Remove conflict between flatten and skip

serde_derive/src/de.rs

@@ -2456,7 +2456,7 @@ fn deserialize_map(
 
     let extract_collected = fields_names
         .iter()
-        .filter(|&&(field, _)| field.attrs.flatten())
+        .filter(|&&(field, _)| field.attrs.flatten() && !field.attrs.skip_deserializing())
         .map(|&(field, ref name)| {
             let field_ty = field.ty;
             let func = match field.attrs.deserialize_with() {

serde_derive/src/internals/check.rs

@@ -76,25 +76,6 @@ fn check_flatten_field(cx: &Ctxt, style: Style, field: &Field) {
         }
         _ => {}
     }
-    if field.attrs.skip_serializing() {
-        cx.error_spanned_by(
-            field.original,
-            "#[serde(flatten)] can not be combined with \
-             #[serde(skip_serializing)]",
-        );
-    } else if field.attrs.skip_serializing_if().is_some() {
-        cx.error_spanned_by(
-            field.original,
-            "#[serde(flatten)] can not be combined with \
-             #[serde(skip_serializing_if = \"...\")]",
-        );
-    } else if field.attrs.skip_deserializing() {
-        cx.error_spanned_by(
-            field.original,
-            "#[serde(flatten)] can not be combined with \
-             #[serde(skip_deserializing)]",
-        );
-    }
 }
 
 /// The `other` attribute must be used at most once and it must be the last

test_suite/tests/test_gen.rs

@@ -665,6 +665,25 @@ fn test_gen() {
         ty: &'a str,
         id: String,
     }
+
+    #[derive(Serialize, Deserialize)]
+    struct FlattenSkipSerializing<T> {
+        #[serde(flatten, skip_serializing)]
+        #[allow(dead_code)]
+        flat: T,
+    }
+
+    #[derive(Serialize, Deserialize)]
+    struct FlattenSkipSerializingIf<T> {
+        #[serde(flatten, skip_serializing_if = "StdOption::is_none")]
+        flat: StdOption<T>,
+    }
+
+    #[derive(Serialize, Deserialize)]
+    struct FlattenSkipDeserializing<T> {
+        #[serde(flatten, skip_deserializing)]
+        flat: T,
+    }
 }
 
 //////////////////////////////////////////////////////////////////////////

test_suite/tests/ui/conflict/flatten-skip-deserializing.rs

@@ -1,14 +0,0 @@
-use serde_derive::Deserialize;
-
-#[derive(Deserialize)]
-struct Foo {
-    #[serde(flatten, skip_deserializing)]
-    other: Other,
-}
-
-#[derive(Deserialize)]
-struct Other {
-    x: u32,
-}
-
-fn main() {}

test_suite/tests/ui/conflict/flatten-skip-deserializing.stderr

@@ -1,9 +0,0 @@
-error: #[serde(flatten)] can not be combined with #[serde(skip_deserializing)]
- --> $DIR/flatten-skip-deserializing.rs:5:5
-  |
-5 | /     #[serde(flatten, skip_deserializing)]
-6 | |     other: Other,
-  | |________________^
-
-error: aborting due to previous error
-

test_suite/tests/ui/conflict/flatten-skip-serializing-if.rs

@@ -1,14 +0,0 @@
-use serde_derive::Serialize;
-
-#[derive(Serialize)]
-struct Foo {
-    #[serde(flatten, skip_serializing_if = "Option::is_none")]
-    other: Option<Other>,
-}
-
-#[derive(Serialize)]
-struct Other {
-    x: u32,
-}
-
-fn main() {}

test_suite/tests/ui/conflict/flatten-skip-serializing-if.stderr

@@ -1,9 +0,0 @@
-error: #[serde(flatten)] can not be combined with #[serde(skip_serializing_if = "...")]
- --> $DIR/flatten-skip-serializing-if.rs:5:5
-  |
-5 | /     #[serde(flatten, skip_serializing_if = "Option::is_none")]
-6 | |     other: Option<Other>,
-  | |________________________^
-
-error: aborting due to previous error
-

test_suite/tests/ui/conflict/flatten-skip-serializing.rs

@@ -1,14 +0,0 @@
-use serde_derive::Serialize;
-
-#[derive(Serialize)]
-struct Foo {
-    #[serde(flatten, skip_serializing)]
-    other: Other,
-}
-
-#[derive(Serialize)]
-struct Other {
-    x: u32,
-}
-
-fn main() {}

test_suite/tests/ui/conflict/flatten-skip-serializing.stderr

@@ -1,9 +0,0 @@
-error: #[serde(flatten)] can not be combined with #[serde(skip_serializing)]
- --> $DIR/flatten-skip-serializing.rs:5:5
-  |
-5 | /     #[serde(flatten, skip_serializing)]
-6 | |     other: Other,
-  | |________________^
-
-error: aborting due to previous error
-