Generalise Validation::and, rename original to ::_and

For a future change we need a version that gives access to the Success value from both arguments.

Author: infinisil

src/eval.rs

@@ -372,7 +372,7 @@ fn by_name(
 
             // Independently report problems about whether it's a derivation and the callPackage
             // variant.
-            is_derivation_result.and(variant_result)
+            is_derivation_result.and_(variant_result)
         }
     };
     Ok(

src/structure.rs

@@ -96,7 +96,7 @@ pub fn check_structure(
                         .into()
                     });
 
-                let result = result.and(validation::sequence_(duplicate_results));
+                let result = result.and_(validation::sequence_(duplicate_results));
 
                 let package_results = entries
                     .into_iter()
@@ -111,7 +111,7 @@ pub fn check_structure(
                     })
                     .collect_vec()?;
 
-                result.and(validation::sequence(package_results))
+                result.and_(validation::sequence(package_results))
             })
         })
         .collect_vec()?;
@@ -147,7 +147,7 @@ fn check_package(
         };
 
         let correct_relative_package_dir = relative_dir_for_package(&package_name);
-        let result = result.and(if relative_package_dir != correct_relative_package_dir {
+        let result = result.and_(if relative_package_dir != correct_relative_package_dir {
             // Only show this error if we have a valid shard and package name.
             // If one of those is wrong, you should fix that first.
             if shard_name_valid && package_name_valid {
@@ -164,15 +164,15 @@ fn check_package(
         });
 
         let package_nix_path = package_path.join(PACKAGE_NIX_FILENAME);
-        let result = result.and(if !package_nix_path.exists() {
+        let result = result.and_(if !package_nix_path.exists() {
             npv_143::PackageNixMissing::new(package_name.clone()).into()
         } else if !package_nix_path.is_file() {
             npv_144::PackageNixIsNotFile::new(package_name.clone()).into()
         } else {
             Success(())
         });
 
-        let result = result.and(references::check_references(
+        let result = result.and_(references::check_references(
             nix_file_store,
             &relative_package_dir,
             &relative_package_dir.to_path(path),

src/validation.rs

@@ -75,9 +75,17 @@ impl<A> Validation<A> {
 impl Validation<()> {
     /// Combine two validations, both of which need to be successful for the return value to be
     /// successful. The `Problem`s of both sides are returned concatenated.
-    pub fn and<A>(self, other: Validation<A>) -> Validation<A> {
+    pub fn and_<B>(self, other: Validation<B>) -> Validation<B> {
+        self.and(other, |(), b| b)
+    }
+}
+
+impl<A> Validation<A> {
+    /// Combine two validations, both of which need to be successful for the return value to be
+    /// successful. The `Problem`s of both sides are returned concatenated.
+    pub fn and<B, C, F: FnOnce(A, B) -> C>(self, other: Validation<B>, f: F) -> Validation<C> {
         match (self, other) {
-            (Success(_), Success(right_value)) => Success(right_value),
+            (Success(a), Success(b)) => Success(f(a, b)),
             (Failure(errors_l), Failure(errors_r)) => Failure(concat([errors_l, errors_r])),
             (Failure(errors), Success(_)) | (Success(_), Failure(errors)) => Failure(errors),
         }