Do not ignore --features when --all-features is present

src/cargo/core/resolver/dep_cache.rs

@@ -323,14 +323,14 @@ fn build_requirements<'a, 'b: 'a>(
                         return Err(e.into_activate_error(parent, s));
                     }
                 }
-            } else {
-                for fv in features.iter() {
-                    if let Err(e) = reqs.require_value(fv) {
-                        return Err(e.into_activate_error(parent, s));
-                    }
+            }
+
+            for fv in features.iter() {
+                if let Err(e) = reqs.require_value(fv) {
+                    return Err(e.into_activate_error(parent, s));
                 }
-                handle_default(*uses_default_features, &mut reqs)?;
             }
+            handle_default(*uses_default_features, &mut reqs)?;
         }
         RequestedFeatures::DepFeatures {
             features,

src/cargo/core/resolver/features.rs

@@ -680,19 +680,18 @@ impl<'a, 'cfg> FeatureResolver<'a, 'cfg> {
     ) -> Vec<FeatureValue> {
         let summary = self.resolve.summary(pkg_id);
         let feature_map = summary.features();
+
+        let mut result: Vec<FeatureValue> = cli_features.features.iter().cloned().collect();
+        let default = InternedString::new("default");
+        if cli_features.uses_default_features && feature_map.contains_key(&default) {
+            result.push(FeatureValue::Feature(default));
+        }
+
         if cli_features.all_features {
-            feature_map
-                .keys()
-                .map(|k| FeatureValue::Feature(*k))
-                .collect()
-        } else {
-            let mut result: Vec<FeatureValue> = cli_features.features.iter().cloned().collect();
-            let default = InternedString::new("default");
-            if cli_features.uses_default_features && feature_map.contains_key(&default) {
-                result.push(FeatureValue::Feature(default));
-            }
-            result
+            result.extend(feature_map.keys().map(|k| FeatureValue::Feature(*k)))
         }
+
+        result
     }
 
     /// Returns the dependencies for a package, filtering out inactive targets.

src/cargo/core/workspace.rs

@@ -1117,7 +1117,7 @@ impl<'cfg> Workspace<'cfg> {
         cli_features: &CliFeatures,
         found_features: &mut BTreeSet<FeatureValue>,
     ) -> CliFeatures {
-        if cli_features.features.is_empty() || cli_features.all_features {
+        if cli_features.features.is_empty() {
             return cli_features.clone();
         }
 
@@ -1185,7 +1185,7 @@ impl<'cfg> Workspace<'cfg> {
         }
         CliFeatures {
             features: Rc::new(features),
-            all_features: false,
+            all_features: cli_features.all_features,
             uses_default_features: cli_features.uses_default_features,
         }
     }

src/cargo/ops/tree/graph.rs

@@ -473,12 +473,12 @@ fn add_cli_features(
     let mut to_add: HashSet<FeatureValue> = HashSet::new();
     if cli_features.all_features {
         to_add.extend(feature_map.keys().map(|feat| FeatureValue::Feature(*feat)));
-    } else {
-        if cli_features.uses_default_features {
-            to_add.insert(FeatureValue::Feature(InternedString::new("default")));
-        }
-        to_add.extend(cli_features.features.iter().cloned());
-    };
+    }
+
+    if cli_features.uses_default_features {
+        to_add.insert(FeatureValue::Feature(InternedString::new("default")));
+    }
+    to_add.extend(cli_features.features.iter().cloned());
 
     // Add each feature as a node, and mark as "from command-line" in graph.cli_features.
     for fv in to_add {

tests/testsuite/features2.rs

@@ -2398,3 +2398,77 @@ foo v0.1.0 [..]
         )
         .run();
 }
+
+#[cargo_test]
+fn all_features_merges_with_features() {
+    Package::new("dep", "0.1.0")
+        .feature("feat1", &[])
+        .file(
+            "src/lib.rs",
+            r#"
+                #[cfg(feature="feat1")]
+                pub fn work() {
+                    println!("it works");
+                }
+            "#,
+        )
+        .publish();
+
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+                [package]
+                name = "foo"
+                version = "0.1.0"
+                edition = "2018"
+
+                [features]
+                a = []
+
+                [dependencies]
+                dep = "0.1"
+
+                [[example]]
+                name = "ex"
+                required-features = ["a", "dep/feat1"]
+            "#,
+        )
+        .file(
+            "examples/ex.rs",
+            r#"
+            fn main() {
+                dep::work();
+            }
+            "#,
+        )
+        .file("src/lib.rs", "")
+        .build();
+
+    p.cargo("run --example ex --all-features --features dep/feat1")
+        .with_stderr(
+            "\
+[UPDATING] [..]
+[DOWNLOADING] crates ...
+[DOWNLOADED] [..]
+[COMPILING] dep v0.1.0
+[COMPILING] foo v0.1.0 [..]
+[FINISHED] [..]
+[RUNNING] `target/debug/examples/ex[EXE]`
+",
+        )
+        .with_stdout("it works")
+        .run();
+
+    switch_to_resolver_2(&p);
+
+    p.cargo("run --example ex --all-features --features dep/feat1")
+        .with_stderr(
+            "\
+[FINISHED] [..]
+[RUNNING] `target/debug/examples/ex[EXE]`
+",
+        )
+        .with_stdout("it works")
+        .run();
+}

tests/testsuite/features_namespaced.rs

@@ -849,7 +849,8 @@ foo v0.1.0 ([ROOT]/foo)
 bar v1.0.0
 └── bar feature \"default\"
     └── foo v0.1.0 ([ROOT]/foo)
-        └── foo feature \"a\" (command-line)
+        ├── foo feature \"a\" (command-line)
+        └── foo feature \"default\" (command-line)
 ",
         )
         .run();

tests/testsuite/tree_graph_features.rs

@@ -275,6 +275,7 @@ foo v0.1.0 ([..]/foo)
 opt2 v1.0.0
 └── opt2 feature \"default\"
     └── foo v0.1.0 ([..]/foo)
+        ├── foo feature \"default\" (command-line)
         ├── foo feature \"f1\" (command-line)
         │   └── foo feature \"f2\" (command-line)
         ├── foo feature \"f2\" (command-line)