Style warnings more prominently

src/display/style.rs

@@ -426,6 +426,24 @@ fn apply_header_color(
     }
 }
 
+/// Style `s` as a warning and write to stderr.
+pub(crate) fn print_warning(s: &str, display_options: &DisplayOptions) {
+    let prefix = if display_options.use_color {
+        if display_options.background_color.is_dark() {
+            "warning: ".bright_yellow().to_string()
+        } else {
+            "warning: ".yellow().to_string()
+        }
+        .bold()
+        .to_string()
+    } else {
+        "warning: ".to_string()
+    };
+
+    eprint!("{}", prefix);
+    eprint!("{}\n\n", s);
+}
+
 pub(crate) fn apply_line_number_color(
     s: &str,
     is_novel: bool,

src/main.rs

@@ -44,6 +44,7 @@ mod words;
 #[macro_use]
 extern crate log;
 
+use display::style::print_warning;
 use log::info;
 use mimalloc::MiMalloc;
 
@@ -228,9 +229,12 @@ fn main() {
                     _ => false,
                 };
 
-                eprintln!(
-                    "warning: You've specified the same {} twice.\n",
-                    if is_dir { "directory" } else { "file" }
+                print_warning(
+                    &format!(
+                        "You've specified the same {} twice.",
+                        if is_dir { "directory" } else { "file" }
+                    ),
+                    &display_options,
                 );
             }
 
@@ -402,9 +406,12 @@ fn diff_conflicts_file(
     };
 
     if conflict_files.num_conflicts == 0 {
-        eprintln!(
-            "warning: Expected a file with conflict markers {}, but none were found. See --help for usage instructions.\n",
-            START_LHS_MARKER,
+        print_warning(
+            &format!(
+                "Expected a file with conflict markers {}, but none were found. See --help for usage instructions.",
+                START_LHS_MARKER,
+            ),
+            display_options,
         );
     }