diff --git a/vlib/v/checker/str.v b/vlib/v/checker/str.v
index b6b82b7985ffc9..f5680eabe5d0d3 100644
--- a/vlib/v/checker/str.v
+++ b/vlib/v/checker/str.v
@@ -85,7 +85,8 @@ fn (mut c Checker) string_inter_lit(mut node ast.StringInterLiteral) ast.Type {
 					c.error('no known default format for type `${c.table.get_type_name(ftyp)}`',
 						node.fmt_poss[i])
 				}
-			} else if c.comptime.is_comptime(expr) && c.comptime.get_type(expr) != ast.void_type {
+			} else if c.comptime.is_comptime(expr)
+				&& c.comptime.get_type_or_default(expr, ast.void_type) != ast.void_type {
 				// still `_` placeholder for comptime variable without specifier
 				node.need_fmts[i] = false
 			} else {
diff --git a/vlib/v/gen/c/str_intp.v b/vlib/v/gen/c/str_intp.v
index 219b1f6e8a1b88..52d9149ac493cd 100644
--- a/vlib/v/gen/c/str_intp.v
+++ b/vlib/v/gen/c/str_intp.v
@@ -241,7 +241,7 @@ fn (mut g Gen) string_inter_literal(node ast.StringInterLiteral) {
 	mut fmts := node_.fmts.clone()
 	for i, mut expr in node_.exprs {
 		if g.comptime.is_comptime(expr) {
-			ctyp := g.comptime.get_type(expr)
+			ctyp := g.comptime.get_type_or_default(expr, node_.expr_types[i])
 			if ctyp != ast.void_type {
 				node_.expr_types[i] = ctyp
 				if node_.fmts[i] == `_` {
diff --git a/vlib/v/tests/generics/generics_method_str_overload_test.v b/vlib/v/tests/generics/generics_method_str_overload_test.v
index 65572b44cb98f4..0251548534b589 100644
--- a/vlib/v/tests/generics/generics_method_str_overload_test.v
+++ b/vlib/v/tests/generics/generics_method_str_overload_test.v
@@ -5,7 +5,7 @@ struct Gen[G] {
 }
 
 fn (g Gen[G]) str() string {
-	return 'Gen<${G.name}>{${g.id}, ${g.data.str()}, ${g.size}}'
+	return 'Gen<${G.name}>{${g.id}, ${g.data}, ${g.size}}'
 }
 
 fn test_generics_method_str_overload() {