fmt: fix possible removal of PrefixExpr or blocks (#9351)

vlib/v/fmt/fmt.v

@@ -764,26 +764,23 @@ pub fn (mut f Fmt) enum_decl(node ast.EnumDecl) {
 	f.writeln('}\n')
 }
 
-pub fn (mut f Fmt) prefix_expr_cast_expr(fexpr ast.Expr) {
+pub fn (mut f Fmt) prefix_expr_cast_expr(node ast.Expr) {
 	mut is_pe_amp_ce := false
-	if fexpr is ast.PrefixExpr {
-		if fexpr.right is ast.CastExpr && fexpr.op == .amp {
-			mut ce := fexpr.right as ast.CastExpr
+	if node is ast.PrefixExpr {
+		if node.right is ast.CastExpr && node.op == .amp {
+			mut ce := node.right as ast.CastExpr
 			ce.typname = f.table.get_type_symbol(ce.typ).name
 			is_pe_amp_ce = true
 			f.expr(ce)
 		}
-	} else if fexpr is ast.CastExpr {
+	} else if node is ast.CastExpr {
 		last := f.out.cut_last(1)
 		if last != '&' {
 			f.out.write_string(last)
 		}
 	}
 	if !is_pe_amp_ce {
-		f.expr(fexpr)
-		if fexpr is ast.PrefixExpr {
-			f.or_expr(fexpr.or_block)
-		}
+		f.expr(node)
 	}
 }
 
@@ -1253,6 +1250,7 @@ pub fn (mut f Fmt) postfix_expr(node ast.PostfixExpr) {
 pub fn (mut f Fmt) prefix_expr(node ast.PrefixExpr) {
 	f.write(node.op.str())
 	f.prefix_expr_cast_expr(node.right)
+	f.or_expr(node.or_block)
 }
 
 pub fn (mut f Fmt) range_expr(node ast.RangeExpr) {

vlib/v/fmt/tests/or_keep.vv

@@ -32,3 +32,9 @@ fn or_with_one_multi_line_stmt() {
 		}
 	}
 }
+
+fn channel_pop() {
+	var_init := <-ch or { -1.25 }
+	var_assign = <-ch or { -2.5 }
+	arr_push << <-ch or { -3.75 }
+}