diff --git a/src/runtime/c/pgf/pgf.h b/src/runtime/c/pgf/pgf.h
index 5d01a1ff6..06776570c 100644
--- a/src/runtime/c/pgf/pgf.h
+++ b/src/runtime/c/pgf/pgf.h
@@ -207,9 +207,9 @@ struct PgfUnmarshallerVtbl {
     PgfLiteral (*lflt)(PgfUnmarshaller *this, double v);
     PgfLiteral (*lstr)(PgfUnmarshaller *this, PgfText *v);
     PgfType (*dtyp)(PgfUnmarshaller *this,
-                    int n_hypos, PgfTypeHypo *hypos,
+                    size_t n_hypos, PgfTypeHypo *hypos,
                     PgfText *cat,
-                    int n_exprs, PgfExpr *exprs);
+                    size_t n_exprs, PgfExpr *exprs);
     void (*free_ref)(PgfUnmarshaller *this, object x);
 };
 struct PgfUnmarshaller {
diff --git a/src/runtime/c/pgf/printer.cxx b/src/runtime/c/pgf/printer.cxx
index eb35acfb3..ab947e18f 100644
--- a/src/runtime/c/pgf/printer.cxx
+++ b/src/runtime/c/pgf/printer.cxx
@@ -417,14 +417,14 @@ PgfType PgfPrinter::dtyp(size_t n_hypos, PgfTypeHypo *hypos,
 
     PgfPrintContext *save_ctxt = ctxt;
 
-    for (int i = 0; i < n_hypos; i++) {
+    for (size_t i = 0; i < n_hypos; i++) {
         hypo(&hypos[i],1);
         puts(" -> ");
     }
 
     efun(cat);
 
-    for (int i = 0; i < n_exprs; i++) {
+    for (size_t i = 0; i < n_exprs; i++) {
         puts(" ");
         prio = 4;
         m->match_expr(this, exprs[i]);