Fix: Issue #1394 (#2266)

* start correct

* Fix #1394

* remove llvm::outs()

* Fix #1394

* ---

* fix issue-1394

* fix issue-1394

* Update explorer/interpreter/interpreter.cpp

Co-authored-by: Geoff Romer <gromer@google.com>

* fix issue-1394

* remove and rename test files

* add changes from j.m

Co-authored-by: m new <michael.burzan@outlook.de>
Co-authored-by: Geoff Romer <gromer@google.com>

explorer/testdata/function/auto_return/modify_return_type.carbon

@@ -1,18 +0,0 @@
-// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
-// Exceptions. See /LICENSE for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-// RUN: %{explorer} %s 2>&1 | %{FileCheck-strict} %s
-// RUN: %{explorer-trace} %s 2>&1 | %{FileCheck-allow-unmatched} %s
-// AUTOUPDATE: %{explorer} %s
-// CHECK:result: 0
-
-package ExplorerTest api;
-
-fn Id(t: Type) -> auto { return t; }
-
-// Test non-trivial type expression in return type.
-
-fn Main() -> Id(i32) {
-  return 0;
-}

explorer/testdata/function/auto_return/type.carbon

@@ -1,19 +0,0 @@
-// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
-// Exceptions. See /LICENSE for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-// RUN: %{explorer} %s 2>&1 | %{FileCheck-strict} %s
-// RUN: %{explorer-trace} %s 2>&1 | %{FileCheck-allow-unmatched} %s
-// AUTOUPDATE: %{explorer} %s
-// CHECK:result: 0
-
-package ExplorerTest api;
-
-fn Id(t: Type) -> auto { return t; }
-
-// Test non-trivial type expression in variable declaration statement.
-
-fn Main() -> i32 {
-  var x: Id(i32) = 0;
-  return x;
-}

explorer/testdata/function/fail_param_type_is_call.carbon

@@ -2,10 +2,9 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
-// RUN: %{explorer} %s 2>&1 | %{FileCheck-strict} %s
-// RUN: %{explorer-trace} %s 2>&1 | %{FileCheck-allow-unmatched} %s
+// RUN: %{not} %{explorer} %s 2>&1 | %{FileCheck-strict} %s
+// RUN: %{not} %{explorer-trace} %s 2>&1 | %{FileCheck-allow-unmatched} %s
 // AUTOUPDATE: %{explorer} %s
-// CHECK:result: 0
 
 package ExplorerTest api;
 
@@ -13,6 +12,7 @@ fn Id(t: Type) -> auto { return t; }
 
 // Test non-trivial type expression in parameter type.
 
+// CHECK:COMPILATION ERROR: {{.*}}/explorer/testdata/function/fail_param_type_is_call.carbon:[[@LINE+1]]: Function would be called at compile-time
 fn f(x: Id(i32)) -> i32 {
   return x;
 }

explorer/testdata/function/fail_return_type_is_call.carbon

@@ -0,0 +1,20 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+// RUN: %{not} %{explorer} %s 2>&1 2>&1 | %{FileCheck} %s
+// AUTOUPDATE: %{explorer} %s
+
+package EmptyIdentifier impl;
+
+fn apply[T:! Type, U:! Type](f: T, EmptyIdentifier: U)
+{
+match (true[true]) {}
+}
+
+// CHECK:COMPILATION ERROR: {{.*}}/explorer/testdata/function/fail_return_type_is_call.carbon:[[@LINE+1]]: Function would be called at compile-time
+fn EmptyIdentifier() -> apply(true, true);
+
+fn Main() -> i32 {
+  return 0;
+}

explorer/testdata/function/fail_var_type_is_call.carbon

@@ -0,0 +1,18 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+// RUN: %{not} %{explorer} %s 2>&1 2>&1 | %{FileCheck} %s
+// AUTOUPDATE: %{explorer} %s
+
+package EmptyIdentifier impl;
+
+fn test() -> i32 {
+  return 1;
+}
+
+fn Main() -> i32 {
+  // CHECK:COMPILATION ERROR: {{.*}}/explorer/testdata/function/fail_var_type_is_call.carbon:[[@LINE+1]]: Function would be called at compile-time
+  var x: test() = 1;
+  return 0;
+}