[vala/wip/issue/1246: 2/2] parser: Better handling of misplaced switch sections

[Rico Tzschichholz <ricotz src gnome org>]

commit 2215b53bdfa1d95e54e8363bd53e0ff834950ece
Author: Rico Tzschichholz <ricotz ubuntu com>
Date:   Tue Nov 2 13:22:00 2021 +0100

    parser: Better handling of misplaced switch sections
    
    Fixes https://gitlab.gnome.org/GNOME/vala/issues/1246

 tests/Makefile.am                               |  1 +
 tests/parser/switch-section-outside-switch.test |  5 +++++
 vala/valaparser.vala                            | 15 +++++++++++++--
 vala/valaswitchsection.vala                     |  6 ++++++
 4 files changed, 25 insertions(+), 2 deletions(-)
---
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 413132a6f..d5ddb4917 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -929,6 +929,7 @@ TESTS = \
        parser/statement-keyword-as-identifier.vala \
        parser/statement-outside-root.test \
        parser/switch-statement.vala \
+       parser/switch-section-outside-switch.test \
        parser/template.vala \
        parser/tuple.vala \
        parser/unsupported-property-async.test \
diff --git a/tests/parser/switch-section-outside-switch.test b/tests/parser/switch-section-outside-switch.test
new file mode 100644
index 000000000..8a888d83c
--- /dev/null
+++ b/tests/parser/switch-section-outside-switch.test
@@ -0,0 +1,5 @@
+Invalid Code
+
+void main () {
+       case 23:
+}
diff --git a/vala/valaparser.vala b/vala/valaparser.vala
index 02b69cc0a..76c2bc92e 100644
--- a/vala/valaparser.vala
+++ b/vala/valaparser.vala
@@ -1634,6 +1634,10 @@ public class Vala.Parser : CodeVisitor {
                        case TokenType.SWITCH:
                                stmt = parse_switch_statement ();
                                break;
+                       case TokenType.CASE:
+                       case TokenType.DEFAULT:
+                               stmt = parse_switch_section_statement ();
+                               break;
                        case TokenType.WHILE:
                                stmt = parse_while_statement ();
                                break;
@@ -1700,8 +1704,6 @@ public class Vala.Parser : CodeVisitor {
 
        void parse_statements (Block block) throws ParseError {
                while (current () != TokenType.CLOSE_BRACE
-                      && current () != TokenType.CASE
-                      && current () != TokenType.DEFAULT
                       && current () != TokenType.EOF) {
                        try {
                                Statement stmt = null;
@@ -1733,6 +1735,15 @@ public class Vala.Parser : CodeVisitor {
                                case TokenType.WITH:
                                        stmt = parse_statement (current ());
                                        break;
+                               case TokenType.CASE:
+                               case TokenType.DEFAULT:
+                                       if (block is SwitchSection) {
+                                               // begin a new switch case
+                                               return;
+                                       } else {
+                                               stmt = parse_statement (current ());
+                                       }
+                                       break;
                                case TokenType.VAR:
                                        is_decl = true;
                                        parse_local_variable_declarations (block);
diff --git a/vala/valaswitchsection.vala b/vala/valaswitchsection.vala
index af5be68dc..a44256b85 100644
--- a/vala/valaswitchsection.vala
+++ b/vala/valaswitchsection.vala
@@ -88,6 +88,12 @@ public class Vala.SwitchSection : Block {
                        return !error;
                }
 
+               if (!(parent_node is SwitchStatement)) {
+                       Report.error (source_reference, "no enclosing switch statement found");
+                       error = true;
+                       return false;
+               }
+
                foreach (SwitchLabel label in get_labels ()) {
                        label.check (context);
                }