What causes "{} target {}.name is required" in rust-lang/cargo?

Add an explicit `name = "..."` to the target table.

target .name is required

Error message

{} target {}.name is required

What it means

For explicitly declared targets (`[[bin]]`, `[[test]]`, `[[bench]]`, `[[example]]`), the `name` field is mandatory — there is no inference for listed tables. `validate_target_name` hits the `None` arm at targets.rs:1190-1194 and bails. (Auto-inferred targets like the default `src/main.rs` bin bypass this path.)

Solutions

Add an explicit `name = "..."` to the target table.
Alternatively, rely on file-based discovery (place the binary at `src/bin/foo.rs`) instead of a `[[bin]]` table.

Example fix

# before
[[bin]]
path = "src/server.rs"

# after
[[bin]]
name = "server"
path = "src/server.rs"

Defensive patterns

Strategy: validation

Validate before calling

fn explicit_targets_have_name(tables: &[Option<&str>]) -> bool {
    tables.iter().all(|t| t.is_some())
}
// every [[bin]]/[[test]]/[[bench]]/[[example]] table must carry a `name`

Prevention

Always set `name` on explicitly listed target tables.
Prefer file-based discovery (`src/bin/foo.rs`) when name inference is wanted.
Lint manifests for nameless target tables.

When it happens

Trigger: A `[[bin]]` (or `[[test]]`/`[[bench]]`/`[[example]]`) table with no `name` key. The `match target.name` falls through to `None`.

Common situations: Adding a `[[bin]]` table to set only `path` and forgetting `name`. Truncated copy-paste of a target block. Tutorials that omit the name field.

Related errors

AI-assisted analysis of rust-lang/cargo@eb98b54bc9 (2026-08-11). Data as JSON: /api/errors/f09ae8e64de87448. Report an issue: GitHub.

Appendix: source

Thrown at src/workspace/parser/targets.rs:1190

    target: &TomlTarget,
    target_kind_human: &str,
    target_kind: &str,
    warnings: &mut Vec<String>,
) -> CargoResult<()> {
    match target.name {
        Some(ref name) => {
            if name.trim().is_empty() {
                anyhow::bail!("{} target names cannot be empty", target_kind_human)
            }
            if cfg!(windows) && restricted_names::is_windows_reserved(name) {
                warnings.push(format!(
                    "{} target `{}` is a reserved Windows filename, \
                        this target will not work on Windows platforms",
                    target_kind_human, name
                ));
            }
        }
        None => anyhow::bail!(
            "{} target {}.name is required",
            target_kind_human,
            target_kind
        ),
    }

    Ok(())
}

fn validate_bin_proc_macro(
    target: &TomlTarget,
    edition: Edition,
    warnings: &mut Vec<String>,
    errors: &mut Vec<String>,
) -> CargoResult<()> {
    if target.proc_macro() == Some(true) {
        let name = name_or_panic(target);
        errors.push(format!(

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