wiki/Universal_quantification
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[lowering-forall]: https://rust-lang-nursery.github.io/rustc-guide/traits-lowering-to-logic.html#type-checking-generic-functions-beyond-horn-clauses
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[lowering-forall]: ./traits/lowering-to-logic.html#type-checking-generic-functions-beyond-horn-clauses
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[programclause]: https://github.com/rust-lang-nursery/chalk/blob/94a1941a021842a5fcb35cd043145c8faae59f08/src/ir.rs#L721
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[clause]: https://github.com/rust-lang-nursery/chalk/blob/master/GLOSSARY.md#clause
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[goals-and-clauses]: traits-goals-and-clauses.html
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[goals-and-clauses]: ./traits/goals-and-clauses.html
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[well-formedness-checks]: https://github.com/rust-lang-nursery/chalk/blob/94a1941a021842a5fcb35cd043145c8faae59f08/src/ir/lowering.rs#L230-L232
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[ir-code]: https://github.com/rust-lang-nursery/chalk/blob/master/src/ir.rs
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[HIR]: hir.html
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[binders-struct]: https://github.com/rust-lang-nursery/chalk/blob/94a1941a021842a5fcb35cd043145c8faae59f08/src/ir.rs#L661
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[rules-environment]: https://github.com/rust-lang-nursery/chalk/blob/94a1941a021842a5fcb35cd043145c8faae59f08/src/rules.rs#L9
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[slg]: traits-slg.html
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[slg]: ./traits/slg.html
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@ -4,7 +4,7 @@
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[process of being implemented][wg]; this chapter serves as a kind of
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in-progress design document. If you would prefer to read about how the
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current trait solver works, check out
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[this other chapter](./trait-resolution.html). (By the way, if you
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[this other chapter](./traits/resolution.html). (By the way, if you
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would like to help in hacking on the new solver, you will find
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instructions for getting involved in the
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[Traits Working Group tracking issue][wg].) 🚧
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@ -6,7 +6,7 @@ draws heavily on the [type inference] and [trait solving].)
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[typeck]: https://github.com/rust-lang/rust/tree/master/src/librustc_typeck
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[type inference]: type-inference.html
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[trait solving]: trait-resolution.html
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[trait solving]: traits/resolution.html
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## Type collection
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@ -2,7 +2,7 @@
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For a more general background on variance, see the [background] appendix.
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[background]: ./appendix-background.html
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[background]: ./appendix/background.html
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During type checking we must infer the variance of type and lifetime
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parameters. The algorithm is taken from Section 4 of the paper ["Taming the
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