checker: string != IError (#10665)

vlib/os/os_windows.c.v

@@ -485,7 +485,7 @@ pub fn hostname() string {
 	size := u32(255)
 	res := C.GetComputerNameW(&hostname[0], &size)
 	if !res {
-		return error(get_error_msg(int(C.GetLastError())))
+		return get_error_msg(int(C.GetLastError()))
 	}
 	return unsafe { string_from_wide(&hostname[0]) }
 }
@@ -495,7 +495,7 @@ pub fn loginname() string {
 	size := u32(255)
 	res := C.GetUserNameW(&loginname[0], &size)
 	if !res {
-		return error(get_error_msg(int(C.GetLastError())))
+		return get_error_msg(int(C.GetLastError()))
 	}
 	return unsafe { string_from_wide(&loginname[0]) }
 }

vlib/v/checker/check_types.v

@@ -130,10 +130,6 @@ pub fn (mut c Checker) check_basic(got ast.Type, expected ast.Type) bool {
 	if got_sym.kind == .function && exp_sym.kind == .function {
 		return c.check_matching_function_symbols(got_sym, exp_sym)
 	}
-	// allow using Error as a string for now (avoid a breaking change)
-	if got == ast.error_type_idx && expected == ast.string_type_idx {
-		return true
-	}
 	// allow `return 0` in a function with `?int` return type
 	expected_nonflagged := expected.clear_flags()
 	if got == ast.int_literal_type && expected_nonflagged.is_int() {

vlib/v/checker/tests/store_string_err.out

@@ -0,0 +1,6 @@
+vlib/v/checker/tests/store_string_err.vv:5:26: error: wrong return type `IError` in the `or {}` block, expected `int`
+    3 | }
+    4 | 
+    5 | err := return_err() or { err }
+      |                          ~~~
+    6 | eprintln(err)

vlib/v/checker/tests/store_string_err.vv

@@ -0,0 +1,6 @@
+fn return_err() ?int {
+	return error('')
+}
+
+err := return_err() or { err }
+eprintln(err)

vlib/v/pkgconfig/pkgconfig_test.v

@@ -21,7 +21,7 @@ fn test_dependency_resolution_fails_correctly() {
 	mut errors := []string{}
 	for pc in pc_files {
 		pcname := os.file_name(pc).replace('.pc', '')
-		pkgconfig.load(pcname, use_default_paths: false, path: samples_dir) or { errors << err }
+		pkgconfig.load(pcname, use_default_paths: false, path: samples_dir) or { errors << err.msg }
 	}
 	assert errors.len < pc_files.len
 	assert errors == ['could not resolve dependency xyz-unknown-package']

vlib/v/scanner/scanner.v

@@ -106,7 +106,7 @@ pub fn new_scanner_file(file_path string, comments_mode CommentsMode, pref &pref
 		verror("$file_path doesn't exist")
 	}
 	raw_text := util.read_file(file_path) or {
-		verror(err)
+		verror(err.msg)
 		return voidptr(0)
 	}
 	mut s := &Scanner{

vlib/v/tests/repl/runner/runner.v

@@ -35,7 +35,7 @@ pub fn full_path_to_v(dirs_in int) string {
 }
 
 fn diff_files(file_result string, file_expected string) string {
-	diffcmd := diff.find_working_diff_command() or { return err }
+	diffcmd := diff.find_working_diff_command() or { return err.msg }
 	return diff.color_compare_files(diffcmd, file_result, file_expected)
 }