hide the details of the type for Conflict

src/cargo/core/resolver/conflict_cache.rs

@@ -2,15 +2,15 @@ use std::collections::{BTreeMap, HashMap, HashSet};
 
 use log::trace;
 
-use super::types::ConflictReason;
+use super::types::{Conflict, ConflictReason};
 use crate::core::resolver::Context;
 use crate::core::{Dependency, PackageId};
 
 /// This is a trie for storing a large number of sets designed to
 /// efficiently see if any of the stored sets are a subset of a search set.
 enum ConflictStoreTrie {
     /// One of the stored sets.
-    Leaf(BTreeMap<PackageId, ConflictReason>),
+    Leaf(Conflict),
     /// A map from an element to a subtrie where
     /// all the sets in the subtrie contains that element.
     Node(BTreeMap<PackageId, ConflictStoreTrie>),
@@ -19,11 +19,7 @@ enum ConflictStoreTrie {
 impl ConflictStoreTrie {
     /// Finds any known set of conflicts, if any,
     /// which are activated in `cx` and pass the `filter` specified?
-    fn find_conflicting(
-        &self,
-        cx: &Context,
-        must_contain: Option<PackageId>,
-    ) -> Option<&BTreeMap<PackageId, ConflictReason>> {
+    fn find_conflicting(&self, cx: &Context, must_contain: Option<PackageId>) -> Option<&Conflict> {
         match self {
             ConflictStoreTrie::Leaf(c) => {
                 if must_contain.is_none() {
@@ -57,11 +53,7 @@ impl ConflictStoreTrie {
         }
     }
 
-    fn insert(
-        &mut self,
-        mut iter: impl Iterator<Item = PackageId>,
-        con: BTreeMap<PackageId, ConflictReason>,
-    ) {
+    fn insert(&mut self, mut iter: impl Iterator<Item = PackageId>, con: Conflict) {
         if let Some(pid) = iter.next() {
             if let ConflictStoreTrie::Node(p) = self {
                 p.entry(pid)
@@ -147,7 +139,7 @@ impl ConflictCache {
         cx: &Context,
         dep: &Dependency,
         must_contain: Option<PackageId>,
-    ) -> Option<&BTreeMap<PackageId, ConflictReason>> {
+    ) -> Option<&Conflict> {
         let out = self
             .con_from_dep
             .get(dep)?
@@ -161,18 +153,14 @@ impl ConflictCache {
         }
         out
     }
-    pub fn conflicting(
-        &self,
-        cx: &Context,
-        dep: &Dependency,
-    ) -> Option<&BTreeMap<PackageId, ConflictReason>> {
+    pub fn conflicting(&self, cx: &Context, dep: &Dependency) -> Option<&Conflict> {
         self.find_conflicting(cx, dep, None)
     }
 
     /// Adds to the cache a conflict of the form:
     /// `dep` is known to be unresolvable if
     /// all the `PackageId` entries are activated.
-    pub fn insert(&mut self, dep: &Dependency, con: &BTreeMap<PackageId, ConflictReason>) {
+    pub fn insert(&mut self, dep: &Dependency, con: &Conflict) {
         if con.values().any(|c| *c == ConflictReason::PublicDependency) {
             // TODO: needs more info for back jumping
             // for now refuse to cache it.

src/cargo/core/resolver/context.rs

@@ -1,4 +1,4 @@
-use std::collections::{BTreeMap, HashMap, HashSet};
+use std::collections::{HashMap, HashSet};
 use std::rc::Rc;
 
