Auto merge of #64790 - Centril:rip-ast-borrowck, r=matthewjasper

Rest In Peace, AST borrowck (2012-2019)

After having served us for 7 years, the AST borrow-checker is no more.

This PR starts from the commit `rm -rf librustc_ast_borrowck`, building on #64221, and is probably best read commit by commit.

Migrate mode is not removed yet as it may be useful for NLL => polonius and it is also used for the `mutable_borrow_reservation_conflict` issue (#59159).

r? @matthewjasper

------------------------

![ast-borrowck-rip](https://user-images.githubusercontent.com/855702/65646791-91a87600-dffc-11e9-9814-deed6b821c80.png)

Author: bors

Cargo.lock

@@ -3337,17 +3337,6 @@ dependencies = [
  "core",
 ]
 
-[[package]]
-name = "rustc_ast_borrowck"
-version = "0.0.0"
-dependencies = [
- "graphviz",
- "log",
- "rustc",
- "rustc_data_structures",
- "syntax_pos",
-]
-
 [[package]]
 name = "rustc_codegen_llvm"
 version = "0.0.0"
@@ -3425,7 +3414,6 @@ dependencies = [
  "lazy_static 1.3.0",
  "log",
  "rustc",
- "rustc_ast_borrowck",
  "rustc_codegen_utils",
  "rustc_data_structures",
  "rustc_errors",
@@ -3483,7 +3471,6 @@ dependencies = [
  "once_cell",
  "rustc",
  "rustc-rayon",
- "rustc_ast_borrowck",
  "rustc_codegen_ssa",
  "rustc_codegen_utils",
  "rustc_data_structures",

src/librustc/arena.rs

@@ -86,7 +86,6 @@ macro_rules! arena_types {
                     rustc::infer::canonical::QueryResponse<'tcx, rustc::ty::Ty<'tcx>>
                 >,
             [few] crate_inherent_impls: rustc::ty::CrateInherentImpls,
-            [decode] borrowck: rustc::middle::borrowck::BorrowCheckResult,
             [few] upstream_monomorphizations:
                 rustc::util::nodemap::DefIdMap<
                     rustc_data_structures::fx::FxHashMap<

src/librustc/hir/mod.rs

@@ -1291,17 +1291,6 @@ pub struct Arm {
     pub body: P<Expr>,
 }
 
-impl Arm {
-    // HACK(or_patterns; Centril | dlrobertson): Remove this and
-    // correctly handle each case in which this method is used.
-    pub fn top_pats_hack(&self) -> &[P<Pat>] {
-        match &self.pat.kind {
-            PatKind::Or(pats) => pats,
-            _ => std::slice::from_ref(&self.pat),
-        }
-    }
-}
-
 #[derive(RustcEncodable, RustcDecodable, Debug, HashStable)]
 pub enum Guard {
     If(P<Expr>),

src/librustc/infer/mod.rs

@@ -93,6 +93,8 @@ impl SuppressRegionErrors {
     /// checks, so we should ignore errors if NLL is (unconditionally)
     /// enabled.
     pub fn when_nll_is_enabled(tcx: TyCtxt<'_>) -> Self {
+        // FIXME(Centril): Once we actually remove `::Migrate` also make
+        // this always `true` and then proceed to eliminate the dead code.
         match tcx.borrowck_mode() {
             // If we're on Migrate mode, report AST region errors
             BorrowckMode::Migrate => SuppressRegionErrors { suppressed: false },

src/librustc/lib.rs

@@ -100,7 +100,6 @@ pub mod infer;
 pub mod lint;
 
 pub mod middle {
-    pub mod borrowck;
     pub mod expr_use_visitor;
     pub mod cstore;
     pub mod dead;

src/librustc/middle/borrowck.rs

@@ -397,10 +397,6 @@ rustc_queries! {
     }
 
     BorrowChecking {
-        query borrowck(key: DefId) -> &'tcx BorrowCheckResult {
-            cache_on_disk_if { key.is_local() }
-        }
-
         /// Borrow-checks the function body. If this is a closure, returns
         /// additional requirements that the closure's creator must verify.
         query mir_borrowck(key: DefId) -> mir::BorrowCheckResult<'tcx> {
@@ -469,7 +465,7 @@ rustc_queries! {
     }
 
