synstructure 0.14.0

# This file is automatically @generated by Cargo.
# It is not intended for manual editing.
version = 4

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version = "1.0.0"
dependencies = [
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]

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[package]
name = "sample-synstructure"
version = "1.0.0"
edition = "2021"
publish = false

[dependencies]
synstructure = "=0.14.0"
syn = { version = "=3.0.6", features = ["derive", "parsing", "printing", "clone-impls", "extra-traits"] }
quote = "=1.0.47"
proc-macro2 = "=1.0.107"

[[bin]]
name = "contract"
path = "test/contract.rs"

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify pkg:cargo/synstructure@0.14.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:cargo/synstructure@0.14.0

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:8106a8bd857fae4833482573989e79789777ac7cf34ec2061c38cee682aec26b","contract":["Structure::new creates a structure AST from DeriveInput for structs and enums","Structure::each iterates over fields and generates pattern matching arm expressions","Structure::fold aggregates field expressions across variants with initial values","Structure::filter omits designated fields from match arm patterns","Structure::gen_impl generates trait implementation blocks with derived bounds"],"goal":"verify pkg:cargo/synstructure@0.14.0","kind":"HOW","packages":["pkg:cargo/synstructure@0.14.0"],"schemaVersion":1},"contractCommand":["cargo","run","--offline"],"environment":{"arch":"x64","distro":"alpine","ecosystem":"cargo","libc":"musl","os":"linux","packageManager":"cargo","schemaVersion":1},"license":"MIT-0","packages":["pkg:cargo/synstructure@0.14.0"],"schemaVersion":1,"subject":"pkg:cargo/synstructure@0.14.0","verifierAdapter":"cargo@1"}

{
  "schemaVersion": 1,
  "goal": "verify pkg:cargo/synstructure@0.14.0",
  "kind": "HOW",
  "packages": [
    "pkg:cargo/synstructure@0.14.0"
  ]
}

//! Clean-room verification sample for synstructure.

pub use synstructure::*;

use synstructure::Structure;
use quote::quote;

fn main() {
    // 1. Structure::new creates a structure AST from DeriveInput for structs and enums
    let di_struct: syn::DeriveInput = syn::parse_quote! {
        struct Point {
            x: i32,
            y: i32,
        }
    };
    let s_struct = Structure::new(&di_struct);
    assert_eq!(s_struct.variants().len(), 1);
    assert_eq!(s_struct.variants()[0].bindings().len(), 2);
    assert_eq!(s_struct.variants()[0].bindings()[0].ast().ident.as_ref().unwrap(), "x");
    assert_eq!(s_struct.variants()[0].bindings()[1].ast().ident.as_ref().unwrap(), "y");

    let di_enum: syn::DeriveInput = syn::parse_quote! {
        enum Choice {
            First(i32),
            Second(String, bool),
            Empty,
        }
    };
    let s_enum = Structure::new(&di_enum);
    assert_eq!(s_enum.variants().len(), 3);
    assert_eq!(s_enum.variants()[0].ast().ident, "First");
    assert_eq!(s_enum.variants()[0].bindings().len(), 1);
    assert_eq!(s_enum.variants()[1].ast().ident, "Second");
    assert_eq!(s_enum.variants()[1].bindings().len(), 2);
    assert_eq!(s_enum.variants()[2].ast().ident, "Empty");
    assert_eq!(s_enum.variants()[2].bindings().len(), 0);

    // 2. Structure::each iterates over fields and generates pattern matching arm expressions
    let each_tokens = s_struct.each(|bi| {
        quote!(check(#bi);)
    });
    let each_str = each_tokens.to_string();
    assert!(each_str.contains("Point"));
    assert!(each_str.contains("ref __binding_0"));
    assert!(each_str.contains("ref __binding_1"));
    assert!(each_str.contains("check (__binding_0) ;"));
    assert!(each_str.contains("check (__binding_1) ;"));

    // 3. Structure::fold aggregates field expressions across variants with initial values
    let fold_tokens = s_struct.fold(quote!(0), |acc, bi| {
        quote!(#acc + size_of_val(#bi))
    });
    let fold_str = fold_tokens.to_string();
    assert!(fold_str.contains("0 + size_of_val (__binding_0) + size_of_val (__binding_1)"));

    // 4. Structure::filter omits designated fields from match arm patterns
    let mut s_filtered = Structure::new(&di_struct);
    s_filtered.filter(|bi| {
        bi.ast().ident.as_ref().map_or(false, |ident| ident == "x")
    });
    assert!(s_filtered.variants()[0].omitted_bindings());
    assert_eq!(s_filtered.variants()[0].bindings().len(), 1);
    let pat_str = s_filtered.variants()[0].pat().to_string();
    assert!(pat_str.contains("x : ref __binding_0"));
    assert!(pat_str.contains(".."));
    assert!(!pat_str.contains("y :"));

    // 5. Structure::gen_impl generates trait implementation blocks with derived bounds
    let di_generic: syn::DeriveInput = syn::parse_quote! {
        struct Container<T> {
            item: T,
        }
    };
    let s_generic = Structure::new(&di_generic);
    let impl_tokens = s_generic.gen_impl(quote! {
        gen impl custom_crate::CustomTrait for @Self {
            fn custom_fn(&self) {}
        }
    });
    let impl_str = impl_tokens.to_string();
    assert!(impl_str.contains("custom_crate :: CustomTrait for Container < T >"));
    assert!(impl_str.contains("where T : custom_crate :: CustomTrait"));
    assert!(impl_str.contains("fn custom_fn (& self) { }"));

    println!("All synstructure contract assertions passed successfully.");
}