Auto merge of #7340 - varkor:ignore-must_use-results, r=alexcrichton

Explicitly ignore some results

Use `let _ = ` to ignore some values that are `#[must_use]` when checking nested data types. This is necessary to compile cargo without warnings under rust-lang/rust#62262.

Author: bors

src/bin/cargo/commands/fetch.rs

@@ -30,6 +30,6 @@ pub fn exec(config: &mut Config, args: &ArgMatches<'_>) -> CliResult {
         config,
         target: args.target(),
     };
-    ops::fetch(&ws, &opts)?;
+    let _ = ops::fetch(&ws, &opts)?;
     Ok(())
 }

src/cargo/ops/cargo_package.rs

@@ -44,7 +44,7 @@ static VCS_INFO_FILE: &str = ".cargo_vcs_info.json";
 pub fn package(ws: &Workspace<'_>, opts: &PackageOpts<'_>) -> CargoResult<Option<FileLock>> {
     if ws.root().join("Cargo.lock").exists() {
         // Make sure the Cargo.lock is up-to-date and valid.
-        ops::resolve_ws(ws)?;
+        let _ = ops::resolve_ws(ws)?;
         // If Cargo.lock does not exist, it will be generated by `build_lock`
         // below, and will be validated during the verification step.
     }