     TypeChecking {
-        query check_match(key: DefId) -> SignalledError {
+        query check_match(key: DefId) {
             cache_on_disk_if { key.is_local() }
         }
 

src/librustc/query/mod.rs

@@ -478,14 +478,6 @@ impl BorrowckMode {
             BorrowckMode::Migrate => true,
         }
     }
-
-    /// Returns whether we should emit the AST-based borrow checker errors.
-    pub fn use_ast(self) -> bool {
-        match self {
-            BorrowckMode::Mir => false,
-            BorrowckMode::Migrate => false,
-        }
-    }
 }
 
 pub enum Input {
@@ -1268,14 +1260,6 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
     save_analysis: bool = (false, parse_bool, [UNTRACKED],
         "write syntax and type analysis (in JSON format) information, in \
          addition to normal output"),
-    flowgraph_print_loans: bool = (false, parse_bool, [UNTRACKED],
-        "include loan analysis data in -Z unpretty flowgraph output"),
-    flowgraph_print_moves: bool = (false, parse_bool, [UNTRACKED],
-        "include move analysis data in -Z unpretty flowgraph output"),
-    flowgraph_print_assigns: bool = (false, parse_bool, [UNTRACKED],
-        "include assignment analysis data in -Z unpretty flowgraph output"),
-    flowgraph_print_all: bool = (false, parse_bool, [UNTRACKED],
-        "include all dataflow analysis data in -Z unpretty flowgraph output"),
     print_region_graph: bool = (false, parse_bool, [UNTRACKED],
         "prints region inference graph. \
          Use with RUST_REGION_GRAPH=help for more info"),
@@ -1424,8 +1408,6 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
         valid types are any of the types for `--pretty`, as well as:
         `expanded`, `expanded,identified`,
         `expanded,hygiene` (with internal representations),
-        `flowgraph=<nodeid>` (graphviz formatted flowgraph for node),
-        `flowgraph,unlabelled=<nodeid>` (unlabelled graphviz formatted flowgraph for node),
         `everybody_loops` (all function bodies replaced with `loop {}`),
         `hir` (the HIR), `hir,identified`,
         `hir,typed` (HIR with types for each node),

src/librustc/session/config.rs

@@ -589,14 +589,6 @@ fn test_debugging_options_tracking_hash() {
     assert_eq!(reference.dep_tracking_hash(), opts.dep_tracking_hash());
     opts.debugging_opts.save_analysis = true;
     assert_eq!(reference.dep_tracking_hash(), opts.dep_tracking_hash());
-    opts.debugging_opts.flowgraph_print_loans = true;
-    assert_eq!(reference.dep_tracking_hash(), opts.dep_tracking_hash());
-    opts.debugging_opts.flowgraph_print_moves = true;
-    assert_eq!(reference.dep_tracking_hash(), opts.dep_tracking_hash());
-    opts.debugging_opts.flowgraph_print_assigns = true;
-    assert_eq!(reference.dep_tracking_hash(), opts.dep_tracking_hash());
-    opts.debugging_opts.flowgraph_print_all = true;
-    assert_eq!(reference.dep_tracking_hash(), opts.dep_tracking_hash());
     opts.debugging_opts.print_region_graph = true;
     assert_eq!(reference.dep_tracking_hash(), opts.dep_tracking_hash());
     opts.debugging_opts.parse_only = true;

src/librustc/session/config/tests.rs

@@ -1435,12 +1435,6 @@ impl<'tcx> TyCtxt<'tcx> {
         self.queries.on_disk_cache.serialize(self.global_tcx(), encoder)
     }
 
-    /// If `true`, we should use the AST-based borrowck (we may *also* use
-    /// the MIR-based borrowck).
-    pub fn use_ast_borrowck(self) -> bool {
-        self.borrowck_mode().use_ast()
-    }
-
     /// If `true`, we should use the MIR-based borrowck, but also
     /// fall back on the AST borrowck if the MIR-based one errors.
     pub fn migrate_borrowck(self) -> bool {

src/librustc/ty/context.rs

@@ -4,7 +4,6 @@ use crate::hir::def::{DefKind, Export};
 use crate::hir::{self, TraitCandidate, ItemLocalId, CodegenFnAttrs};
 use crate::infer::canonical::{self, Canonical};
 use crate::lint;
-use crate::middle::borrowck::{BorrowCheckResult, SignalledError};
 use crate::middle::cstore::{ExternCrate, LinkagePreference, NativeLibrary, ForeignModule};
 use crate::middle::cstore::{NativeLibraryKind, DepKind, CrateSource};
 use crate::middle::privacy::AccessLevels;