Extract & re-use filter_targets in cargo_compile

Also drop part of the docs in `list_rule_targets`, as that info is now on `Proposal`.

src/cargo/ops/cargo_compile.rs

@@ -619,24 +619,16 @@ fn generate_targets<'a>(
         } => {
             if lib {
                 let mut libs = Vec::new();
-                for pkg in packages {
-                    for target in pkg.targets().iter().filter(|t| t.is_lib()) {
-                        if build_config.mode == CompileMode::Doctest && !target.doctestable() {
-                            ws.config()
-                                .shell()
-                                .warn(format!(
-                                "doc tests are not supported for crate type(s) `{}` in package `{}`",
-                                target.rustc_crate_types().join(", "),
-                                pkg.name()
-                            ))?;
-                        } else {
-                            libs.push(Proposal {
-                                pkg,
-                                target,
-                                requires_features: false,
-                                mode: build_config.mode,
-                            });
-                        }
+                for proposal in filter_targets(packages, Target::is_lib, false, build_config.mode) {
+                    let Proposal { target, pkg, .. } = proposal;
+                    if build_config.mode == CompileMode::Doctest && !target.doctestable() {
+                        ws.config().shell().warn(format!(
+                            "doc tests are not supported for crate type(s) `{}` in package `{}`",
+                            target.rustc_crate_types().join(", "),
+                            pkg.name()
+                        ))?;
+                    } else {
+                        libs.push(proposal)
                     }
                 }
                 if !all_targets && libs.is_empty() {
@@ -655,7 +647,7 @@ fn generate_targets<'a>(
 
             // If --tests was specified, add all targets that would be
             // generated by `cargo test`.
-            let test_filter = match *tests {
+            let test_filter = match tests {
                 FilterRule::All => Target::tested,
                 FilterRule::Just(_) => Target::is_test,
             };
@@ -666,7 +658,7 @@ fn generate_targets<'a>(
             };
             // If --benches was specified, add all targets that would be
             // generated by `cargo bench`.
-            let bench_filter = match *benches {
+            let bench_filter = match benches {
                 FilterRule::All => Target::benched,
                 FilterRule::Just(_) => Target::is_bench,
             };
@@ -795,36 +787,22 @@ fn filter_default_targets(targets: &[Target], mode: CompileMode) -> Vec<&Target>
     }
 }
 
-/// Returns a list of targets based on command-line target selection flags.
-/// The return value is a list of `(Package, Target, bool, CompileMode)`
-/// tuples.  The `bool` value indicates whether or not all required features
-/// *must* be present.
+/// Returns a list of proposed targets based on command-line target selection flags.
 fn list_rule_targets<'a>(
     packages: &[&'a Package],
     rule: &FilterRule,
     target_desc: &'static str,
     is_expected_kind: fn(&Target) -> bool,
     mode: CompileMode,
 ) -> CargoResult<Vec<Proposal<'a>>> {
-    let mut result = Vec::new();
-    match *rule {
+    let mut proposals = Vec::new();
+    match rule {
         FilterRule::All => {
-            for pkg in packages {
-                for target in pkg.targets() {
-                    if is_expected_kind(target) {
-                        result.push(Proposal {
-                            pkg,
-                            target,
-                            requires_features: false,
-                            mode,
-                        });
-                    }
-                }
-            }
+            proposals.extend(filter_targets(packages, is_expected_kind, false, mode))
         }
-        FilterRule::Just(ref names) => {
+        FilterRule::Just(names) => {
             for name in names {
-                result.extend(find_named_targets(
+                proposals.extend(find_named_targets(
                     packages,
                     name,
                     target_desc,
@@ -834,7 +812,7 @@ fn list_rule_targets<'a>(
             }
         }
     }
-    Ok(result)
+    Ok(proposals)
 }
 
 /// Find the targets for a specifically named target.
@@ -845,20 +823,9 @@ fn find_named_targets<'a>(
     is_expected_kind: fn(&Target) -> bool,
     mode: CompileMode,
 ) -> CargoResult<Vec<Proposal<'a>>> {
-    let mut result = Vec::new();
-    for pkg in packages {
-        for target in pkg.targets() {
-            if target.name() == target_name && is_expected_kind(target) {
-                result.push(Proposal {
-                    pkg,
-                    target,
-                    requires_features: true,
-                    mode,
-                });
-            }
-        }
-    }
-    if result.is_empty() {
+    let filter = |t: &Target| t.name() == target_name && is_expected_kind(t);
+    let proposals = filter_targets(packages, filter, true, mode);
+    if proposals.is_empty() {
         let suggestion = packages
             .iter()
             .flat_map(|pkg| {
@@ -880,5 +847,25 @@ fn find_named_targets<'a>(
             None => failure::bail!("no {} target named `{}`", target_desc, target_name),
         }
     }
-    Ok(result)
+    Ok(proposals)
+}
+
+fn filter_targets<'a>(
+    packages: &[&'a Package],
+    predicate: impl Fn(&Target) -> bool,
+    requires_features: bool,
+    mode: CompileMode,
+) -> Vec<Proposal<'a>> {
+    let mut proposals = Vec::new();
+    for pkg in packages {
+        for target in pkg.targets().iter().filter(|t| predicate(t)) {
+            proposals.push(Proposal {
+                pkg,
+                target,
+                requires_features,
+                mode,
+            });
+        }
+    }
+    proposals
 }