checker: `[noreturn]` part 2 (cleanup) (#10667)

cmd/tools/vast/vast.v

@@ -480,6 +480,7 @@ fn (t Tree) fn_decl(node ast.FnDecl) &Node {
 	obj.add('is_pub', t.bool_node(node.is_pub))
 	obj.add('is_variadic', t.bool_node(node.is_variadic))
 	obj.add('is_anon', t.bool_node(node.is_anon))
+	obj.add('is_noreturn', t.bool_node(node.is_noreturn))
 	obj.add('is_manualfree', t.bool_node(node.is_manualfree))
 	obj.add('is_main', t.bool_node(node.is_main))
 	obj.add('is_test', t.bool_node(node.is_test))
@@ -1393,22 +1394,24 @@ fn (t Tree) ident_fn(node ast.IdentFn) &Node {
 fn (t Tree) call_expr(node ast.CallExpr) &Node {
 	mut obj := new_object()
 	obj.add('ast_type', t.string_node('CallExpr'))
-	obj.add('left', t.expr(node.left))
-	obj.add('is_method', t.bool_node(node.is_method))
 	obj.add('mod', t.string_node(node.mod))
 	obj.add('name', t.string_node(node.name))
 	obj.add('language', t.enum_node(node.language))
+	obj.add('left_type', t.type_node(node.left_type))
+	obj.add('receiver_type', t.type_node(node.receiver_type))
+	obj.add('return_type', t.type_node(node.return_type))
+	obj.add('left', t.expr(node.left))
+	obj.add('is_method', t.bool_node(node.is_method))
+	obj.add('is_keep_alive', t.bool_node(node.is_keep_alive))
+	obj.add('is_noreturn', t.bool_node(node.is_noreturn))
+	obj.add('should_be_skipped', t.bool_node(node.should_be_skipped))
+	obj.add('free_receiver', t.bool_node(node.free_receiver))
 	obj.add('scope', t.number_node(int(node.scope)))
 	obj.add('args', t.array_node_call_arg(node.args))
 	obj.add('expected_arg_types', t.array_node_type(node.expected_arg_types))
 	obj.add('concrete_types', t.array_node_type(node.concrete_types))
 	obj.add('or_block', t.or_expr(node.or_block))
-	obj.add('left_type', t.type_node(node.left_type))
-	obj.add('receiver_type', t.type_node(node.receiver_type))
-	obj.add('return_type', t.type_node(node.return_type))
-	obj.add('should_be_skipped', t.bool_node(node.should_be_skipped))
 	obj.add('concrete_list_pos', t.position(node.concrete_list_pos))
-	obj.add('free_receiver', t.bool_node(node.free_receiver))
 	obj.add('from_embed_type', t.type_node(node.from_embed_type))
 	obj.add('comments', t.array_node_comment(node.comments))
 	obj.add('pos', t.position(node.pos))

cmd/tools/vfmt.v

@@ -332,6 +332,7 @@ fn get_compile_name_of_potential_v_project(file string) string {
 	return pfolder
 }
 
+[noreturn]
 fn verror(s string) {
 	util.verror('vfmt error', s)
 }

vlib/builtin/builtin.c.v

@@ -13,7 +13,6 @@ fn vhalt() {
 [noreturn]
 pub fn exit(code int) {
 	C.exit(code)
-	vhalt()
 }
 
 fn vcommithash() string {

vlib/builtin/cfns.c.v

@@ -16,7 +16,7 @@ fn C.realloc(a &byte, b int) &byte
 
 fn C.free(ptr voidptr)
 
-[trusted]
+[noreturn; trusted]
 fn C.exit(code int)
 
 fn C.qsort(base voidptr, items size_t, item_size size_t, cb qsort_callback_func)

vlib/os/os_test.v

@@ -343,12 +343,12 @@ fn test_realpath_does_not_absolutize_non_existing_relative_paths() {
 	}
 }
 
