diff --git a/vlib/builtin/array_test.v b/vlib/builtin/array_test.v
index 73b0ba69f183c4..56ba06216d8700 100644
--- a/vlib/builtin/array_test.v
+++ b/vlib/builtin/array_test.v
@@ -341,11 +341,11 @@ mut:
 	b []Test2
 }
 
-fn (t Test2) str() string {
+pub fn (t Test2) str() string {
 	return '{$t.one $t.two}'
 }
 
-fn (t Test) str() string {
+pub  fn (t Test) str() string {
 	return '{$t.a $t.b}'
 }
 
diff --git a/vlib/compiler/cflags.v b/vlib/compiler/cflags.v
index cc0dae78c7a315..0df0cdcf178103 100644
--- a/vlib/compiler/cflags.v
+++ b/vlib/compiler/cflags.v
@@ -14,7 +14,7 @@ struct CFlag{
 	value string // eg. /path/to/include
 }
 
-fn (c &CFlag) str() string {
+pub fn (c &CFlag) str() string {
 	return 'CFlag{ name: "$c.name" value: "$c.value" mod: "$c.mod" os: "$c.os" }'
 }
 
diff --git a/vlib/compiler/compile_errors.v b/vlib/compiler/compile_errors.v
index b095a87b2f57e4..a14ac775064d79 100644
--- a/vlib/compiler/compile_errors.v
+++ b/vlib/compiler/compile_errors.v
@@ -199,7 +199,7 @@ mut:
    last_nl_pos int
 }
 
-fn (s ScannerPos) str() string {
+pub fn (s ScannerPos) str() string {
 	return 'ScannerPos{ ${s.pos:5d} , ${s.line_nr:5d} , ${s.last_nl_pos:5d} }'
 }
 
diff --git a/vlib/compiler/comptime.v b/vlib/compiler/comptime.v
index 69ef51d4770e9e..abcc0e0ddc378c 100644
--- a/vlib/compiler/comptime.v
+++ b/vlib/compiler/comptime.v
@@ -314,7 +314,7 @@ fn (p mut Parser) gen_array_str(typ Type) {
 		p.error('cant print ${elm_type}[], unhandled print of ${elm_type}')
 	}
 	p.v.vgen_buf.writeln('
-fn (a $typ.name) str() string {
+pub fn (a $typ.name) str() string {
 	mut sb := strings.new_builder(a.len * 3)
 	sb.write("[")
 	for i, elm in a {
@@ -342,7 +342,7 @@ fn (p mut Parser) gen_struct_str(typ Type) {
 	})
 
 	mut sb := strings.new_builder(typ.fields.len * 20)
-	sb.writeln('fn (a $typ.name) str() string {\nreturn')
+	sb.writeln('pub fn (a $typ.name) str() string {\nreturn')
 	sb.writeln("'{")
 	for field in typ.fields {
 		sb.writeln('\t$field.name: $' + 'a.${field.name}')
@@ -366,7 +366,7 @@ fn (p mut Parser) gen_varg_str(typ Type) {
 		p.gen_struct_str(elm_type2)
 	}
 	p.v.vgen_buf.writeln('
-fn (a $typ.name) str() string {
+pub fn (a $typ.name) str() string {
 	mut sb := strings.new_builder(a.len * 3)
 	sb.write("[")
 	for i, elm in a {
diff --git a/vlib/compiler/fn.v b/vlib/compiler/fn.v
index 6c645deb954e85..e09b5f7d837f12 100644
--- a/vlib/compiler/fn.v
+++ b/vlib/compiler/fn.v
@@ -60,7 +60,7 @@ const (
 	MainFn = Fn{ name: 'main' }
 )
 
