diff --git a/core/odin/parser/parser.odin b/core/odin/parser/parser.odin
index 03fb4d66d..715b96d84 100644
--- a/core/odin/parser/parser.odin
+++ b/core/odin/parser/parser.odin
@@ -689,7 +689,12 @@ parse_when_stmt :: proc(p: ^Parser) -> ^ast.When_Stmt {
 
 	prev_level := p.expr_level
 	p.expr_level = -1
+	prev_allow_in_expr := p.allow_in_expr
+	p.allow_in_expr = true
+
 	cond = parse_expr(p, false)
+
+	p.allow_in_expr = prev_allow_in_expr
 	p.expr_level = prev_level
 
 	if cond == nil {
diff --git a/src/parser.cpp b/src/parser.cpp
index 0e971f792..b1a179573 100644
--- a/src/parser.cpp
+++ b/src/parser.cpp
@@ -4573,9 +4573,12 @@ gb_internal Ast *parse_when_stmt(AstFile *f) {
 
 	isize prev_level = f->expr_level;
 	f->expr_level = -1;
+	bool prev_allow_in_expr = f->allow_in_expr;
+	f->allow_in_expr = true;
 
 	cond = parse_expr(f, false);
 
+	f->allow_in_expr = prev_allow_in_expr;
 	f->expr_level = prev_level;
 
 	if (cond == nullptr) {