Disallow trying to autorecover to a complex type

.release-notes/4124.md

@@ -20,3 +20,5 @@ primitive Bar
 You'd get compilation errors "argument not assignable to parameter" and "right side must be a subtype of left side" for the two lines in `Main.create()`.
 
 We've added checks to see if the constructor expressions can be implicitly auto-recovered, and if they can, no compilation error is generated.
+
+This only applies to cases where the type of the parameter (or the `let` binding) is a simple type, i.e. not a union, intersection or tuple type.

src/libponyc/expr/call.c

@@ -198,6 +198,10 @@ static ast_t* method_receiver_type(ast_t* method);
 
 bool check_auto_recover_newref(ast_t* param_type, ast_t* ast)
 {
+  // we're not going to try auto-recovering to a complex type
+  if (ast_id(param_type) != TK_NOMINAL)
+    return false;
+
   while (ast != NULL && ast_id(ast) != TK_CALL)
     ast = ast_child(ast);
 
@@ -208,7 +212,7 @@ bool check_auto_recover_newref(ast_t* param_type, ast_t* ast)
   if (ast_id(newref) != TK_NEWREF)
     return false;
 
-  // sometimes newrefs are nested?
+  // sometimes for assignments there's a nested newref
   ast_t* child = ast_child(newref);
   if (child != NULL && ast_id(child) == TK_NEWREF)
     newref = child;

test/libponyc/recover.cc

@@ -778,3 +778,22 @@ TEST_F(RecoverTest, CantAutoRecover_CtorAssignmentWithNonSendableArg)
 
   TEST_ERRORS_1(src, "right side must be a subtype of left side");
 }
+TEST_F(RecoverTest, CantAutoRecover_CtorParamToComplexTypeWithNonSendableArg)
+{
+  const char* src =
+    "actor Main\n"
+    "  new create(env: Env) =>\n"
+    "    let bar: (Foo iso | String ref) = Foo.from_u8(123)\n"
+
+    "class Foo\n"
+    "  new from_u8(v: U8) =>\n"
+    "    None\n"
+    "  new from_str(s: String ref) =>\n"
+    "    None\n"
+
+    "primitive Bar\n"
+    "  fun take_foo(foo: Foo iso) =>\n"
+    "    None\n";
+
+  TEST_ERRORS_1(src, "right side must be a subtype of left side");
+}