diff --git a/vlib/v/gen/auto_str_methods.v b/vlib/v/gen/auto_str_methods.v
index c46ce4bc34..f23d227edf 100644
--- a/vlib/v/gen/auto_str_methods.v
+++ b/vlib/v/gen/auto_str_methods.v
@@ -160,25 +160,29 @@ fn (mut g Gen) gen_str_for_array(info table.Array, styp string, str_fn_name stri
 	g.auto_str_funcs.writeln('\tstrings__Builder sb = strings__new_builder(a.len * 10);')
 	g.auto_str_funcs.writeln('\tstrings__Builder_write(&sb, _SLIT("["));')
 	g.auto_str_funcs.writeln('\tfor (int i = 0; i < a.len; ++i) {')
-	g.auto_str_funcs.writeln('\t\t$field_styp it = (*($field_styp*)array_get(a, i));')
-	if sym.kind == .struct_ && !sym_has_str_method {
-		if is_elem_ptr {
-			g.auto_str_funcs.writeln('\t\tstring x = indent_${elem_str_fn_name}(*it, indent_count);')
-		} else {
-			g.auto_str_funcs.writeln('\t\tstring x = indent_${elem_str_fn_name}(it, indent_count);')
-		}
-	} else if sym.kind in [.f32, .f64] {
-		g.auto_str_funcs.writeln('\t\tstring x = _STR("%g", 1, it);')
+	if sym.kind == .function {
+		g.auto_str_funcs.writeln('\t\tstring x = ${elem_str_fn_name}();')
 	} else {
-		// There is a custom .str() method, so use it.
-		// NB: we need to take account of whether the user has defined
-		// `fn (x T) str() {` or `fn (x &T) str() {`, and convert accordingly
-		if (str_method_expects_ptr && is_elem_ptr) || (!str_method_expects_ptr && !is_elem_ptr) {
-			g.auto_str_funcs.writeln('\t\tstring x = ${elem_str_fn_name}(it);')
-		} else if str_method_expects_ptr && !is_elem_ptr {
-			g.auto_str_funcs.writeln('\t\tstring x = ${elem_str_fn_name}(&it);')
-		} else if !str_method_expects_ptr && is_elem_ptr {
-			g.auto_str_funcs.writeln('\t\tstring x = ${elem_str_fn_name}(*it);')
+		g.auto_str_funcs.writeln('\t\t$field_styp it = (*($field_styp*)array_get(a, i));')
+		if sym.kind == .struct_ && !sym_has_str_method {
+			if is_elem_ptr {
+				g.auto_str_funcs.writeln('\t\tstring x = indent_${elem_str_fn_name}(*it, indent_count);')
+			} else {
+				g.auto_str_funcs.writeln('\t\tstring x = indent_${elem_str_fn_name}(it, indent_count);')
+			}
+		} else if sym.kind in [.f32, .f64] {
+			g.auto_str_funcs.writeln('\t\tstring x = _STR("%g", 1, it);')
+		} else {
+			// There is a custom .str() method, so use it.
+			// NB: we need to take account of whether the user has defined
+			// `fn (x T) str() {` or `fn (x &T) str() {`, and convert accordingly
+			if (str_method_expects_ptr && is_elem_ptr) || (!str_method_expects_ptr && !is_elem_ptr) {
+				g.auto_str_funcs.writeln('\t\tstring x = ${elem_str_fn_name}(it);')
+			} else if str_method_expects_ptr && !is_elem_ptr {
+				g.auto_str_funcs.writeln('\t\tstring x = ${elem_str_fn_name}(&it);')
+			} else if !str_method_expects_ptr && is_elem_ptr {
+				g.auto_str_funcs.writeln('\t\tstring x = ${elem_str_fn_name}(*it);')
+			}
 		}
 	}
 	g.auto_str_funcs.writeln('\t\tstrings__Builder_write(&sb, x);')
@@ -224,20 +228,24 @@ fn (mut g Gen) gen_str_for_array_fixed(info table.ArrayFixed, styp string, str_f
 	g.auto_str_funcs.writeln('static string indent_${str_fn_name}($styp a, int indent_count) {')
 	g.auto_str_funcs.writeln('\tstrings__Builder sb = strings__new_builder($info.size * 10);')
 	g.auto_str_funcs.writeln('\tstrings__Builder_write(&sb, _SLIT("["));')
-	g.auto_str_funcs.writeln('\tfor (int i = 0; i < $info.size; ++i) {')
-	if sym.kind == .struct_ && !sym_has_str_method {
-		g.auto_str_funcs.writeln('\t\tstrings__Builder_write(&sb, ${elem_str_fn_name}(a[i], indent_count));')
-	} else if sym.kind in [.f32, .f64] {
