diff --git a/src/Module.zig b/src/Module.zig
index 81a9ec220b..9ab2a859f8 100644
--- a/src/Module.zig
+++ b/src/Module.zig
@@ -4478,9 +4478,17 @@ pub fn semaFile(mod: *Module, file: *File) SemaError!void {
                 try reportRetryableFileError(mod, file, "unable to load source: {s}", .{@errorName(err)});
                 return error.AnalysisFail;
             };
-            const resolved_path = try file.pkg.root_src_directory.join(gpa, &.{
-                file.sub_file_path,
-            });
+
+            const resolved_path = std.fs.path.resolve(
+                gpa,
+                if (file.pkg.root_src_directory.path) |pkg_path|
+                    &[_][]const u8{ pkg_path, file.sub_file_path }
+                else
+                    &[_][]const u8{file.sub_file_path},
+            ) catch |err| {
+                try reportRetryableFileError(mod, file, "unable to resolve path: {s}", .{@errorName(err)});
+                return error.AnalysisFail;
+            };
             errdefer gpa.free(resolved_path);
 
             try man.addFilePostContents(resolved_path, source.bytes, source.stat);
diff --git a/src/main.zig b/src/main.zig
index 2f005b57a4..7df247f1a9 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -2763,7 +2763,14 @@ fn buildOutputType(
             defer gpa.free(rel_src_path);
             break :blk try Package.create(gpa, p, rel_src_path);
         } else {
-            break :blk try Package.create(gpa, fs.path.dirname(src_path), fs.path.basename(src_path));
+            const root_src_dir_path = fs.path.dirname(src_path);
+            break :blk Package.create(gpa, root_src_dir_path, fs.path.basename(src_path)) catch |err| {
+                if (root_src_dir_path) |p| {
+                    fatal("unable to open '{s}': {s}", .{ p, @errorName(err) });
+                } else {
+                    return err;
+                }
+            };
         }
     } else null;
     defer if (main_pkg) |p| p.destroy(gpa);
@@ -2792,7 +2799,7 @@ fn buildOutputType(
     var zig_lib_directory: Compilation.Directory = if (override_lib_dir) |lib_dir| .{
         .path = lib_dir,
         .handle = fs.cwd().openDir(lib_dir, .{}) catch |err| {
-            fatal("unable to open zig lib directory from 'zig-lib-dir' argument or env, '{s}': {s}", .{ lib_dir, @errorName(err) });
+            fatal("unable to open zig lib directory '{s}': {s}", .{ lib_dir, @errorName(err) });
         },
     } else introspect.findZigLibDirFromSelfExe(arena, self_exe_path) catch |err| {
         fatal("unable to find zig installation directory: {s}\n", .{@errorName(err)});