-fn (a []TypeInst) str() string {
+pub fn (a []TypeInst) str() string {
 	mut r := []string
 	for t in a {
 		mut s := ' | '
@@ -254,7 +254,7 @@ fn (p mut Parser) fn_decl() {
 		}
 		// Don't allow modifying types from a different module
 		if !p.first_pass() && !p.builtin_mod && t.mod != p.mod &&
-			!p.is_vgen // allow .str()
+			!p.is_vgen // let vgen define methods like .str() on types defined in other modules
 		{
 			//println('T.mod=$T.mod')
 			//println('p.mod=$p.mod')
@@ -297,6 +297,10 @@ fn (p mut Parser) fn_decl() {
 	if f.name == 'init' && !f.is_method && f.is_public && !p.is_vh {
 		p.error('init function cannot be public')
 	}
+	// .str() methods
+	if f.is_method && f.name == 'str' && !f.is_public {
+		p.error('.str() methods must be declared as public')
+	}
 	// C function header def? (fn C.NSMakeRect(int,int,int,int))
 	is_c := f.name == 'C' && p.tok == .dot
 	// Just fn signature? only builtin.v + default build mode
@@ -726,7 +730,7 @@ fn (p mut Parser) fn_call(f mut Fn, method_ph int, receiver_var, receiver_type s
 	if f.is_deprecated {
 		p.warn('$f.name is deprecated')
 	}
-	if !f.is_public &&  !f.is_c && !p.pref.is_test && !f.is_interface && f.mod != p.mod {
+	if !f.is_public && !f.is_c && !p.pref.is_test && !f.is_interface && f.mod != p.mod {
 		if f.name == 'contains' {
 			println('use `value in numbers` instead of `numbers.contains(value)`')
 		}
diff --git a/vlib/compiler/table.v b/vlib/compiler/table.v
index 8552ec54939f90..3c0b8383795498 100644
--- a/vlib/compiler/table.v
+++ b/vlib/compiler/table.v
@@ -122,7 +122,7 @@ struct TypeNode {
 
 /*
 // For debugging types
-fn (t Type) str() string {
+pub fn (t Type) str() string {
 	mut s := 'type "$t.name" {'
 	if t.fields.len > 0 {
 		// s += '\n    $t.fields.len fields:\n'
@@ -185,7 +185,7 @@ const (
 )
 
 // This is used for debugging only
-fn (f Fn) str() string {
+pub fn (f Fn) str() string {
 	t := Table{}
 	str_args := f.str_args(t)
 	return '${f.name}($str_args) $f.typ'
diff --git a/vlib/compiler/tests/fn_expecting_ref_but_returning_struct_test.v b/vlib/compiler/tests/fn_expecting_ref_but_returning_struct_test.v
index 9e8d4727d37c2f..f9764586869435 100644
--- a/vlib/compiler/tests/fn_expecting_ref_but_returning_struct_test.v
+++ b/vlib/compiler/tests/fn_expecting_ref_but_returning_struct_test.v
@@ -1,6 +1,6 @@
 struct Foo {
 }
-fn (f Foo) str() string { return 'Foo{}' }
+pub fn (f Foo) str() string { return 'Foo{}' }
 
 fn process_foo(foo &Foo) {
 	println('>process_foo, called for ${foo} === ${*foo}')
diff --git a/vlib/compiler/token.v b/vlib/compiler/token.v
index ef2f15dc77a2c8..d8bfb4500eeb5f 100644
--- a/vlib/compiler/token.v
+++ b/vlib/compiler/token.v
@@ -257,7 +257,7 @@ fn is_key(key string) bool {
 	return int(key_to_token(key)) > 0
 }
 
-fn (t TokenKind) str() string {
+pub fn (t TokenKind) str() string {
 	return TokenStr[int(t)]
 }
 
@@ -290,7 +290,7 @@ fn (t []TokenKind) contains(val TokenKind) bool {
 	return false
 }
 
-fn (t Token) str() string {
+pub fn (t Token) str() string {
 	if t.tok == .number {
 		return t.lit
 
diff --git a/vlib/glm/glm.v b/vlib/glm/glm.v
index 6bbd46d192386c..dfbe561c0e47e1 100644
--- a/vlib/glm/glm.v
+++ b/vlib/glm/glm.v
@@ -49,15 +49,15 @@ fn mat4(f &f32) Mat4 {
 	return res
 }
 
-fn (v Vec3) str() string {
+pub fn (v Vec3) str() string {
 	return 'Vec3{ $v.x, $v.y, $v.z }'
 }
 
-fn (v Vec2) str() string {
+pub fn (v Vec2) str() string {
 	return 'Vec3{ $v.x, $v.y }'
 }
 
-fn (m Mat4) str() string {
+pub fn (m Mat4) str() string {
 	mut s := '[ '
 	for i := 0; i < 4; i++ {
 		if i != 0 {