[torque] fix assignment with operator

Change-Id: I4710d317cf9f5686551a3df6e98619bab79387fa
Reviewed-on: https://chromium-review.googlesource.com/1156698
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54827}

src/torque/implementation-visitor.cc

@@ -491,7 +491,7 @@ VisitResult ImplementationVisitor::Visit(AssignmentExpression* expr) {
         GenerateFetchFromLocation(expr->location, location_ref);
     assignment_value = Visit(expr->value);
     Arguments args;
-    args.parameters = {assignment_value, assignment_value};
+    args.parameters = {location_value, assignment_value};
     assignment_value = GenerateCall(*expr->op, args);
     GenerateAssignToLocation(expr->location, location_ref, assignment_value);
   } else {

src/torque/torque-parser.cc

@@ -702,7 +702,7 @@ base::Optional<ParseResult> MakeNameAndType(
 base::Optional<ParseResult> ExtractAssignmentOperator(
     ParseResultIterator* child_results) {
   auto op = child_results->NextAs<std::string>();
-  base::Optional<std::string> result = std::string(op.begin() + 1, op.end());
+  base::Optional<std::string> result = std::string(op.begin(), op.end() - 1);
   return ParseResult(std::move(result));
 }
 

test/torque/test-torque.tq

@@ -303,24 +303,24 @@ module test {
   // are (not) present.
   macro TestForLoop() {
     let sum: Smi = 0;
-    for (let i: Smi = 0; i < 5; ++i) sum = sum + i;
+    for (let i: Smi = 0; i < 5; ++i) sum += i;
     check(sum == 10);
 
     sum = 0;
     let j: Smi = 0;
-    for (; j < 5; ++j) sum = sum + j;
+    for (; j < 5; ++j) sum += j;
     check(sum == 10);
 
     sum = 0;
     j = 0;
-    for (; j < 5;) sum = sum + j++;
+    for (; j < 5;) sum += j++;
     check(sum == 10);
 
     // Check that break works. No test expression.
     sum = 0;
     for (let i: Smi = 0;; ++i) {
       if (i == 5) break;
-      sum = sum + i;
+      sum += i;
     }
     check(sum == 10);
 
@@ -328,7 +328,7 @@ module test {
     j = 0;
     for (;;) {
       if (j == 5) break;
-      sum = sum + j;
+      sum += j;
       j++;
     }
     check(sum == 10);
@@ -338,7 +338,7 @@ module test {
     sum = 0;
     for (let i: Smi = 0; i < 5; ++i) {
       if (i == 3) continue;
-      sum = sum + i;
+      sum += i;
     }
     check(sum == 7);
 
@@ -346,7 +346,7 @@ module test {
     j = 0;
     for (; j < 5; ++j) {
       if (j == 3) continue;
-      sum = sum + j;
+      sum += j;
     }
     check(sum == 7);
 
@@ -357,7 +357,7 @@ module test {
         j++;
         continue;
       }
-      sum = sum + j;
+      sum += j;
       j++;
     }
     check(sum == 7);
@@ -366,7 +366,7 @@ module test {
     for (let i: Smi = 0;; ++i) {
       if (i == 3) continue;
       if (i == 5) break;
-      sum = sum + i;
+      sum += i;
     }
     check(sum == 7);
 
@@ -379,7 +379,7 @@ module test {
       }
 
       if (j == 5) break;
-      sum = sum + j;
+      sum += j;
       j++;
     }
     check(sum == 7);