checker: error on redefining any of the public builtin functions, not…

… just ['print', 'println', 'eprint', 'eprintln', 'isnil', 'panic', 'exit'] (#13419)

vlib/v/ast/ast.v

@@ -449,8 +449,9 @@ pub mut:
 // function or method declaration
 pub struct FnDecl {
 pub:
-	name            string
-	mod             string
+	name            string // 'math.bits.normalize'
+	short_name      string // 'normalize'
+	mod             string // 'math.bits'
 	is_deprecated   bool
 	is_pub          bool
 	is_variadic     bool

vlib/v/ast/table.v

@@ -41,6 +41,7 @@ pub mut:
 	enum_decls        map[string]EnumDecl
 	mdeprecated_msg   map[string]string    // module deprecation message
 	mdeprecated_after map[string]time.Time // module deprecation date
+	builtin_pub_fns   map[string]bool
 }
 
 // used by vls to avoid leaks
@@ -315,6 +316,9 @@ pub fn (mut t Table) mark_module_as_deprecated_after(mname string, after_date st
 
 pub fn (mut t Table) register_fn(new_fn Fn) {
 	t.fns[new_fn.name] = new_fn
+	if new_fn.is_pub && new_fn.mod == 'builtin' {
+		t.builtin_pub_fns[new_fn.name] = true
+	}
 }
 
 pub fn (mut t Table) register_interface(idecl InterfaceDecl) {

vlib/v/checker/fn.v

@@ -70,6 +70,9 @@ fn (mut c Checker) fn_decl(mut node ast.FnDecl) {
 	}
 	if node.language == .v && !c.is_builtin_mod && !node.is_anon {
 		c.check_valid_snake_case(node.name, 'function name', node.pos)
+		if !node.is_method && node.mod == 'main' && node.short_name in c.table.builtin_pub_fns {
+			c.error('cannot redefine builtin public function `$node.short_name`', node.pos)
+		}
 	}
 	if node.name == 'main.main' {
 		c.main_fn_decl_node = *node

vlib/v/checker/tests/redefining_builtin_pub_functions.out

@@ -0,0 +1,12 @@
+vlib/v/checker/tests/redefining_builtin_pub_functions.vv:1:1: error: cannot redefine builtin public function `exit`
+    1 | fn exit(x string) {
+      | ~~~~~~~~~~~~~~~~~
+    2 |     println('my exit: $x')
+    3 | }
+vlib/v/checker/tests/redefining_builtin_pub_functions.vv:5:1: error: cannot redefine builtin public function `print_backtrace`
+    3 | }
+    4 | 
+    5 | fn print_backtrace() {
+      | ~~~~~~~~~~~~~~~~~~~~
+    6 |     println('hello')
+    7 | }

vlib/v/checker/tests/redefining_builtin_pub_functions.vv

@@ -0,0 +1,11 @@
+fn exit(x string) {
+	println('my exit: $x')
+}
+
+fn print_backtrace() {
+	println('hello')
+}
+
+fn main() {
+	print_backtrace()
+}

vlib/v/gen/js/fn.v

@@ -2,9 +2,10 @@ module js
 
 import v.ast
 import v.util
-import v.parser
 import strings
 
+pub const builtin_functions = ['print', 'println', 'eprint', 'eprintln', 'isnil', 'panic', 'exit']
+
 fn (mut g JsGen) js_mname(name_ string) string {
 	mut is_js := false
 	is_overload := ['+', '-', '*', '/', '==', '<', '>']
@@ -406,7 +407,7 @@ fn (mut g JsGen) gen_call_expr(it ast.CallExpr) {
 	mut name := g.js_name(it.name)
 
 	is_print := name in ['print', 'println', 'eprint', 'eprintln', 'panic']
-	if name in parser.builtin_functions {
+	if name in js.builtin_functions {
 		name = 'builtin__$name'
 	}
 	print_method := name
@@ -623,7 +624,7 @@ fn (mut g JsGen) gen_method_decl(it ast.FnDecl, typ FnGenType) {
 	name = g.js_name(name)
 
