diff --git a/std/special/start.zig b/std/special/start.zig index 76dfe420c4..30298669e3 100644 --- a/std/special/start.zig +++ b/std/special/start.zig @@ -125,10 +125,13 @@ extern fn main(c_argc: i32, c_argv: [*][*]u8, c_envp: [*]?[*]u8) i32 { return callMainWithArgs(@intCast(usize, c_argc), c_argv, envp); } +// General error message for a malformed return type +const bad_main_ret = "expected return type of main to be 'void', '!void', 'noreturn', 'u8', or '!u8'"; + // This is marked inline because for some reason LLVM in release mode fails to inline it, // and we want fewer call frames in stack traces. inline fn callMain() u8 { - switch (@typeId(@typeOf(root.main).ReturnType)) { + switch (@typeInfo(@typeOf(root.main).ReturnType)) { .NoReturn => { root.main(); }, @@ -136,25 +139,32 @@ inline fn callMain() u8 { root.main(); return 0; }, - .Int => { - if (@typeOf(root.main).ReturnType.bit_count != 8) { - @compileError("expected return type of main to be 'u8', 'noreturn', 'void', or '!void'"); + .Int => |info| { + if (info.bits != 8) { + @compileError(bad_main_ret); } return root.main(); }, .ErrorUnion => { - root.main() catch |err| { + const result = root.main() catch |err| { std.debug.warn("error: {}\n", @errorName(err)); - if (builtin.os != builtin.Os.zen) { - if (@errorReturnTrace()) |trace| { - std.debug.dumpStackTrace(trace.*); - } + if (@errorReturnTrace()) |trace| { + std.debug.dumpStackTrace(trace.*); } return 1; }; - return 0; + switch (@typeInfo(@typeOf(result))) { + .Void => return 0, + .Int => |info| { + if (info.bits != 8) { + @compileError(bad_main_ret); + } + return result; + }, + else => @compileError(bad_main_ret), + } }, - else => @compileError("expected return type of main to be 'u8', 'noreturn', 'void', or '!void'"), + else => @compileError(bad_main_ret), } } diff --git a/test/build_examples.zig b/test/build_examples.zig index d38336939d..4733a25b64 100644 --- a/test/build_examples.zig +++ b/test/build_examples.zig @@ -7,6 +7,8 @@ pub fn addCases(cases: *tests.BuildExamplesContext) void { cases.addC("example/hello_world/hello_libc.zig"); cases.add("example/cat/main.zig"); cases.add("example/guess_number/main.zig"); + cases.add("test/standalone/main_return_error/error_u8.zig"); + cases.add("test/standalone/main_return_error/error_u8_non_zero.zig"); cases.addBuildFile("test/standalone/main_pkg_path/build.zig"); cases.addBuildFile("example/shared_library/build.zig"); cases.addBuildFile("example/mix_o_files/build.zig"); diff --git a/test/compile_errors.zig b/test/compile_errors.zig index 9967770931..fd365235d8 100644 --- a/test/compile_errors.zig +++ b/test/compile_errors.zig @@ -2247,7 +2247,7 @@ pub fn addCases(cases: *tests.CompileErrorContext) void { "wrong return type for main", \\pub fn main() f32 { } , - "error: expected return type of main to be 'u8', 'noreturn', 'void', or '!void'", + "error: expected return type of main to be 'void', '!void', 'noreturn', 'u8', or '!u8'", ); cases.add( @@ -2255,7 +2255,7 @@ pub fn addCases(cases: *tests.CompileErrorContext) void { \\pub fn main() ??void { \\} , - "error: expected return type of main to be 'u8', 'noreturn', 'void', or '!void'", + "error: expected return type of main to be 'void', '!void', 'noreturn', 'u8', or '!u8'", ); cases.add( diff --git a/test/standalone/main_return_error/error_u8.zig b/test/standalone/main_return_error/error_u8.zig new file mode 100644 index 0000000000..4edac26afd --- /dev/null +++ b/test/standalone/main_return_error/error_u8.zig @@ -0,0 +1,7 @@ +const Err = error { + Foo +}; + +pub fn main() !u8 { + return Err.Foo; +} diff --git a/test/standalone/main_return_error/error_u8_non_zero.zig b/test/standalone/main_return_error/error_u8_non_zero.zig new file mode 100644 index 0000000000..703a19b314 --- /dev/null +++ b/test/standalone/main_return_error/error_u8_non_zero.zig @@ -0,0 +1,8 @@ +const Err = error { Foo }; + +fn foo() u8 { var x = @intCast(u8, 9); return x; } + +pub fn main() !u8 { + if (foo() == 7) return Err.Foo; + return 123; +}