-		g.auto_str_funcs.writeln('\t\tstrings__Builder_write(&sb, _STR("%g", 1, a[i]));')
-	} else if sym.kind == .string {
-		g.auto_str_funcs.writeln('\t\tstrings__Builder_write(&sb, _STR("\'%.*s\\000\'", 2, a[i]));')
+	if sym.kind == .function {
+		g.auto_str_funcs.writeln('\t\tstring x = ${elem_str_fn_name}();')
 	} else {
-		if (str_method_expects_ptr && is_elem_ptr) || (!str_method_expects_ptr && !is_elem_ptr) {
-			g.auto_str_funcs.writeln('\t\tstrings__Builder_write(&sb, ${elem_str_fn_name}(a[i]));')
-		} else if str_method_expects_ptr && !is_elem_ptr {
-			g.auto_str_funcs.writeln('\t\tstrings__Builder_write(&sb, ${elem_str_fn_name}(&a[i]));')
-		} else if !str_method_expects_ptr && is_elem_ptr {
-			g.auto_str_funcs.writeln('\t\tstrings__Builder_write(&sb, ${elem_str_fn_name}(*a[i]));')
+		g.auto_str_funcs.writeln('\tfor (int i = 0; i < $info.size; ++i) {')
+		if sym.kind == .struct_ && !sym_has_str_method {
+			g.auto_str_funcs.writeln('\t\tstrings__Builder_write(&sb, ${elem_str_fn_name}(a[i], indent_count));')
+		} else if sym.kind in [.f32, .f64] {
+			g.auto_str_funcs.writeln('\t\tstrings__Builder_write(&sb, _STR("%g", 1, a[i]));')
+		} else if sym.kind == .string {
+			g.auto_str_funcs.writeln('\t\tstrings__Builder_write(&sb, _STR("\'%.*s\\000\'", 2, a[i]));')
+		} else {
+			if (str_method_expects_ptr && is_elem_ptr) || (!str_method_expects_ptr && !is_elem_ptr) {
+				g.auto_str_funcs.writeln('\t\tstrings__Builder_write(&sb, ${elem_str_fn_name}(a[i]));')
+			} else if str_method_expects_ptr && !is_elem_ptr {
+				g.auto_str_funcs.writeln('\t\tstrings__Builder_write(&sb, ${elem_str_fn_name}(&a[i]));')
+			} else if !str_method_expects_ptr && is_elem_ptr {
+				g.auto_str_funcs.writeln('\t\tstrings__Builder_write(&sb, ${elem_str_fn_name}(*a[i]));')
+			}
 		}
 	}
 	g.auto_str_funcs.writeln('\t\tif (i < ${info.size - 1}) {')
@@ -271,15 +279,19 @@ fn (mut g Gen) gen_str_for_map(info table.Map, styp string, str_fn_name string)
 	g.auto_str_funcs.writeln('\t\tstring key = *(string*)DenseArray_key(&m.key_values, i);')
 	g.auto_str_funcs.writeln('\t\tstrings__Builder_write(&sb, _STR("\'%.*s\\000\'", 2, key));')
 	g.auto_str_funcs.writeln('\t\tstrings__Builder_write(&sb, _SLIT(": "));')
-	g.auto_str_funcs.writeln('\t\t$val_styp it = *($val_styp*)DenseArray_value(&m.key_values, i);')
-	if val_sym.kind == .string {
-		g.auto_str_funcs.writeln('\t\tstrings__Builder_write(&sb, _STR("\'%.*s\\000\'", 2, it));')
-	} else if val_sym.kind == .struct_ && !val_sym.has_method('str') {
-		g.auto_str_funcs.writeln('\t\tstrings__Builder_write(&sb, indent_${elem_str_fn_name}(it, indent_count));')
-	} else if val_sym.kind in [.f32, .f64] {
-		g.auto_str_funcs.writeln('\t\tstrings__Builder_write(&sb, _STR("%g", 1, it));')
+	if val_sym.kind == .function {
+		g.auto_str_funcs.writeln('\t\tstrings__Builder_write(&sb, ${elem_str_fn_name}());')
 	} else {
-		g.auto_str_funcs.writeln('\t\tstrings__Builder_write(&sb, ${elem_str_fn_name}(it));')
+		g.auto_str_funcs.writeln('\t\t$val_styp it = *($val_styp*)DenseArray_value(&m.key_values, i);')
+		if val_sym.kind == .string {
+			g.auto_str_funcs.writeln('\t\tstrings__Builder_write(&sb, _STR("\'%.*s\\000\'", 2, it));')
+		} else if val_sym.kind == .struct_ && !val_sym.has_method('str') {
+			g.auto_str_funcs.writeln('\t\tstrings__Builder_write(&sb, indent_${elem_str_fn_name}(it, indent_count));')
+		} else if val_sym.kind in [.f32, .f64] {
+			g.auto_str_funcs.writeln('\t\tstrings__Builder_write(&sb, _STR("%g", 1, it));')
+		} else {
