diff --git a/js/src/jsopcode.cpp b/js/src/jsopcode.cpp
index 415a71b1dd2..13ef7279009 100644
--- a/js/src/jsopcode.cpp
+++ b/js/src/jsopcode.cpp
@@ -5968,7 +5968,7 @@ ExpressionDecompiler::decompilePC(jsbytecode *pc)
         else
             return write("[") &&
                    quote(prop, '\'') &&
-                   write("]") >= 0;
+                   write("]");
         return true;
       }
       case JSOP_GETELEM:
@@ -6024,7 +6024,7 @@ ExpressionDecompiler::decompilePC(jsbytecode *pc)
         return write(js_this_str);
       case JSOP_CALL:
       case JSOP_FUNCALL:
-        return decompilePC(pcstack[-(GET_ARGC(pc) + 2)]) &&
+        return decompilePC(pcstack[-int32_t(GET_ARGC(pc) + 2)]) &&
                write("(...)");
       default:
         break;
diff --git a/js/src/jsscript.cpp b/js/src/jsscript.cpp
index a46b5fc885e..2b8596ac153 100644
--- a/js/src/jsscript.cpp
+++ b/js/src/jsscript.cpp
@@ -178,7 +178,7 @@ XDRScriptBindings(XDRState<mode> *xdr, LifoAllocScope &las, unsigned numArgs, un
         }
 
         for (BindingIter bi(script->bindings); bi; bi++) {
-            uint8_t u8 = (uint8_t(bi->kind()) << 1) | bi->aliased();
+            uint8_t u8 = (uint8_t(bi->kind()) << 1) | uint8_t(bi->aliased());
             if (!xdr->codeUint8(&u8))
                 return false;
         }