Improve lvalue handling in the compiler. #1357

releasenotes.md

@@ -13,6 +13,7 @@
 - Converting a slice to a vector/array would copy too little data.
 - Crash when reading an empty 'manifest.json'.
 - "optsize" did not work correctly in project.json.
+- `l[0].a = 1` now supported for overloads due to better lvalue handling #1357.
 
 ### Stdlib changes
 - Additional init functions for hashmap.

src/compiler/sema_expr.c

@@ -4449,7 +4449,7 @@ static inline bool sema_expr_analyse_access(SemaContext *context, Expr *expr, bo
 	if (missing_ref) *missing_ref = false;
 
 	// 1. Resolve the left hand
-	if (!sema_analyse_expr_check(context, parent, check)) return false;
+	if (!sema_analyse_expr_check(context, parent, check != CHECK_VALUE ? CHECK_ADDRESS : CHECK_VALUE)) return false;
 
 	// 2. The right hand side may be a @ident or ident
 	Expr *child = expr->access_expr.child;

test/unit/regression/lvalue_handling.c3

@@ -0,0 +1,19 @@
+module lvalue_handling;
+import std;
+struct Foo
+{
+	int a;
+}
+def IntList = List(<Foo>);
+fn void subscript_overload() @test
+{
+	IntList x;
+	x.push({ 3 });
+	int* a = &x[0].a;
+	assert(*a == 3);
+	assert(x[0].a == 3);
+	*a = 4;
+	assert(x[0].a == 4);
+	x[0].a = 5;
+	assert(x[0].a == 5);
+}