diff --git a/lib/std/Build.zig b/lib/std/Build.zig
index 2c9427645f71b3285f80115b8248de4add324a77..d6b63b59a0617daa18fa3494b61688b050528b81 100644
--- a/lib/std/Build.zig
+++ b/lib/std/Build.zig
@@ -2567,6 +2567,16 @@ pub const LazyPath = union(enum) {
         return dupeInner(lazy_path, graph.arena);
     }
 
+    /// Copies the slice of paths and all internal strings.
+    ///
+    /// The `graph` parameter is only used for the global arena allocator.
+    pub fn dupeList(lazy_paths: []const LazyPath, graph: *const Graph) []const LazyPath {
+        const arena = graph.arena;
+        const result = graph.alloc(LazyPath, lazy_paths.len);
+        for (result, lazy_paths) |*d, s| d.* = dupeInner(s, arena);
+        return result;
+    }
+
     fn dupeInner(lazy_path: LazyPath, arena: Allocator) LazyPath {
         return switch (lazy_path) {
             .src_path => |sp| .{ .src_path = .{ .owner = sp.owner, .sub_path = sp.owner.dupePath(sp.sub_path) } },
diff --git a/lib/std/Build/Module.zig b/lib/std/Build/Module.zig
index 5583b6611b474c8fe07fd5f77492967a532d5edd..f8996ccad050ea9b542a6f37b470a9c33ceb335d 100644
--- a/lib/std/Build/Module.zig
+++ b/lib/std/Build/Module.zig
@@ -146,13 +146,10 @@ pub const RcSourceFile = struct {
     include_paths: []const LazyPath = &.{},
 
     pub fn dupe(file: RcSourceFile, graph: *const std.Build.Graph) RcSourceFile {
-        const arena = graph.arena;
-        const include_paths = arena.alloc(LazyPath, file.include_paths.len) catch @panic("OOM");
-        for (include_paths, file.include_paths) |*dest, lazy_path| dest.* = lazy_path.dupe(graph);
         return .{
             .file = file.file.dupe(graph),
             .flags = graph.dupeStrings(file.flags),
-            .include_paths = include_paths,
+            .include_paths = LazyPath.dupeList(file.include_paths, graph),
         };
     }
 };
diff --git a/lib/std/Build/Step/Fmt.zig b/lib/std/Build/Step/Fmt.zig
index 294afdb9af1c23b1500598afe3f1c4bbc68080a7..4052e21bd08c0c43e66f4e1bae94991f5fcc6b00 100644
--- a/lib/std/Build/Step/Fmt.zig
+++ b/lib/std/Build/Step/Fmt.zig
@@ -34,8 +34,8 @@ pub fn create(owner: *std.Build, options: Options) *Fmt {
             .name = if (options.check) "zig fmt --check" else "zig fmt",
             .owner = owner,
         }),
-        .paths = options.paths,
-        .exclude_paths = options.exclude_paths,
+        .paths = LazyPath.dupeList(options.paths, graph),
+        .exclude_paths = LazyPath.dupeList(options.exclude_paths, graph),
         .check = options.check,
     };