 	name = g.generic_fn_name(g.cur_concrete_types, name, true)
-	if name in parser.builtin_functions {
+	if name in js.builtin_functions {
 		name = 'builtin__$name'
 	}
 	if it.is_pub && !it.is_method {
@@ -797,7 +798,7 @@ fn (mut g JsGen) gen_anon_fn(mut fun ast.AnonFn) {
 	name = g.js_name(name)
 
 	name = g.generic_fn_name(g.table.cur_concrete_types, name, true)
-	if name in parser.builtin_functions {
+	if name in js.builtin_functions {
 		name = 'builtin__$name'
 	}
 	if it.is_pub && !it.is_method {

vlib/v/parser/fn.v

@@ -281,12 +281,6 @@ fn (mut p Parser) fn_decl() ast.FnDecl {
 			}
 		}
 		if !p.pref.is_fmt {
-			if !is_method && !p.builtin_mod && name in builtin_functions {
-				p.error_with_pos('cannot redefine builtin function `$name`', name_pos)
-				return ast.FnDecl{
-					scope: 0
-				}
-			}
 			if name in p.imported_symbols {
 				p.error_with_pos('cannot redefine imported function `$name`', name_pos)
 				return ast.FnDecl{
@@ -493,6 +487,7 @@ fn (mut p Parser) fn_decl() ast.FnDecl {
 	// }
 	fn_decl := ast.FnDecl{
 		name: name
+		short_name: short_fn_name
 		mod: p.mod
 		stmts: stmts
 		return_type: return_type
@@ -704,6 +699,7 @@ fn (mut p Parser) anon_fn() ast.AnonFn {
 	return ast.AnonFn{
 		decl: ast.FnDecl{
 			name: name
+			short_name: ''
 			mod: p.mod
 			stmts: stmts
 			return_type: return_type
@@ -1011,7 +1007,7 @@ fn (mut p Parser) check_fn_atomic_arguments(typ ast.Type, pos token.Pos) {
 fn have_fn_main(stmts []ast.Stmt) bool {
 	for stmt in stmts {
 		if stmt is ast.FnDecl {
-			if stmt.name == 'main.main' && stmt.mod == 'main' {
+			if stmt.name == 'main.main' {
 				return true
 			}
 		}

vlib/v/parser/parser.v

@@ -14,8 +14,6 @@ import v.errors
 import os
 import hash.fnv1a
 
-pub const builtin_functions = ['print', 'println', 'eprint', 'eprintln', 'isnil', 'panic', 'exit']
-
 pub struct Parser {
 	pref &pref.Preferences
 mut:
@@ -654,6 +652,7 @@ pub fn (mut p Parser) top_stmt() ast.Stmt {
 					p.close_scope()
 					return ast.FnDecl{
 						name: 'main.main'
+						short_name: 'main'
 						mod: 'main'
 						is_main: true
 						stmts: stmts

vlib/v/parser/struct.v

@@ -584,6 +584,7 @@ fn (mut p Parser) interface_decl() ast.InterfaceDecl {
 			args << args2
 			mut method := ast.FnDecl{
 				name: name
+				short_name: name
 				mod: p.mod
 				params: args
 				file: p.file_name

vlib/v/parser/tests/fn_use_builtin_err.out

@@ -1,5 +1,5 @@
-vlib/v/parser/tests/fn_use_builtin_err.vv:1:4: error: cannot redefine builtin function `print`
+vlib/v/parser/tests/fn_use_builtin_err.vv:1:1: error: cannot redefine builtin public function `print`
     1 | fn print(strings ...string) {
-      |    ~~~~~
+      | ~~~~~~~~~~~~~~~~~~~~~~~~~~~
     2 |     for s in strings {
     3 |         println(s)