parser: port zig fmt on/off in middle of code tests

Port tests:
- "'zig fmt: (off|on)' works in the middle of code"
- "'zig fmt: on' indentation is unchanged"

Handle block-terminated expressions (if, while) that don't need
semicolons by checking if previous token was '}'.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

parser.c

@@ -2017,6 +2017,10 @@ static AstNodeIndex expectVarDeclExprStatement(Parser* p) {
             // Expression that doesn't need semicolon (block-terminated)
             return lhs;
         default: {
+            // Check if expression ended with a block (previous token is })
+            // and thus doesn't need a semicolon
+            if (p->token_tags[p->tok_i - 1] == TOKEN_R_BRACE)
+                return lhs;
             const AstNodeTag assign_tag = assignOpTag(p->token_tags[p->tok_i]);
             if (assign_tag == AST_NODE_ROOT) {
                 fprintf(stderr,

parser_test.zig

@@ -1869,6 +1869,53 @@ test "zig fmt: doc and line comment following 'zig fmt: on'" {
     );
 }
 
+test "zig fmt: 'zig fmt: (off|on)' works in the middle of code" {
+    try testTransform(
+        \\test "" {
+        \\    const x = 42;
+        \\
+        \\    if (foobar) |y| {
+        \\    // zig fmt: off
+        \\            }// zig fmt: on
+        \\
+        \\    const  z  = 420;
+        \\}
+        \\
+    ,
+        \\test "" {
+        \\    const x = 42;
+        \\
+        \\    if (foobar) |y| {
+        \\        // zig fmt: off
+        \\            }// zig fmt: on
+        \\
+        \\    const z = 420;
+        \\}
+        \\
+    );
+}
+
+test "zig fmt: 'zig fmt: on' indentation is unchanged" {
+    try testCanonical(
+        \\fn initOptionsAndLayouts(output: *Output, context: *Context) !void {
+        \\    // zig fmt: off
+        \\    try output.main_amount.init(output, "main_amount"); errdefer optput.main_amount.deinit();
+        \\    try output.main_factor.init(output, "main_factor"); errdefer optput.main_factor.deinit();
+        \\    try output.view_padding.init(output, "view_padding"); errdefer optput.view_padding.deinit();
+        \\    try output.outer_padding.init(output, "outer_padding"); errdefer optput.outer_padding.deinit();
+        \\    // zig fmt: on
+        \\
+        \\    // zig fmt: off
+        \\    try output.top.init(output, .top); errdefer optput.top.deinit();
+        \\    try output.right.init(output, .right); errdefer optput.right.deinit();
+        \\    try output.bottom.init(output, .bottom); errdefer optput.bottom.deinit();
+        \\    try output.left.init(output, .left); errdefer optput.left.deinit();
+        \\        // zig fmt: on
+        \\}
+        \\
+    );
+}
+
 test "zig fmt: pointer of unknown length" {
     try testCanonical(
         \\fn foo(ptr: [*]u8) void {}