checker: remove vweb unused vars (#8180)

vlib/v/checker/checker.v

@@ -73,6 +73,7 @@ mut:
 	loop_label                       string // set when inside a labelled for loop
 	timers                           &util.Timers = util.new_timers(false)
 	comptime_fields_type             map[string]table.Type
+	fn_scope                         &ast.Scope = voidptr(0)
 }
 
 pub fn new_checker(table &table.Table, pref &pref.Preferences) Checker {
@@ -3584,6 +3585,19 @@ fn (mut c Checker) comptime_call(mut node ast.ComptimeCall) table.Type {
 		}
 		mut c2 := new_checker(c.table, pref2)
 		c2.check(node.vweb_tmpl)
+		mut i := 0 // tmp counter var for skipping first three tmpl vars
+		for k, _ in c2.file.scope.children[0].objects {
+			if i < 4 {
+				// Skip first three because they are tmpl vars see vlib/vweb/tmpl/tmpl.v
+				i++
+				continue
+			}
+			if k in c.fn_scope.objects && c.fn_scope.objects[k] is ast.Var {
+				mut vsc := c.fn_scope.objects[k] as ast.Var
+				vsc.is_used = true
+				c.fn_scope.objects[k] = vsc
+			}
+		}
 		c.warnings << c2.warnings
 		c.errors << c2.errors
 		c.nr_warnings += c2.nr_warnings
@@ -5319,6 +5333,7 @@ fn (mut c Checker) fn_decl(mut node ast.FnDecl) {
 			}
 		}
 	}
+	c.fn_scope = node.scope
 	c.stmts(node.stmts)
 	returns := c.returns || has_top_return(node.stmts)
 	if node.language == .v && !node.no_body && node.return_type != table.void_type && !returns &&

vlib/v/checker/tests/templates/index.html

@@ -0,0 +1 @@
+@test

vlib/v/checker/tests/vweb_tmpl_used_var.out

@@ -0,0 +1 @@
+

vlib/v/checker/tests/vweb_tmpl_used_var.vv

@@ -0,0 +1,15 @@
+import vweb
+
+struct App {
+	vweb.Context
+}
+
+pub fn (mut app App) index() vweb.Result {
+    test := 'test'
+    return $vweb.html()
+}
+
+fn main() {
+	mut app := App{}
+	vweb.run_app<App>(mut app, 8181)
+}

vlib/v/compiler_errors_test.v

@@ -11,6 +11,10 @@ const skip_files = [
 		'vlib/v/checker/tests/custom_comptime_define_if_flag.vv',
 	]
 
+const skip_on_ubuntu_musl = [
+		'vlib/v/checker/tests/vweb_tmpl_used_var.vv',
+]
+
 const turn_off_vcolors = os.setenv('VCOLORS', 'never', true)
 
 const should_autofix = os.getenv('VAUTOFIX') != ''
@@ -89,6 +93,9 @@ fn (mut tasks []TaskDescription) run() {
 	mut work := sync.new_channel<TaskDescription>(tasks.len)
 	mut results := sync.new_channel<TaskDescription>(tasks.len)
 	mut m_skip_files := skip_files.clone()
+	if os.getenv('V_CI_UBUNTU_MUSL').len > 0 {
+		m_skip_files << skip_on_ubuntu_musl
+	}
 	$if noskip ? {
 		m_skip_files = []
 	}

vlib/v/parser/comptime.v

@@ -109,9 +109,10 @@ fn (mut p Parser) comp_call() ast.ComptimeCall {
 	fn_path := p.cur_fn_name.split('_')
 	tmpl_path := if is_html { '${fn_path.last()}.html' } else { s }
 	// Looking next to the vweb program
-	dir := os.dir(p.scanner.file_path)
+	dir := os.dir(p.scanner.file_path.replace('/', os.path_separator))
-	mut path := os.join_path(dir, fn_path.join('/'))
+	mut path := os.join_path(dir, fn_path.join(os.path_separator))
 	path += '.html'
+	path = os.real_path(path)
 	if !is_html {
 		path = tmpl_path
 	}