diff --git a/src/Nixfmt/Pretty.hs b/src/Nixfmt/Pretty.hs
index c9601a5c..70fce906 100644
--- a/src/Nixfmt/Pretty.hs
+++ b/src/Nixfmt/Pretty.hs
@@ -656,9 +656,26 @@ instance Pretty StringPart where
 
 instance Pretty [StringPart] where
     -- When the interpolation is the only thing on the string line,
-    -- then absorb the content (i.e. don't surround with line')
+    -- then absorb the content (i.e. don't surround with line').
+    -- Only do this when there are no comments
+    pretty [Interpolation (Whole expr [])]
+        = group $ text "${" <> nest inner <> text "}"
+        where
+            -- Code copied over from parentheses. Could be factored out into a common function one day
+            inner = case expr of
+                -- Start on the same line for these
+                _ | isAbsorbableExpr expr -> group $ absorbExpr False expr
+                -- Parenthesized application
+                (Application f a) -> prettyApp True mempty True f a
+                -- Same thing for selections
+                (Term (Selection t _)) | isAbsorbable t -> line' <> group expr <> line'
+                (Term (Selection _ _)) -> group expr <> line'
+                -- Start on a new line for the others
+                _ -> line' <> group expr <> line'
+
+    -- Fallback case: there are some comments around it. Always surround with line' then
     pretty [Interpolation expr]
-        = group $ text "${" <> pretty expr <> text "}"
+        = group $ text "${" <> surroundWith line' (nest expr) <> text "}"
 
     -- If we split a string line over multiple code lines due to large
     -- interpolations, make sure to indent based on the indentation of the line
diff --git a/test/diff/string_interpol/in.nix b/test/diff/string_interpol/in.nix
index a861ff8e..01c0d0dd 100644
--- a/test/diff/string_interpol/in.nix
+++ b/test/diff/string_interpol/in.nix
@@ -1,5 +1,6 @@
 [
   "${/*a*/"${/*b*/"${c}"}"/*d*/}"
+  ''${/*a*/''${/*b*/''${c}''}''/*d*/}''
   {
     ExecStart = "${pkgs.openarena}/bin/oa_ded +set fs_basepath ${pkgs.openarena}/openarena-0.8.8 +set fs_homepath /var/lib/openarena ${
         concatMapStringsSep (x: x) " " cfg.extraFlags
@@ -26,4 +27,56 @@
         }
     '';
   }
+  {
+    system.nixos.versionSuffix1 = ".${
+      final.substring 0 8 (
+        self.lastModifiedDate or self.lastModified
+          or "19700101"
+        self.lastModifiedDate or self.lastModified or "19700101"
+      )
+    }.${self.shortRev or "dirty"}";
+
+    system.nixos.versionSuffix2 = ".${
+      final.substring 0 8 (
+        self.lastModifiedDate or self.lastModified
+          or "19700101"
+        self.lastModifiedDate or self.lastModified or "19700101"
+      )
+    }";
+
+    system.nixos.versionSuffix3 = "${
+      final.substring 0 8 (
+        self.lastModifiedDate or self.lastModified
+          or "19700101"
+        self.lastModifiedDate or self.lastModified or "19700101"
+      )
+    }";
+  }
+  (
+    system nixos versionSuffix1 ".${
+      final.substring 0 8 (
+        self.lastModifiedDate or self.lastModified
+          or "19700101"
+        self.lastModifiedDate or self.lastModified or "19700101"
+      )
+    }.${self.shortRev or "dirty"}"
+  )
+  (
+    system nixos versionSuffix2 ".${
+      final.substring 0 8 (
+        self.lastModifiedDate or self.lastModified
+          or "19700101"
+        self.lastModifiedDate or self.lastModified or "19700101"
+      )
+    }"
+  )
+  (
+    system nixos versionSuffix3 "${
+      final.substring 0 8 (
+        self.lastModifiedDate or self.lastModified
+          or "19700101"
+        self.lastModifiedDate or self.lastModified or "19700101"
+      )
+    }"
+  )
 ]
diff --git a/test/diff/string_interpol/out.nix b/test/diff/string_interpol/out.nix
index ed65b6bf..643949e4 100644
--- a/test/diff/string_interpol/out.nix
+++ b/test/diff/string_interpol/out.nix
@@ -1,10 +1,18 @@
 [
   "${
-  # a
-  "${
-  # b
-  "${c}"}" # d
+    # a
+    "${
+      # b
+      "${c}"
+    }" # d
   }"
+  ''${
+    # a
+    ''${
+      # b
+      ''${c}''
+    }'' # d
+  }''
   {
     ExecStart = "${pkgs.openarena}/bin/oa_ded +set fs_basepath ${pkgs.openarena}/openarena-0.8.8 +set fs_homepath /var/lib/openarena ${
       concatMapStringsSep (x: x) " " cfg.extraFlags
@@ -42,4 +50,46 @@
         }
     '';
   }
+  {
+    system.nixos.versionSuffix1 = ".${
+      final.substring 0 8 (
+        self.lastModifiedDate or self.lastModified or "19700101"
+          self.lastModifiedDate or self.lastModified or "19700101"
+      )
+    }.${self.shortRev or "dirty"}";
+
+    system.nixos.versionSuffix2 = ".${
+      final.substring 0 8 (
+        self.lastModifiedDate or self.lastModified or "19700101"
+          self.lastModifiedDate or self.lastModified or "19700101"
+      )
+    }";
+
+    system.nixos.versionSuffix3 = "${final.substring 0 8 (
+      self.lastModifiedDate or self.lastModified or "19700101"
+        self.lastModifiedDate or self.lastModified or "19700101"
+    )}";
+  }
+  (system nixos versionSuffix1
+    ".${
+      final.substring 0 8 (
+        self.lastModifiedDate or self.lastModified or "19700101"
+          self.lastModifiedDate or self.lastModified or "19700101"
+      )
+    }.${self.shortRev or "dirty"}"
+  )
+  (system nixos versionSuffix2
+    ".${
+      final.substring 0 8 (
+        self.lastModifiedDate or self.lastModified or "19700101"
+          self.lastModifiedDate or self.lastModified or "19700101"
+      )
+    }"
+  )
+  (system nixos versionSuffix3
+    "${final.substring 0 8 (
+      self.lastModifiedDate or self.lastModified or "19700101"
+        self.lastModifiedDate or self.lastModified or "19700101"
+    )}"
+  )
 ]