fix(check): Propagate the expected type through array expressions

check/src/typecheck.rs

@@ -646,12 +646,10 @@ impl<'a> Typecheck<'a> {
         let _ = ::rename::rename(&mut self.symbols, expr);
         self.implicit_resolver.metadata = ::metadata::metadata(&self.environment, expr).1;
 
+        let temp = expected_type.and_then(|expected| self.create_unifiable_signature(expected));
+        let expected_type = temp.as_ref().or(expected_type);
+
         let mut typ = self.typecheck_opt(expr, expected_type);
-        if let Some(expected) = expected_type {
-            let expected = self.create_unifiable_signature(expected)
-                .unwrap_or_else(|| expected.clone());
-            typ = self.subsumes_expr(expr_check_span(expr), 0, &expected, typ, expr);
-        }
         // Only the 'tail' expression need to be generalized at this point as all bindings
         // will have already been generalized
         self.generalize_variables(0, &mut [].iter_mut(), tail_expr(expr));
@@ -908,12 +906,17 @@ impl<'a> Typecheck<'a> {
                 }
             }
             Expr::Array(ref mut array) => {
-                let mut expected_type = self.subs.new_var();
+                let mut expected_element_type = self.subs.new_var();
+
+                if let Some(expected_type) = expected_type.take() {
+                    array.typ = self.type_cache.array(expected_element_type.clone());
+                    self.unify_span(expr.span, &expected_type, array.typ.clone());
+                }
+
                 for expr in &mut array.exprs {
-                    let typ = self.typecheck(expr, &expected_type);
-                    expected_type = self.unify_span(expr.span, &expected_type, typ);
+                    expected_element_type = self.typecheck(expr, &expected_element_type);
                 }
-                array.typ = self.type_cache.array(expected_type);
+
                 Ok(TailCall::Type(array.typ.clone()))
             }
             Expr::Lambda(ref mut lambda) => {

check/tests/pass.rs

@@ -820,6 +820,15 @@ fn expected_type_do_not_override_actual_type_for_returned_type() {
     assert_req!(result, Ok(typ("Int")));
 }
 
+#[test]
+fn expected_type_do_not_override_actual_type_for_returned_type_array() {
+    let text = "[1]";
+    let (_, result) = support::typecheck_expr_expected(text, Some(&Type::hole()));
+
+    assert_req!(result.map(|t| t.to_string()), Ok("Array Int"));
+}
+
+
 #[test]
 fn dont_guess_record_type() {
     let _ = env_logger::try_init();
@@ -835,3 +844,20 @@ let x : Test = { a = 0, b = "" }
 
     assert!(result.is_ok(), "{}", result.unwrap_err());
 }
+
+#[test]
+fn generalize_function_in_record_and_array() {
+    let _ = env_logger::try_init();
+
+    let text = r#"
+let string x : String -> String = x
+let a: Array { f : String -> String } = [
+    { f = \x -> x },
+    { f = \x -> string x },
+]
+a
+"#;
+    let result = support::typecheck(text);
+
+    assert_req!(result.map(|t| t.to_string()), Ok("Array { f : String -> String }"));
+}

repl/src/repl.glu

@@ -66,7 +66,7 @@ let make_commands cpu_pool : CpuPool -> Commands =
         | Err x -> io.println x
 
     let commands = ref []
-    let cmds = [{
+    let cmds : Array Cmd = [{
             name = "quit",
             alias = "q",
             info = "Quit the REPL",