stmt: add failing test for assignment expressions (need hoisting)

README.md

@@ -34,6 +34,9 @@ The goal is to produce idiomatic, maintainable Go code as part of a one-off conv
 [ ] `instanceof`
 [ ] `try`/`catch`/`finally`
 [ ] Abandon upon sight of `eval` / `extract` / ...
+[ ] Assignment expressions 
+	- Go doesn't support assignment in rvalues, only as a statement
+	- When walking below stmt level, need to first fully walk and check for any function calls + assignments that may need hoisting (and we can probably only do that correctly if there is no short-circuiting)
 [ ] Closures
 	- [ ] Handle value/reference captures
 [ ] Sort callbacks

fixtures/0006-expression-assignment.php

@@ -0,0 +1,11 @@
+<?php
+
+function Bar(): ?\stdClass {
+	return new \stdClass();
+}
+
+if ( ($f = Bar()) !== null) {
+	var_dump($f);
+} else {
+	echo "x\n";
+}

node.go

@@ -968,11 +968,20 @@ func (this *conversionState) convertBinaryCommon(left, right node.Node, goBinary
 	if err != nil {
 		return "", parseErr{left, err}
 	}
+
 	rhs, err := this.convert(right)
 	if err != nil {
 		return "", parseErr{right, err}
 	}
 
+	// In case of an rvalue assignment expression, we need extra parens
+	if _, ok := left.(*assign.Assign); ok {
+		lhs = "(" + lhs + ")"
+	}
+	if _, ok := right.(*assign.Assign); ok {
+		rhs = "(" + rhs + ")"
+	}
+
 	return "(" + lhs + " " + goBinaryOperator + " " + rhs + ")", nil
 }