fmt: fix support for `mut static x := 42`

vlib/v/checker/tests/static_vars_in_translated_mode.out

@@ -1,4 +1,4 @@
-vlib/v/checker/tests/static_vars_in_translated_mode.vv:2:13: error: static variables are supported only in -translated mode
+vlib/v/checker/tests/static_vars_in_translated_mode.vv:2:13: error: static variables are supported only in -translated mode or in [unsafe] fn
     1 | fn counter() int {
     2 |     mut static icounter := 0
       |                ~~~~~~~~

vlib/v/checker/tests/static_vars_in_translated_mode.vv

@@ -1,6 +1,5 @@
-[unsafe]
 fn counter() int {
-	static icounter := 0
+	mut static icounter := 0
 	icounter++
 	return icounter
 }

vlib/v/fmt/fmt.v

@@ -1221,6 +1221,10 @@ pub fn (mut f Fmt) ident(node ast.Ident) {
 		if node.info.is_mut {
 			f.write(node.info.share.str() + ' ')
 		}
+		var_info := node.var_info()
+		if var_info.is_static {
+			f.write('static ')
+		}
 	}
 	f.write_language_prefix(node.language)
 	if node.name == 'it' && f.it_name != '' && !f.inside_lambda { // allow `it` in lambdas
@@ -2315,10 +2319,6 @@ pub fn (mut f Fmt) assign_stmt(node ast.AssignStmt) {
 	f.comments(node.comments, {})
 	for i, left in node.left {
 		if left is ast.Ident {
-			var_info := left.var_info()
-			if var_info.is_static {
-				f.write('static ')
-			}
 			f.expr(left)
 		} else {
 			f.expr(left)

vlib/v/fmt/tests/static_mut_keep.vv

@@ -0,0 +1,12 @@
+[unsafe]
+fn foo() int {
+	mut static x := 42
+	x++
+	return x
+}
+
+[unsafe]
+fn foo() int {
+	static x := 42 // a immutable static is not very useful, but vfmt should support that too
+	return x
+}

vlib/v/parser/assign.v

@@ -154,7 +154,7 @@ fn (mut p Parser) partial_assign_stmt(left []ast.Expr, left_comments []ast.Comme
 						name: lx.name
 						expr: if left.len == right.len { right[i] } else { ast.Expr{} }
 						share: share
-						is_mut: lx.is_mut || p.inside_for || is_static
+						is_mut: lx.is_mut || p.inside_for
 						pos: lx.pos
 					}
 					if p.pref.autofree {

vlib/v/tests/static_vars_test.v

@@ -1,6 +1,6 @@
 [unsafe]
 fn foo() int {
-	static x := 42
+	mut static x := 42
 	x++
 	return x
 }