cargo clean -p package can clear the document of a single crates

src/cargo/core/compiler/layout.rs

@@ -125,6 +125,8 @@ pub struct Layout {
     examples: PathBuf,
     /// The directory for rustdoc output: `$root/doc`
     doc: PathBuf,
+    /// The directory for rustdoc output: `$root/doc/src`
+    src: PathBuf,
     /// The directory for temporary data of integration tests and benches: `$dest/tmp`
     tmp: PathBuf,
     /// The lockfile for a build (`.cargo-lock`). Will be unlocked when this
@@ -172,6 +174,7 @@ impl Layout {
             fingerprint: dest.join(".fingerprint"),
             examples: dest.join("examples"),
             doc: root.join("doc"),
+            src: root.join("doc/src"),
             tmp: root.join("tmp"),
             root,
             dest,
@@ -206,6 +209,10 @@ impl Layout {
     pub fn doc(&self) -> &Path {
         &self.doc
     }
+    /// Fetch the doc/src path.
+    pub fn src(&self) -> &Path {
+        &self.src
+    }
     /// Fetch the root path (`/…/target`).
     pub fn root(&self) -> &Path {
         &self.root

src/cargo/ops/cargo_clean.rs

@@ -136,9 +136,13 @@ pub fn clean(ws: &Workspace<'_>, opts: &CleanOptions<'_>) -> CargoResult<()> {
     for pkg in packages {
         let pkg_dir = format!("{}-*", pkg.name());
 
-        // Clean fingerprints.
         for (_, layout) in &layouts_with_host {
+            // Clean fingerprints.
             rm_rf_glob(&layout.fingerprint().join(&pkg_dir), config)?;
+            // Clean target/doc.
+            rm_rf(&layout.doc(), config)?;
+            // Clean target/doc/src.
+            rm_rf(&layout.src(), config)?;
         }
 
         for target in pkg.targets() {

tests/testsuite/clean.rs

@@ -549,3 +549,32 @@ fn clean_spec_reserved() {
         )
         .run();
 }
+
+#[cargo_test]
+fn clean_spec_doc() {
+    // `clean -p package` make target/doc/package clear
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+                [package]
+                name = "foo"
+                version = "0.0.1"
+                authors = []
+            "#,
+        )
+        .file("src/main.rs", "fn main() {}")
+        .build();
+
+    p.cargo("doc").run();
+
+    let doc_path = &p.build_dir().join("doc");
+    assert!(doc_path.is_dir());
+
+    p.cargo("clean -p foo").run();
+
+    assert!(!doc_path.join("foo").is_dir());
+    assert!(!doc_path.join("src").join("foo").is_dir());
+
+    assert!(p.build_dir().is_dir());
+}