feat: prevent fields with invalid types

conf.v

@@ -51,6 +51,17 @@ fn (ld LoadConfig) get_env_var(field_name string) !(bool, string) {
 // given from an environment variable, a value defined in the config file or a
 // configured default if present, in that order.
 pub fn load<T>(ld LoadConfig) !T {
+	// Ensure all struct fields consist of supported types
+	$for field in T.fields {
+		$if field.typ is string || field.typ is int {
+		} $else {
+			// I'd prefer changing this to $compile_error, but as of V 0.3.2,
+			// this seems to be bugged. If I replace this call with a
+			// $compile_error call, the error *always* happens, even if all
+			// fields are correct.
+			return error('Field $field.name is of an unsupported type.')
+		}
+	}
 	mut res := T{}
 
 	// This array allows us to determine later whether the variable is actually
@@ -73,9 +84,6 @@ pub fn load<T>(ld LoadConfig) !T {
 					res.$(field.name) = s.string()
 				} $else $if field.typ is int {
 					res.$(field.name) = s.int()
-					// This seems to not work in V 0.3.2
-					//} $else {
-					//	$compile_error('Unsupported config struct field type detected.')
 				}
 
 				has_value.add(field.name)
@@ -93,9 +101,6 @@ pub fn load<T>(ld LoadConfig) !T {
 				res.$(field.name) = env_value
 			} $else $if field.typ is int {
 				res.$(field.name) = env_value.int()
-				// This seems to not work in V 0.3.2
-				//} $else {
-				//	$compile_error('Unsupported config struct field type detected.')
 			}
 
 			has_value.add(field.name)

conf_test.v

@@ -0,0 +1,10 @@
+module conf
+
+struct WrongTypeConfig {
+    f  map[string]string
+}
+
+fn test_wrong_type() {
+	conf := load<WrongTypeConfig>() or { return }
+	assert false
+}

int_test.v

@@ -181,3 +181,8 @@ fn test_int_absent_default_empty() {
 		some_int: 0
 	}
 }
+
+/* fn test_int_wrong_type() { */
+/* 	conf := load<SingleConf>(default_path: 'test/int_wrong_type.toml') or { return } */
+/* 	assert false */
+/* } */

test/int_wrong_type.toml

@@ -0,0 +1 @@
+some_int = '1'