fix typeof incorrectly propagating implicit types

test/basic/case_inside_cast.sv

@@ -0,0 +1,17 @@
+module top;
+    typedef logic [1:0] T;
+    function automatic [1:0] flip;
+        input [1:0] inp;
+        flip = ~inp;
+    endfunction
+    initial begin
+        case (flip(2'b00)) inside
+            2'b11: $display("good");
+            default: $display("default");
+        endcase
+        case (T'(flip(2'b00))) inside
+            2'b11: $display("good");
+            default: $display("default");
+        endcase
+    end
+endmodule

test/basic/case_inside_cast.v

@@ -0,0 +1,6 @@
+module top;
+    initial begin
+        $display("good");
+        $display("good");
+    end
+endmodule