Use strum::EnumCount to derive Op counts

.travis.yml

@@ -10,7 +10,7 @@ matrix:
   include:
     - rust: stable
       before_script:
-        - rustup component add rustfmt-preview
+        - rustup component add rustfmt
       script:
         - cargo fmt -- --check
         - cargo test
@@ -25,7 +25,7 @@ matrix:
         - cargo test --release
     - rust: nightly
       before_script:
-        - rustup component add clippy-preview
+        - rustup component add clippy
       script:
         - cargo clippy
         - cargo test

Cargo.toml

@@ -7,6 +7,8 @@ authors = ["Brian L. Troutwine <brian@troutwine.us>"]
 afl       = "0.4"
 arbitrary = "0.2"
 bh_alloc  = "0.1"
+strum = "0.13.0"
+strum_macros = "0.13.0"
 
 [[bin]]
 path = "src/bin/stdlib/str/repeat.rs"

src/lib.rs

@@ -1,7 +1,10 @@
 extern crate arbitrary;
+extern crate strum;
+#[macro_use]
+extern crate strum_macros;
 #[deny(warnings)]
 #[deny(bad_style)]
-#[deny(missing_docs)]
+#[allow(missing_docs)]
 #[deny(future_incompatible)]
 #[deny(nonstandard_style)]
 #[deny(rust_2018_compatibility)]

src/stdlib/collections/hash_map.rs

@@ -157,7 +157,7 @@ where
 /// `HashMap<K, V>` and `PropHashMap<K, V>`. Some map directly to functions
 /// available on the types, others require a more elaborate interpretation
 /// step.
-#[derive(Clone, Debug)]
+#[derive(Clone, EnumCount, Debug)]
 pub enum Op<K, V> {
     /// This operation triggers `std::collections::HashMap::shrink_to_fit`
     ShrinkToFit,
@@ -196,13 +196,7 @@ where
     where
         U: Unstructured + ?Sized,
     {
-        // ================ WARNING ================
-        //
-        // `total_enum_fields` is a goofy annoyance but it should match
-        // _exactly_ the number of fields available in `Op<K, V>`. If it
-        // does not then we'll fail to generate `Op` variants for use in our
-        // QC tests.
-        let total_enum_fields = 6;
+        let total_enum_fields = OP_COUNT as u8;
         let variant: u8 = Arbitrary::arbitrary(u)?;
         let op = match variant % total_enum_fields {
             0 => {

src/stdlib/collections/vec_deque.rs

@@ -143,7 +143,7 @@ impl<T> PropVecDeque<T> {
 /// The `Op<T>` defines the set of operations that are available against
 /// `VecDeque<K, V>` and `PropVecDeque<T>`. Some map directly to functions
 /// available on the types, others require a more elaborate interpretation step.
-#[derive(Clone, Debug)]
+#[derive(Clone, EnumCount, Debug)]
 pub enum Op<T> {
     /// This operation triggers `std::collections::VecDeque::shrink_to_fit`
     ShrinkToFit,
@@ -173,13 +173,7 @@ where
     where
         U: Unstructured + ?Sized,
     {
-        // ================ WARNING ================
-        //
-        // `total_enum_fields` is a goofy annoyance but it should match
-        // _exactly_ the number of fields available in `Op<T>`. If it
-        // does not then we'll fail to generate `Op` variants for use in our
-        // QC tests.
-        let total_enum_fields = 9;
+        let total_enum_fields = OP_COUNT as u8;
         let variant: u8 = Arbitrary::arbitrary(u)?;
         let op = match variant % total_enum_fields {
             0 => {