refactor(ws): Clarify what rust-version is used

For workflows like `cargo info`, this call will live on regardless of
what we do with the resolver.

Author: epage

src/cargo/core/workspace.rs

@@ -664,7 +664,7 @@ impl<'gctx> Workspace<'gctx> {
 
     /// Get the lowest-common denominator `package.rust-version` within the workspace, if specified
     /// anywhere
-    pub fn rust_version(&self) -> Option<&RustVersion> {
+    pub fn lowest_rust_version(&self) -> Option<&RustVersion> {
         self.members().filter_map(|pkg| pkg.rust_version()).min()
     }
 

src/cargo/ops/cargo_update.rs

@@ -739,7 +739,7 @@ fn required_rust_version(ws: &Workspace<'_>) -> Option<PartialVersion> {
         return None;
     }
 
-    if let Some(ver) = ws.rust_version() {
+    if let Some(ver) = ws.lowest_rust_version() {
         Some(ver.clone().into_partial())
     } else {
         let rustc = ws.gctx().load_global_rustc(Some(ws)).ok()?;

src/cargo/ops/lockfile.rs

@@ -71,7 +71,7 @@ pub fn write_pkg_lockfile(ws: &Workspace<'_>, resolve: &mut Resolve) -> CargoRes
     // out lock file updates as they're otherwise already updated, and changes
     // which don't touch dependencies won't seemingly spuriously update the lock
     // file.
-    let default_version = ResolveVersion::with_rust_version(ws.rust_version());
+    let default_version = ResolveVersion::with_rust_version(ws.lowest_rust_version());
     let current_version = resolve.version();
     let next_lockfile_bump = ws.gctx().cli_unstable().next_lockfile_bump;
     tracing::debug!("lockfile - current: {current_version:?}, default: {default_version:?}");

src/cargo/ops/registry/info/mod.rs

@@ -217,6 +217,6 @@ fn try_get_msrv_from_nearest_manifest_or_ws(
     let rust_version = nearest_package.and_then(|p| p.rust_version().map(|v| v.as_partial()));
     // If the nearest manifest does not have a specific Rust version, try to get it from the workspace.
     rust_version
-        .or_else(|| ws.and_then(|ws| ws.rust_version().map(|v| v.as_partial())))
+        .or_else(|| ws.and_then(|ws| ws.lowest_rust_version().map(|v| v.as_partial())))
         .cloned()
 }

src/cargo/ops/resolve.rs

@@ -357,7 +357,7 @@ pub fn resolve_with_previous<'gctx>(
         version_prefs.version_ordering(VersionOrdering::MinimumVersionsFirst)
     }
     if ws.resolve_honors_rust_version() {
-        let rust_version = if let Some(ver) = ws.rust_version() {
+        let rust_version = if let Some(ver) = ws.lowest_rust_version() {
             ver.clone().into_partial()
         } else {
             let rustc = ws.gctx().load_global_rustc(Some(ws))?;
@@ -422,7 +422,7 @@ pub fn resolve_with_previous<'gctx>(
         &replace,
         registry,
         &version_prefs,
-        ResolveVersion::with_rust_version(ws.rust_version()),
+        ResolveVersion::with_rust_version(ws.lowest_rust_version()),
         Some(ws.gctx()),
     )?;