From 3733c996bc353a513d53f8bd1b7e5dede3900f4a Mon Sep 17 00:00:00 2001
From: "K. Lange" <klange@toaruos.org>
Date: Fri, 23 Apr 2021 14:15:14 +0900
Subject: [PATCH] Fix assignments to single complex assignment targets
 (trailing commas)

---
 src/compiler.c                                | 12 +++++++++---
 test/testSingularExpandedAssignment.krk       | 19 +++++++++++++++++++
 .../testSingularExpandedAssignment.krk.expect |  5 +++++
 3 files changed, 33 insertions(+), 3 deletions(-)
 create mode 100644 test/testSingularExpandedAssignment.krk
 create mode 100644 test/testSingularExpandedAssignment.krk.expect

diff --git a/src/compiler.c b/src/compiler.c
index b32afc6..24969dd 100644
--- a/src/compiler.c
+++ b/src/compiler.c
@@ -1891,9 +1891,11 @@ static void forStatement(void) {
 	beginScope();
 
 	ssize_t loopInd = current->localCount;
+	int sawComma = 0;
 	ssize_t varCount = 0;
 	int matchedEquals = 0;
 	do {
+		if (!check(TOKEN_IDENTIFIER)) break;
 		ssize_t ind = parseVariable("Expected name for loop iterator.");
 		if (parser.hadError) return;
 		if (match(TOKEN_EQUAL)) {
@@ -1904,6 +1906,7 @@ static void forStatement(void) {
 		}
 		defineVariable(ind);
 		varCount++;
+		if (check(TOKEN_COMMA)) sawComma = 1;
 	} while (match(TOKEN_COMMA));
 
 	int loopStart;
@@ -1920,7 +1923,7 @@ static void forStatement(void) {
 		loopStart = currentChunk()->count;
 		exitJump = emitJump(OP_CALL_ITER);
 
-		if (varCount > 1) {
+		if (varCount > 1 || sawComma) {
 			EMIT_OPERAND_OP(OP_UNPACK, varCount);
 			for (ssize_t i = loopInd + varCount - 1; i >= loopInd; i--) {
 				EMIT_OPERAND_OP(OP_SET_LOCAL, i);
@@ -2675,12 +2678,15 @@ static void super_(int exprType) {
 static void comprehensionInner(KrkScanner scannerBefore, Parser parserBefore, void (*body)(size_t), size_t arg) {
 	ssize_t loopInd = current->localCount;
 	ssize_t varCount = 0;
+	int sawComma = 0;
 	do {
+		if (!check(TOKEN_IDENTIFIER)) break;
 		defineVariable(parseVariable("Expected name for iteration variable."));
 		if (parser.hadError) return;
 		emitByte(OP_NONE);
 		defineVariable(loopInd);
 		varCount++;
+		if (check(TOKEN_COMMA)) sawComma = 1;
 	} while (match(TOKEN_COMMA));
 
 	consume(TOKEN_IN, "Only iterator loops (for ... in ...) are allowed in generator expressions.");
@@ -2694,7 +2700,7 @@ static void comprehensionInner(KrkScanner scannerBefore, Parser parserBefore, vo
 	int loopStart = currentChunk()->count;
 	int exitJump = emitJump(OP_CALL_ITER);
 
-	if (varCount > 1) {
+	if (varCount > 1 || sawComma) {
 		EMIT_OPERAND_OP(OP_UNPACK, varCount);
 		for (ssize_t i = loopInd + varCount - 1; i >= loopInd; i--) {
 			EMIT_OPERAND_OP(OP_SET_LOCAL, i);
@@ -3052,7 +3058,7 @@ static void ternary(ChunkRecorder before, KrkScanner oldScanner, Parser oldParse
 static void complexAssignmentTargets(KrkScanner oldScanner, Parser oldParser, size_t targetCount, int parenthesized) {
 	emitBytes(OP_DUP, 0);
 
-	if (targetCount > 1) {
+	if (targetCount > 0) {
 		EMIT_OPERAND_OP(OP_UNPACK,targetCount);
 		EMIT_OPERAND_OP(OP_REVERSE,targetCount);
 	}
diff --git a/test/testSingularExpandedAssignment.krk b/test/testSingularExpandedAssignment.krk
new file mode 100644
index 0000000..314d6f6
--- /dev/null
+++ b/test/testSingularExpandedAssignment.krk
@@ -0,0 +1,19 @@
+let x, y, z
+
+x, = (1,)
+
+assert x == 1
+
+y, = [2]
+
+assert y == 2
+
+for a, in [(1,),(2,),(3,)]:
+    print(a)
+
+try:
+    z, = 1
+except TypeError:
+    print("okay")
+
+print(list(x * x for x, in [(1,),[2],(3,)]))
diff --git a/test/testSingularExpandedAssignment.krk.expect b/test/testSingularExpandedAssignment.krk.expect
new file mode 100644
index 0000000..a6f337f
--- /dev/null
+++ b/test/testSingularExpandedAssignment.krk.expect
@@ -0,0 +1,5 @@
+1
+2
+3
+okay
+[1, 4, 9]