Revert #1277; unfortunately seems to leak misconfigured types, causing hard to debug (spooky action in distance) fails -- will redo for 2.8

Author: cowtowncoder

release-notes/VERSION

@@ -8,8 +8,6 @@ Project: jackson-databind
 
 #1215: Problem with type specialization for Maps with `@JsonDeserialize(as=subtype)`
  (reported by brentryan@github)
-#1277: Inefficient resolution of parametrized types
- (reported by Andriy P, plokhotnyuk@github)
 #1279: Ensure DOM parsing defaults to not expanding external entities
 
 2.7.5 (11-Jun-2016)

src/main/java/com/fasterxml/jackson/databind/type/TypeFactory.java

@@ -1171,12 +1171,11 @@ protected JavaType _fromClass(ClassStack context, Class<?> rawType, TypeBindings
         if ((bindings == null) || bindings.isEmpty()) {
             key = rawType;
             result = _typeCache.get(key); // ok, cache object is synced
+            if (result != null) {
+                return result;
+            }
         } else {
-            key = bindings.asKey(rawType);
-        }
-        result = _typeCache.get(key); // ok, cache object is synced
-        if (result != null) {
-            return result;
+            key = null;
         }
 
         // 15-Oct-2015, tatu: recursive reference?
@@ -1236,7 +1235,9 @@ else if (superClass != null) {
             }
         }
         context.resolveSelfReferences(result);
-        _typeCache.putIfAbsent(key, result); // cache object syncs
+        if (key != null) {
+            _typeCache.putIfAbsent(key, result); // cache object syncs
+        }
         return result;
     }