Again reland "Refine expression typing, esp. by propagating range information."

src/compiler/typer.h

Index: src/compiler/typer.h
diff --git a/src/compiler/typer.h b/src/compiler/typer.h
index 2adbab5ff7002505e39484277cdc8be98cb7a62e..3b37a922341703885a6794c30bffa18be1f9854b 100644
--- a/src/compiler/typer.h
+++ b/src/compiler/typer.h
@@ -36,6 +36,17 @@ class Typer {
   class WidenVisitor;
 
   Zone* zone_;
+  Type* negative_signed32;
+  Type* non_negative_signed32;
+  Type* undefined_or_null;
+  Type* singleton_false;
+  Type* singleton_true;
+  Type* singleton_zero;
+  Type* singleton_one;
+  Type* zero_or_one;
+  Type* zeroish;
+  Type* falsish;
+  Type* integer;
   Type* number_fun0_;
   Type* number_fun1_;
   Type* number_fun2_;