fix Issue 12902 - [ICE] Assertion failure '!ae->lengthVar' in 'expres…

…sion.c' when using `opDollar`

src/expression.c

@@ -10986,6 +10986,10 @@ Expression *AssignExp::semantic(Scope *sc)
                 if (ex->op == TOKerror)
                     return ex;
 
+                e2 = e2->semantic(sc);
+                if (e2->op == TOKerror)
+                    return e2;
+
                 Expressions *a = (Expressions *)ae->arguments->copy();
                 a->insert(0, e2);
 

src/opover.c

@@ -956,6 +956,13 @@ Expression *op_overload(Expression *e, Scope *sc)
                             return;
                         }
 
+                        e->e2 = e->e2->semantic(sc);
+                        if (e->e2->op == TOKerror)
+                        {
+                            result = e->e2;
+                            return;
+                        }
+
                         Expressions *a = (Expressions *)ae->arguments->copy();
                         a->insert(0, e->e2);
 

test/fail_compilation/ice12902.d

@@ -0,0 +1,21 @@
+/*
+TEST_OUTPUT:
+---
+fail_compilation/ice12902.d(20): Error: variable ice12902.main.__dollar type void is inferred from initializer s.opDollar(), and variables cannot be of type void
+fail_compilation/ice12902.d(20): Error: expression s.opDollar() is void and has no value
+---
+*/
+
+struct S
+{
+    void opDollar() { }
+    void opIndex() { }
+    void opIndexAssign() { }
+    void opSliceAssign() { }
+}
+
+void main()
+{
+    S s;
+    s[] = s[$];
+}