 // "ensure" seems to require "bail" be in scope (macro hygiene issue?).
@@ -12,7 +12,7 @@ use crate::util::CargoResult;
 use crate::util::Graph;
 
 use super::errors::ActivateResult;
-use super::types::{ConflictReason, DepInfo, GraphNode, Method, RcList, RegistryQueryer};
+use super::types::{Conflict, ConflictReason, DepInfo, GraphNode, Method, RcList, RegistryQueryer};
 
 pub use super::encode::{EncodableDependency, EncodablePackageId, EncodableResolve};
 pub use super::encode::{Metadata, WorkspaceResolve};
@@ -155,7 +155,7 @@ impl Context {
     pub fn is_conflicting(
         &self,
         parent: Option<PackageId>,
-        conflicting_activations: &BTreeMap<PackageId, ConflictReason>,
+        conflicting_activations: &Conflict,
     ) -> bool {
         conflicting_activations
             .keys()

src/cargo/core/resolver/errors.rs

@@ -1,4 +1,3 @@
-use std::collections::BTreeMap;
 use std::fmt;
 
 use crate::core::{Dependency, PackageId, Registry, Summary};
@@ -8,7 +7,7 @@ use failure::{Error, Fail};
 use semver;
 
 use super::context::Context;
-use super::types::{Candidate, ConflictReason};
+use super::types::{Candidate, Conflict, ConflictReason};
 
 /// Error during resolution providing a path of `PackageId`s.
 pub struct ResolveError {
@@ -73,7 +72,7 @@ pub(super) fn activation_error(
     registry: &mut dyn Registry,
     parent: &Summary,
     dep: &Dependency,
-    conflicting_activations: &BTreeMap<PackageId, ConflictReason>,
+    conflicting_activations: &Conflict,
     candidates: &[Candidate],
     config: Option<&Config>,
 ) -> ResolveError {

src/cargo/core/resolver/mod.rs

@@ -62,7 +62,7 @@ use crate::util::errors::CargoResult;
 use crate::util::profile;
 
 use self::context::{Activations, Context};
-use self::types::{Candidate, ConflictReason, DepsFrame, GraphNode};
+use self::types::{Candidate, Conflict, ConflictReason, DepsFrame, GraphNode};
 use self::types::{RcVecIter, RegistryQueryer, RemainingDeps, ResolverProgress};
 
 pub use self::encode::{EncodableDependency, EncodablePackageId, EncodableResolve};
@@ -247,7 +247,7 @@ fn activate_deps_loop(
         //
         // This is a map of package ID to a reason why that packaged caused a
         // conflict for us.
-        let mut conflicting_activations = BTreeMap::new();
+        let mut conflicting_activations = Conflict::new();
 
         // When backtracking we don't fully update `conflicting_activations`
         // especially for the cases that we didn't make a backtrack frame in the
@@ -680,7 +680,7 @@ struct BacktrackFrame {
     parent: Summary,
     dep: Dependency,
     features: Rc<Vec<InternedString>>,
-    conflicting_activations: BTreeMap<PackageId, ConflictReason>,
+    conflicting_activations: Conflict,
 }
 
 /// A helper "iterator" used to extract candidates within a current `Context` of
@@ -727,7 +727,7 @@ impl RemainingCandidates {
     /// original list for the reason listed.
     fn next(
         &mut self,
-        conflicting_prev_active: &mut BTreeMap<PackageId, ConflictReason>,
+        conflicting_prev_active: &mut Conflict,
         cx: &Context,
         dep: &Dependency,
         parent: PackageId,
@@ -845,7 +845,7 @@ fn find_candidate(
     backtrack_stack: &mut Vec<BacktrackFrame>,
     parent: &Summary,
     backtracked: bool,
-    conflicting_activations: &BTreeMap<PackageId, ConflictReason>,
+    conflicting_activations: &Conflict,
 ) -> Option<(Candidate, bool, BacktrackFrame)> {
     while let Some(mut frame) = backtrack_stack.pop() {
         let next = frame.remaining_candidates.next(

src/cargo/core/resolver/types.rs

@@ -1,5 +1,5 @@
 use std::cmp::Ordering;
-use std::collections::{HashMap, HashSet};
+use std::collections::{BTreeMap, HashMap, HashSet};
 use std::ops::Range;
 use std::rc::Rc;
 use std::time::{Duration, Instant};
@@ -425,6 +425,8 @@ impl ConflictReason {
     }
 }
 
+pub type Conflict = BTreeMap<PackageId, ConflictReason>;
+
 pub struct RcVecIter<T> {
     vec: Rc<Vec<T>>,
     rest: Range<usize>,