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, 15 insertions, 3 deletions

diff --git a/compiler.c b/compiler.c
index b691b5e..889a8dd 100644
--- a/compiler.c
+++ b/compiler.c
@@ -1869,7 +1869,7 @@ uc_compiler_declare_internal(uc_compiler *compiler, size_t srcpos, const char *n
 }
 
 static void
-uc_compiler_compile_local(uc_compiler *compiler)
+uc_compiler_compile_declexpr(uc_compiler *compiler)
 {
 	ssize_t slot;
 
@@ -1899,7 +1899,12 @@ uc_compiler_compile_local(uc_compiler *compiler)
 		}
 	}
 	while (uc_compiler_parse_match(compiler, TK_COMMA));
+}
 
+static void
+uc_compiler_compile_local(uc_compiler *compiler)
+{
+	uc_compiler_compile_declexpr(compiler);
 	uc_compiler_parse_consume(compiler, TK_SCOL);
 }
 
@@ -2218,8 +2223,15 @@ uc_compiler_compile_for_count(uc_compiler *compiler, bool local, uc_token *var)
 
 		/* If followed by a comma, continue parsing expression */
 		if (uc_compiler_parse_match(compiler, TK_COMMA)) {
-			uc_compiler_compile_expression(compiler);
-			uc_compiler_emit_insn(compiler, 0, I_POP);
+			/* Is a continuation of a declaration list... */
+			if (local) {
+				uc_compiler_compile_declexpr(compiler);
+			}
+			/* ... otherwise an unrelated expression */
+			else {
+				uc_compiler_compile_expression(compiler);
+				uc_compiler_emit_insn(compiler, 0, I_POP);
+			}
 		}
 	}
 	/* ... otherwise try parsing an entire expression (which might be absent) */