[wasm] Check that type intersections don't yield empty.

test/mjsunit/wasm/asm-wasm.js

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Flags: --expose-wasm
 
 function assertWasm(expected, func, ffi) {
   print("Testing " + func.name + "...");
   assertEquals(expected, Wasm.instantiateModuleFromAsm(
       func.toString(), ffi).caller());
@@ skipping 664 matching lines @@
       return 28;
     }
     return 0;
   }
 
   return {caller:caller};
 }
 
 assertWasm(28, TestModDoubleNegative);
 
+
 (function () {
 function TestNamedFunctions() {
   "use asm";
 
   var a = 0.0;
   var b = 0.0;
 
   function add() {
     return +(a + b);
   }
 
   function init() {
     a = 43.25;
     b = 34.25;
   }
 
   return {init:init,
           add:add};
 }
 
 var module = Wasm.instantiateModuleFromAsm(TestNamedFunctions.toString());
 module.init();
 assertEquals(77.5, module.add());
 })();
 
+
 (function () {
 function TestGlobalsWithInit() {
   "use asm";
 
   var a = 43.25;
   var b = 34.25;
 
   function add() {
     return +(a + b);
   }
@@ skipping 631 matching lines @@
       return ((a * 3) + (4 * a)) | 0;
     }
     return {func: func};
   }
 
   var m = Wasm.instantiateModuleFromAsm(Module.toString());
   assertEquals(7, m.func());
 })();
 
 
+(function TestBadAssignDoubleFromIntish() {
+  function Module(stdlib, foreign, heap) {
+    "use asm";
+    function func() {
+      var a = 1;
+      var b = 3.0;
+      b = a;
+    }
+    return {func: func};
+  }
+  assertThrows(function() {
+    Wasm.instantiateModuleFromAsm(Module.toString());
+  });
+})();
+
+
+(function TestBadAssignIntFromDouble() {
+  function Module(stdlib, foreign, heap) {
+    "use asm";
+    function func() {
+      var a = 1;
+      var b = 3.0;
+      a = b;
+    }
+    return {func: func};
+  }
+  assertThrows(function() {
+    Wasm.instantiateModuleFromAsm(Module.toString());
+  });
+})();
+
+
 (function TestBadMultiplyIntish() {
   function Module(stdlib, foreign, heap) {
     "use asm";
     function func() {
       var a = 1;
       return ((a + a) * 4) | 0;
     }
     return {func: func};
   }
   assertThrows(function() {
@@ skipping 118 matching lines @@
       u0xffffffff: u0xffffffff,
       u0x80000000: u0x80000000,
       u0x87654321: u0x87654321,
     };
   }
   var wasm = Wasm.instantiateModuleFromAsm(asmModule.toString());
   assertEquals(0xffffffff, wasm.u0xffffffff());
   assertEquals(0x80000000, wasm.u0x80000000());
   assertEquals(0x87654321, wasm.u0x87654321());
 })();