Use explicit features rather than implicit.

In Rust 2024 edition, implicit features from optional dependencies
are going away and explicit features are required.

This changes all features using optional dependencies to use the
"dep:" syntax to avoid creating implicit features.

It also adds new explicit features for optional dependencies that
didn't previously have an explicit feature to enable them.

This does mean that some previously publicly visible features are
now gone, like `serde`. These features would not have worked
previously as the code is guarded by, for example, checks for
`feature = "serde1"`, so just enabling the optional dependency
wouldn't have been sufficient to enable the code.

Cargo.toml

@@ -30,7 +30,7 @@ features = ["small_rng", "serde1"]
 # Meta-features:
 default = ["std", "std_rng", "getrandom", "small_rng"]
 nightly = [] # some additions requiring nightly Rust
-serde1 = ["serde", "rand_core/serde1"]
+serde1 = ["dep:serde", "rand_core/serde1"]
 
 # Option (enabled by default): without "std" rand uses libcore; this option
 # enables functionality expected to be available on a standard platform.
@@ -46,7 +46,7 @@ getrandom = ["rand_core/getrandom"]
 simd_support = ["zerocopy/simd-nightly"]
 
 # Option (enabled by default): enable StdRng
-std_rng = ["rand_chacha"]
+std_rng = ["dep:rand_chacha"]
 
 # Option: enable SmallRng
 small_rng = []
@@ -56,6 +56,9 @@ small_rng = []
 # Note: enabling this option is expected to affect reproducibility of results.
 unbiased = []
 
+# Option: enable logging
+log = ["dep:log"]
+
 [workspace]
 members = [
     "rand_core",

rand_chacha/Cargo.toml

@@ -33,4 +33,4 @@ rand_core = { path = "../rand_core", version = "=0.9.0-alpha.1", features = ["ge
 default = ["std"]
 getrandom = ["rand_core/getrandom"]
 std = ["ppv-lite86/std", "rand_core/std"]
-serde1 = ["serde"]
+serde1 = ["dep:serde"]

rand_core/Cargo.toml

@@ -27,7 +27,8 @@ all-features = true
 [features]
 std = ["alloc", "getrandom?/std"]
 alloc = []  # enables Vec and Box support without std
-serde1 = ["serde"] # enables serde for BlockRng wrapper
+getrandom = ["dep:getrandom"]
+serde1 = ["dep:serde"] # enables serde for BlockRng wrapper
 
 [dependencies]
 serde = { version = "1", features = ["derive"], optional = true }

rand_distr/Cargo.toml

@@ -29,7 +29,8 @@ alloc = ["rand/alloc"]
 # feature (default-enabled) will have the same effect.
 std_math = ["num-traits/std"]
 
-serde1 = ["serde", "rand/serde1"]
+serde1 = ["dep:serde", "rand/serde1"]
+serde_with = ["dep:serde_with"]
 
 [dependencies]
 rand = { path = "..", version = "=0.9.0-alpha.1", default-features = false }

rand_pcg/Cargo.toml

@@ -20,7 +20,7 @@ all-features = true
 rustdoc-args = ["--generate-link-to-definition"]
 
 [features]
-serde1 = ["serde"]
+serde1 = ["dep:serde"]
 getrandom = ["rand_core/getrandom"]
 
 [dependencies]