-fn test_realpath_absolutepath_symlink() {
+fn test_realpath_absolutepath_symlink() ? {
 	file_name := 'tolink_file.txt'
 	symlink_name := 'symlink.txt'
-	mut f := os.create(file_name) or { panic(err) }
+	mut f := os.create(file_name) ?
 	f.close()
-	assert os.symlink(file_name, symlink_name) or { panic(err) }
+	assert os.symlink(file_name, symlink_name) ?
 	rpath := os.real_path(symlink_name)
 	println(rpath)
 	assert os.is_abs_path(rpath)

vlib/v/builder/builder.v

@@ -461,6 +461,7 @@ fn error_with_pos(s string, fpath string, pos token.Position) {
 	exit(1)
 }
 
+[noreturn]
 fn verror(s string) {
 	util.verror('builder error', s)
 }

vlib/v/builder/compile.v

@@ -30,7 +30,6 @@ pub fn compile(command string, pref &pref.Preferences) {
 	os.is_writable_folder(output_folder) or {
 		// An early error here, is better than an unclear C error later:
 		verror(err.msg)
-		exit(1)
 	}
 	// Construct the V object from command line arguments
 	mut b := new_builder(pref)
@@ -217,9 +216,7 @@ pub fn (v Builder) get_builtin_files() []string {
 		}
 	}
 	// Panic. We couldn't find the folder.
-	verror('`builtin/` not included on module lookup path.
-Did you forget to add vlib to the path? (Use @vlib for default vlib)')
-	panic('Unreachable code reached.')
+	verror('`builtin/` not included on module lookup path.\nDid you forget to add vlib to the path? (Use @vlib for default vlib)')
 }
 
 pub fn (v &Builder) get_user_files() []string {
@@ -259,10 +256,7 @@ pub fn (v &Builder) get_user_files() []string {
 	is_test := v.pref.is_test
 	mut is_internal_module_test := false
 	if is_test {
-		tcontent := os.read_file(dir) or {
-			verror('$dir does not exist')
-			exit(0)
-		}
+		tcontent := os.read_file(dir) or { verror('$dir does not exist') }
 		slines := tcontent.trim_space().split_into_lines()
 		for sline in slines {
 			line := sline.trim_space()
@@ -290,7 +284,6 @@ pub fn (v &Builder) get_user_files() []string {
 	does_exist := os.exists(dir)
 	if !does_exist {
 		verror("$dir doesn't exist")
-		exit(1)
 	}
 	is_real_file := does_exist && !os.is_dir(dir)
 	resolved_link := if is_real_file && os.is_link(dir) { os.real_path(dir) } else { dir }

vlib/v/checker/checker.v

@@ -4756,10 +4756,31 @@ fn (mut c Checker) stmts(stmts []ast.Stmt) {
 	if unreachable.line_nr >= 0 {
 		c.error('unreachable code', unreachable)
 	}
+	c.find_unreachable_statements_after_noreturn_calls(stmts)
 	c.scope_returns = false
 	c.expected_type = ast.void_type
 }
 
+pub fn (mut c Checker) find_unreachable_statements_after_noreturn_calls(stmts []ast.Stmt) {
+	mut prev_stmt_was_noreturn_call := false
+	for stmt in stmts {
+		match stmt {
+			ast.ExprStmt {
+				if stmt.expr is ast.CallExpr {
+					if prev_stmt_was_noreturn_call {
+						c.error('unreachable code after a [noreturn] call', stmt.pos)
+						return
+					}
+					prev_stmt_was_noreturn_call = stmt.expr.is_noreturn
+				}
+			}
+			else {
+				prev_stmt_was_noreturn_call = false
+			}
+		}
+	}
+}
+
 pub fn (mut c Checker) unwrap_generic(typ ast.Type) ast.Type {
 	if typ.has_flag(.generic) {
 		if t_typ := c.table.resolve_generic_to_concrete(typ, c.table.cur_fn.generic_names,

vlib/v/checker/tests/noreturn_with_non_empty_loop_at_end.out

@@ -5,3 +5,9 @@ vlib/v/checker/tests/noreturn_with_non_empty_loop_at_end.vv:4:6: error: [noretur
       |         ^
     5 |         break
     6 |     }
+vlib/v/checker/tests/noreturn_with_non_empty_loop_at_end.vv:18:2: error: unreachable code after a [noreturn] call
+   16 |     eprintln('start')
+   17 |     abc()
+   18 |     eprintln('done')
+      |     ~~~~~~~~~~~~~~~~
+   19 | }

