v3: skip disabled non-function declarations

Author: medvednikov

vlib/v3/parser/parser.v

@@ -841,21 +841,42 @@ fn (mut p Parser) top_level_stmt() flat.NodeId {
 // here so the declaration itself is parsed next. When the attribute group is a
 // disabled `@[if flag ?]` (skip_next_decl set), functions are emitted as no-op
 // stubs (empty body): the signature must remain so call sites still type-check
-// and link, but the body is elided. Non-function declarations are emitted as-is.
+// and link, but the body is elided. Other disabled declarations are skipped.
 fn (mut p Parser) parse_decl_after_attrs() flat.NodeId {
-	for p.tok == .semicolon {
-		p.next()
-	}
+	p.consume_decl_prefix_after_attrs()
 	if p.skip_next_decl {
 		p.skip_next_decl = false
-		p.disable_fn_body = true
-		res := p.top_level_stmt()
-		p.disable_fn_body = false
-		return res
+		if p.cur_decl_is_fn() {
+			p.disable_fn_body = true
+			res := p.top_level_stmt()
+			p.disable_fn_body = false
+			p.skip_next_decl = false
+			return res
+		}
+		p.skip_top_level_stmt()
+		p.skip_next_decl = false
+		return flat.empty_node
 	}
 	return p.top_level_stmt()
 }
 
+fn (mut p Parser) consume_decl_prefix_after_attrs() {
+	for p.tok == .semicolon || p.tok == .attribute || p.tok == .lsbr {
+		if p.tok == .semicolon {
+			p.next()
+			continue
+		}
+		p.skip_attrs()
+	}
+}
+
+fn (mut p Parser) cur_decl_is_fn() bool {
+	if p.tok == .key_fn {
+		return true
+	}
+	return p.tok == .key_pub && p.peek() == .key_fn
+}
+
 fn (mut p Parser) fn_decl() flat.NodeId {
 	p.check(.key_fn)
 	mut name := ''

vlib/v3/tests/type_checker_errors_test.v

@@ -222,6 +222,9 @@ fn test_type_checker_reports_core_semantic_errors() {
 		'moda/moda.v': 'module moda\n\n__global hit int\n\nstruct Tracer {}\n\n@[if trace ?]\nfn (t Tracer) trace(x int) {}\n\nfn side_effect() int {\n\thit = 99\n\treturn 1\n}\n\npub fn run() int {\n\tt := Tracer{}\n\tt.trace(side_effect())\n\treturn hit\n}\n'
 	}, 'main.v')
 	assert disabled_if_method_out == '0'
+	disabled_if_non_fn_out := run_good(v3_bin, 'disabled_if_non_fn_decl_skipped',
+		'@[if trace ?]\nstruct DisabledStruct {\n\tbad MissingDisabledType\n}\n\nstruct EnabledStruct {\n\tvalue int\n}\n\nfn main() {\n\tprintln(int_str(EnabledStruct{value: 7}.value))\n}\n')
+	assert disabled_if_non_fn_out == '7'
 	cross_module_array_append_c := gen_c_project(v3_bin, 'array_append_distinct_module_types', {
 		'main.v':      'module main\n\nimport moda\nimport modb\n\nfn main() {\n\tmut xs := []moda.Foo{}\n\tys := []modb.Foo{}\n\txs << ys\n}\n'
 		'moda/moda.v': 'module moda\n\nstruct Foo {\n\ta int\n}\n'