fix(semantic): create root symbol for @this()

.vscode/launch.json

@@ -6,13 +6,11 @@
     "configurations": [
         {
             "name": "zlint",
-            "type": "lldb-mi",
+            "type": "lldb",
             "request": "launch",
-            "target": "./zig-out/bin/zlint",
+            "program": "./zig-out/bin/zlint",
             "cwd": "${workspaceRoot}",
-            "valuesFormatting": "parseText"
         },
-
         {
             "name": "zlint --print-ast",
             "type": "lldb",
@@ -21,6 +19,13 @@
             "program": "${workspaceRoot}/zig-out/bin/zlint",
             "cwd": "${workspaceRoot}",
             "preLaunchTask": "build"
-        }
+        },
+        {
+            "name": "test-e2e",
+            "type": "lldb",
+            "request": "launch",
+            "program": "./zig-out/bin/test-e2e",
+            "cwd": "${workspaceRoot}",
+        },
     ]
 }

build.zig

@@ -128,15 +128,18 @@ pub fn build(b: *std.Build) void {
             .optimize = optimize,
         });
         e2e_tests.root_module.addImport("zlint", zlint);
+        b.installArtifact(e2e_tests);
 
         // e2e_tests.linkLibrary(lib);
         // e2e_tests.
 
         const run_e2e_tests = b.addRunArtifact(e2e_tests);
+        run_e2e_tests.step.dependOn((b.getInstallStep()));
         if (b.args) |args| {
             run_e2e_tests.addArgs(args);
         }
         const e2e_step = b.step("test-e2e", "Run end-to-end tests");
+
         e2e_step.dependOn(&lib.step);
         e2e_step.dependOn(&run_e2e_tests.step);
     }

src/semantic.zig

@@ -64,6 +64,8 @@ pub const Builder = struct {
         // initialize root scope
         try builder.enterRootScope();
         builder.assertRootScope(); // sanity check
+        const root_symbol_id = try builder.declareSymbol(Semantic.ROOT_NODE_ID, "@This()", .public, .{ .s_const = true });
+        try builder.enterContainerSymbol(root_symbol_id);
 
         // Zig guarantees that the root node ID is 0. We should be careful- they may decide to change this contract.
         // if (builtin.mode == .Debug) {
@@ -312,6 +314,9 @@ pub const Builder = struct {
     /// Unconditionally get the most recent container symbol. Panics if no
     /// symbol has been entered.
     inline fn currentContainerSymbolUnwrap(self: *const Builder) Symbol.Id {
+        if (IS_DEBUG and self._symbol_stack.items.len == 0) {
+            std.debug.panic("Cannot get current container symbol: symbol stack is empty", .{});
+        }
         return self._symbol_stack.getLast();
     }
 

src/semantic/Semantic.zig

@@ -21,6 +21,7 @@ _gpa: Allocator,
 _arena: ArenaAllocator,
 
 pub const ROOT_SCOPE_ID: Scope.Id = 0;
+pub const ROOT_NODE_ID: Ast.Node.Index = 0;
 
 pub fn deinit(self: *Semantic) void {
     // NOTE: ast is arena allocated, so no need to deinit it. freeing the arena