diff --git a/src/core/html.ml b/src/core/html.ml
index 6e615d0a7..0493a4b3a 100644
--- a/src/core/html.ml
+++ b/src/core/html.ml
@@ -62,7 +62,8 @@ let generatePage orig =
   let orig = Filename.basename orig in
   (* Merge different code blocks into, as long as there isn't anything inbetween *)
   let fixCodeRegex = Str.regexp "</code></pre>\\(\\([\r\n\t]\\|<br>\\)*?\\)<pre><code>" in
-  let page = Str.global_replace fixCodeRegex "\\1" (Buffer.contents page) in
+  let page = Buffer.contents page in
+  let page = Str.global_replace fixCodeRegex "\\1" page in
   let page = Str.global_replace (Str.regexp_string "|-") "&#8866;" page in
   let page = Str.global_replace (Str.regexp_string "..") "&hellip;" page in
   let page = Str.global_replace (Str.regexp_string "->") "&#x2192" page in
diff --git a/src/core/interactive.ml b/src/core/interactive.ml
index d03c171a2..2051db865 100644
--- a/src/core/interactive.ml
+++ b/src/core/interactive.ml
@@ -420,7 +420,7 @@ let whale_str =
 
 let whale =
   let open Format in
-  let emit = fprintf str_formatter "%s" in
+  let emit = pp_print_string str_formatter in
   let pass c = emit (String.make 1 c) in
   let full_block = "\xe2\x96\x88" in
   let light_shade = "\xe2\x96\x91" in
diff --git a/src/core/prettyext.ml b/src/core/prettyext.ml
index bb582fbc0..daaa82c0f 100644
--- a/src/core/prettyext.ml
+++ b/src/core/prettyext.ml
@@ -284,7 +284,7 @@ module Make (_ : Store.Cid.RENDERER) : Printer.Ext.T = struct
         match start with
         | LF.EmptySub _ -> pp_empty ppf ()
         | LF.Id _ ->
-           fprintf ppf "%s" (symbol_to_html Dots);
+           pp_print_string ppf (symbol_to_html Dots);
            true
         | LF.SVar (_, s, sub') ->
            print_svar s sub';
@@ -299,10 +299,10 @@ module Make (_ : Store.Cid.RENDERER) : Printer.Ext.T = struct
       then Fmt.comma ppf ();
 
       pp_print_list ~pp_sep: Fmt.comma
-        print_tm ppf tms;
+        print_tm ppf tms
     in
 
-    fprintf ppf "@[<h>%a@]" go ();
+    fprintf ppf "@[<h>%a@]" go ()
 
   and fmt_ppr_lf_typ_rec ppf typrec =
     let ppr_element ppf suffix (x, tA) =
@@ -406,17 +406,15 @@ module Make (_ : Store.Cid.RENDERER) : Printer.Ext.T = struct
          (Id.render_name x)
          (fmt_ppr_lf_typ lvl) tA
     | LF.TypDeclOpt x ->
-       fprintf ppf "%s" (Id.render_name x)
+       pp_print_string ppf (Id.render_name x)
 
   and fmt_ppr_lf_dctx lvl ppf =
     function
     | LF.CtxHole -> fprintf ppf "_"
-    | LF.Null ->
-       fprintf ppf ""
+    | LF.Null -> ()
 
     | LF.CtxVar (_, x) ->
-       fprintf ppf "%s"
-         (Id.render_name x)
+       pp_print_string ppf (Id.render_name x)
 
     | LF.DDec (LF.Null, d) ->
        fmt_ppr_lf_typ_decl lvl ppf d
@@ -536,8 +534,7 @@ module Make (_ : Store.Cid.RENDERER) : Printer.Ext.T = struct
 
   let rec fmt_ppr_meta_spine lvl ppf =
     function
-    | Comp.MetaNil ->
-       fprintf ppf ""
+    | Comp.MetaNil -> ()
     | Comp.MetaApp (mO, mS) ->
        fprintf ppf " %a%a"
          (fmt_ppr_cmp_meta_obj (lvl + 1)) mO