vlib/v/checker/tests/noreturn_with_return.out

@@ -11,3 +11,9 @@ vlib/v/checker/tests/noreturn_with_return.vv:6:2: error: [noreturn] functions sh
       |     ~~~~~~
     7 | }
     8 |
+vlib/v/checker/tests/noreturn_with_return.vv:18:2: error: unreachable code after a [noreturn] call
+   16 |     eprintln('start')
+   17 |     abc()
+   18 |     eprintln('done')
+      |     ~~~~~~~~~~~~~~~~
+   19 | }

vlib/v/checker/tests/noreturn_without_loop_or_another_noreturn_at_end.out

@@ -5,3 +5,9 @@ vlib/v/checker/tests/noreturn_without_loop_or_another_noreturn_at_end.vv:3:2: er
       |     ~~~~~~~~~~~~~
     4 | }
     5 |
+vlib/v/checker/tests/noreturn_without_loop_or_another_noreturn_at_end.vv:15:2: error: unreachable code after a [noreturn] call
+   13 |     eprintln('start')
+   14 |     abc()
+   15 |     eprintln('done')
+      |     ~~~~~~~~~~~~~~~~
+   16 | }

vlib/v/gen/c/cheaders.v

@@ -185,6 +185,23 @@ const c_common_macros = '
 	#endif
 #endif
 
+#if !defined(VUNREACHABLE)
+	#if defined(__GNUC__) && !defined(__clang__)
+		#define V_GCC_VERSION  (__GNUC__ * 10000L + __GNUC_MINOR__ * 100L + __GNUC_PATCHLEVEL__)
+		#if (V_GCC_VERSION >= 40500L)
+			#define VUNREACHABLE()  do { __builtin_unreachable(); } while (0)
+		#endif
+	#endif		
+	#if defined(__clang__) && defined(__has_builtin)
+		#if __has_builtin(__builtin_unreachable)
+			#define VUNREACHABLE()  do { __builtin_unreachable(); } while (0)
+		#endif
+	#endif
+	#ifndef VUNREACHABLE
+		#define VUNREACHABLE() do { } while (0)
+	#endif		
+#endif
+
 //likely and unlikely macros
 #if defined(__GNUC__) || defined(__INTEL_COMPILER) || defined(__clang__)
 	#define _likely_(x)  __builtin_expect(x,1)

vlib/v/gen/c/fn.v

@@ -527,6 +527,10 @@ fn (mut g Gen) call_expr(node ast.CallExpr) {
 			g.write('\n $cur_line $tmp_opt')
 		}
 	}
+	if node.is_noreturn {
+		g.writeln(';')
+		g.write('VUNREACHABLE()')
+	}
 }
 
 fn (mut g Gen) method_call(node ast.CallExpr) {

vlib/v/gen/js/js.v

@@ -300,7 +300,7 @@ pub fn (g JsGen) hashes() string {
 	return res
 }
 
-[inline]
+[noreturn]
 fn verror(msg string) {
 	eprintln('jsgen error: $msg')
 	exit(1)

vlib/v/gen/native/amd64.v

@@ -802,10 +802,7 @@ fn (mut g Gen) assign_stmt(node ast.AssignStmt) {
 						match node.left_types[i] {
 							7 { // ast.IndexExpr {
 								ie := node.left[i] as ast.IndexExpr
-								bracket := name.index('[') or {
-									verror('bracket expected')
-									exit(1)
-								}
+								bracket := name.index('[') or { verror('bracket expected') }
 								var_name := name[0..bracket]
 								mut dest := g.get_var_offset(var_name)
 								index := ie.index as ast.IntegerLiteral

vlib/v/parser/parser.v

@@ -3218,6 +3218,7 @@ fn (p &Parser) new_true_expr() ast.Expr {
 	}
 }
 
+[noreturn]
 fn verror(s string) {
 	util.verror('parser error', s)
 }

vlib/v/scanner/scanner.v

@@ -1399,6 +1399,7 @@ fn (mut s Scanner) vet_error(msg string, fix vet.FixKind) {
 	s.vet_errors << ve
 }
 
+[noreturn]
 pub fn verror(s string) {
 	util.verror('scanner error', s)
 }