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#!/bin/bash
# Check what rand/RngCore/Rng methods are called in random.rs
rg -n "\.next_u32\|\.next_u64\|\.fill_bytes\|\.gen\b\|\.random\b\|rand::Rng\|rand::RngCore\|rand_core" crates/stdlib/src/random.rs

Repository: RustPython/RustPython

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# Check if file exists and get the imports section
head -30 crates/stdlib/src/random.rs

Repository: RustPython/RustPython

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# Search more broadly for any 'use' statements and RNG variable usage
rg -A 5 -B 5 "use rand" crates/stdlib/src/random.rs

Repository: RustPython/RustPython

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# Look for where the RNG object is actually being used
rg -n "rng\|Rng\|RngCore" crates/stdlib/src/random.rs

Repository: RustPython/RustPython

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# Read the full file to understand RNG usage
cat -n crates/stdlib/src/random.rs | head -100

Repository: RustPython/RustPython

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# Search for method calls on 'rng' variable without escaping
rg -n "\brng\." crates/stdlib/src/random.rs

Repository: RustPython/RustPython

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# Check what MT19937 implements - search documentation or trait bounds
rg -n "MT19937" crates/stdlib/src/random.rs | head -20

Repository: RustPython/RustPython

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# Check if there are any compiler errors or clippy warnings in the repo
# Try to find cargo check or build output
cd crates/stdlib && cargo check 2>&1 | grep -A 5 -B 5 "random\|Rng\|error\|warning" | head -50

Repository: RustPython/RustPython

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# Search for MT19937::from_rng usage and documentation in mt19937 crate
rg -A 2 "from_rng" crates/stdlib/src/random.rs

Repository: RustPython/RustPython

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# Check what trait MT19937 implements by searching for impl statements
rg "impl.*MT19937\|impl.*for.*MT19937" --type rust

Repository: RustPython/RustPython

Length of output: 47

🌐 Web query:

mt19937 Rust crate from_rng method parameter trait

💡 Result:

In the rand_core-based Rust ecosystem, the MT19937 generator’s “from_rng” style constructor is exposed via the rand_core::SeedableRng trait as: fn from_rng<R: RngCore>(rng: R) -> Result<Self, Error> So the parameter is a type parameter R constrained by rand_core::RngCore (an RNG producing values without error), passed by value (rng: R) and returns Result<Self, Error>. This is the generic trait signature in rand_core’s SeedableRng: [1]. Common related (infallible) variant in rand_mt: rand_mt’s Mt implements a method with signature: fn from_rng(rng: &mut R) -> Self where R: Rng +?Sized Here the parameter is &mut R, where R: rand::Rng (the infallible high-level RNG trait), and the method returns Self directly. [2] For the “mt19937” crate specifically (coolreader18/hiroshima-univ translation), its source shows implementations of rand_core::TryRng and rand_core::SeedableRng for MT19937 (but the exact from_rng signature there follows the rand_core::SeedableRng trait; the trait provides from_rng generically). [3][4] Therefore, when you ask “mt19937 Rust crate from_rng method parameter trait”, the trait bound for from_rng is R: RngCore in rand_core::SeedableRng. [1] If instead you are referring to rand_mt’s Mt::from_rng convenience API, the parameter uses &mut R where R: rand::Rng +?Sized. [2]

Citations:

• 1: https://docs.rs/rand_core/0.4.0/rand_core/trait.SeedableRng.html
• 2: https://docs.rs/rand_mt/latest/rand_mt/struct.Mt.html
• 3: https://docs.rs/mt19937/latest/src/mt19937/lib.rs.html
• 4: https://docs.rs/rand_mt/latest/rand_mt/

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# Check if RngCore is imported elsewhere or re-exported
rg "RngCore\|rand_core" crates/stdlib/src/random.rs

Repository: RustPython/RustPython

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# Check if there's a re-export of RngCore in the rand crate imports
rg "use rand" crates/stdlib/src/random.rs -A 1 -B 1

Repository: RustPython/RustPython

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# Try to check Cargo.toml to see rand version and features
cat crates/stdlib/Cargo.toml | grep -A 5 -B 5 "rand"

Repository: RustPython/RustPython

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# Search for any build output or error logs
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Repository: RustPython/RustPython

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-    use rand::{Rng, SeedableRng};
+    use rand_core::RngCore;
+    use rand::SeedableRng;

or equivalently:

-    use rand::{Rng, SeedableRng};
+    use rand::{SeedableRng};
+    use rand_core::RngCore;