compiler: fix local for-loop initializer variable declarations

In a loop statement like `for (let x = 1, y = 2; ...)` the initialization
statement was incorrectly interpreted as `let x = 1; y = 2` instead of the
correct `let ..., y = 2`, triggering reference error exceptions in strict
mode.

Solve the issue by continue parsing the rest of the comma expression
seqence as declaration list expression when the initializer is compiled
in local mode.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

1 files changed, 18 insertions, 0 deletions

diff --git a/tests/custom/03_bugs/24_compiler_local_for_loop_declaration b/tests/custom/03_bugs/24_compiler_local_for_loop_declaration
new file mode 100644
index 0000000..aafde55
--- /dev/null
+++ b/tests/custom/03_bugs/24_compiler_local_for_loop_declaration
@@ -0,0 +1,18 @@
+When compiling a for-loop local variable initializer expression, the compiler
+incorrectly treated subsequent declarations as global variable assignments,
+triggering reference error exceptions in strict mode.
+
+-- Expect stdout --
+1
+-- End --
+
+-- Testcase --
+{%
+	"use strict";
+
+	// The initializer expression below was incorrectly interpreted as
+	// `let x = 0; y = 1` instead of the correct `let ..., y = 1`.
+	for (let x = 0, y = 1; x < 1; x++)
+		print(y, "\n");
+%}
+-- End --