+			g.auto_str_funcs.writeln('\t\tstrings__Builder_write(&sb, ${elem_str_fn_name}(it));')
+		}
 	}
 	g.auto_str_funcs.writeln('\t\tif (i != m.key_values.len-1) {')
 	g.auto_str_funcs.writeln('\t\t\tstrings__Builder_write(&sb, _SLIT(", "));')
@@ -335,6 +347,8 @@ fn (mut g Gen) gen_str_for_multi_return(info table.MultiReturn, styp string, str
 			g.auto_str_funcs.writeln('\tstrings__Builder_write(&sb, _STR("%g", 1, a.arg$i));')
 		} else if sym.kind == .string {
 			g.auto_str_funcs.writeln('\tstrings__Builder_write(&sb, _STR("\'%.*s\\000\'", 2, a.arg$i));')
+		} else if sym.kind == .function {
+			g.auto_str_funcs.writeln('\tstrings__Builder_write(&sb, ${str_fn_name}());')
 		} else {
 			if (str_method_expects_ptr && is_arg_ptr) || (!str_method_expects_ptr && !is_arg_ptr) {
 				g.auto_str_funcs.writeln('\tstrings__Builder_write(&sb, ${arg_str_fn_name}(a.arg$i));')
@@ -447,6 +461,8 @@ fn struct_auto_str_func(sym table.TypeSymbol, field_type table.Type, fn_name str
 			return '${fn_name}(it.${c_name(field_name)})'
 		}
 		return 'indent_${fn_name}(it.${c_name(field_name)}, indent_count + 1)'
+	} else if sym.kind == .function {
+		return '${fn_name}()'
 	} else {
 		mut method_str := 'it.${c_name(field_name)}'
 		if sym.kind == .bool {
diff --git a/vlib/v/gen/cgen.v b/vlib/v/gen/cgen.v
index acd5add5eb..512ce84942 100644
--- a/vlib/v/gen/cgen.v
+++ b/vlib/v/gen/cgen.v
@@ -5659,7 +5659,8 @@ fn (g &Gen) type_to_fmt(typ table.Type) string {
 	sym := g.table.get_type_symbol(typ)
 	if typ.is_ptr() && (typ.is_int() || typ.is_float()) {
 		return '%.*s\\000'
-	} else if sym.kind in [.struct_, .array, .array_fixed, .map, .bool, .enum_, .sum_type] {
+	} else if sym.kind in
+		[.struct_, .array, .array_fixed, .map, .bool, .enum_, .sum_type, .function] {
 		return '%.*s\\000'
 	} else if sym.kind == .string {
 		return "\'%.*s\\000\'"
diff --git a/vlib/v/gen/str.v b/vlib/v/gen/str.v
index 513d078022..80b882aeff 100644
--- a/vlib/v/gen/str.v
+++ b/vlib/v/gen/str.v
@@ -177,7 +177,10 @@ fn (mut g Gen) string_inter_literal_sb_optimized(call_expr ast.CallExpr) {
 		typ := node.expr_types[i]
 		g.write(g.typ(typ))
 		g.write('_str(')
-		g.expr(node.exprs[i])
+		sym := g.table.get_type_symbol(typ)
+		if sym.kind != .function {
+			g.expr(node.exprs[i])
+		}
 		g.writeln('));')
 	}
 	g.writeln('')
@@ -366,7 +369,9 @@ fn (mut g Gen) gen_expr_to_string(expr ast.Expr, etype table.Type) {
 	} else {
 		str_fn_name := g.gen_str_for_type(typ)
 		g.write('${str_fn_name}(')
-		g.expr(expr)
+		if sym.kind != .function {
+			g.expr(expr)
+		}
 		g.write(')')
 	}
 }
diff --git a/vlib/v/tests/string_interpolation_function_test.v b/vlib/v/tests/string_interpolation_function_test.v
index b563fdd60e..c21fadd3bf 100644
--- a/vlib/v/tests/string_interpolation_function_test.v
+++ b/vlib/v/tests/string_interpolation_function_test.v
@@ -10,3 +10,30 @@ fn test_function_interpolation() {
 	println(show)
 	assert '$show' == 'fn (string) string'
 }
+
+struct Info {
+	aa fn()string
+	bb int
+}
+
+fn test_function_interpolation_in_struct() {
+	a := Info{
+		aa: fn()string {return 'aaa'}
+		bb: 22
+	}
+	println(a)
+	assert '$a'.contains(': fn () string')
+}
+
+fn test_function_interpolation_in_array() {
+	f := [fn()string{return 'aaa'}, fn()string{return 'bbb'}]
+	println(f)
+	assert '$f' == '[fn () string, fn () string]'
+}
+
+fn test_function_interpolation_in_map() {
+	m := {'aaa': fn()string{return 'aaa'}, 'bbb': fn()string{return 'bbb'}}
+	println(m)
+	assert '$m'.contains(': fn () string')
+}
+