Correctly handle line comments in attributes

Author: GuillaumeGomez

src/librustdoc/doctest/make.rs

@@ -176,9 +176,18 @@ impl DocTestBuilder {
 
         // Now push any outer attributes from the example, assuming they
         // are intended to be crate attributes.
-        prog.push_str(&self.crate_attrs);
-        prog.push_str(&self.maybe_crate_attrs);
-        prog.push_str(&self.crates);
+        if !self.crate_attrs.is_empty() {
+            prog.push_str(&self.crate_attrs);
+            prog.push('\n');
+        }
+        if !self.maybe_crate_attrs.is_empty() {
+            prog.push_str(&self.maybe_crate_attrs);
+            prog.push('\n');
+        }
+        if !self.crates.is_empty() {
+            prog.push_str(&self.crates);
+            prog.push('\n');
+        }
 
         // Don't inject `extern crate std` because it's already injected by the
         // compiler.

src/librustdoc/doctest/tests.rs

@@ -197,6 +197,8 @@ fn make_test_crate_attrs() {
 assert_eq!(2+2, 4);";
     let expected = "#![allow(unused)]
 #![feature(sick_rad)]
+
+
 fn main() {
 assert_eq!(2+2, 4);
 }"
@@ -401,3 +403,26 @@ fn check_split_args() {
     compare("a\n\t \rb", &["a", "b"]);
     compare("a\n\t1 \rb", &["a", "1", "b"]);
 }
+
+#[test]
+fn comment_in_attrs() {
+    // if input already has a fn main, it should insert a space before it
+    let opts = default_global_opts("");
+    let input = "\
+#![feature(rustdoc_internals)]
+#![allow(internal_features)]
+#![doc(rust_logo)]
+//! This crate has the Rust(tm) branding on it.";
+    let expected = "\
+#![allow(unused)]
+#![feature(rustdoc_internals)]
+#![allow(internal_features)]
+#![doc(rust_logo)]
+//! This crate has the Rust(tm) branding on it.
+fn main() {
+
+}"
+    .to_string();
+    let (output, len) = make_test(input, None, false, &opts, None);
+    assert_eq!((output, len), (expected, 2));
+}