Fix #1186

Author: cowtowncoder

release-notes/VERSION

@@ -7,6 +7,8 @@ Project: jackson-databind
 2.7.4 (not yet released)
 
 #1178: `@JsonSerialize(contentAs=superType)` behavior disallowed in 2.7
+#1186: SimpleAbstractTypeResolver breaks generic parameters
+ (reported by tobiash@github)
 #1189: Converter called twice results in ClassCastException
  (reported by carrino@github)
 #1191: Non-matching quotes used in error message for date parsing

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

@@ -364,11 +364,12 @@ public JavaType constructSpecializedType(JavaType baseType, Class<?> subclass)
                 }
             }
             // (3) Sub-class does not take type parameters -- just resolve subtype
-            if (subclass.getTypeParameters().length == 0) {
+            int typeParamCount = subclass.getTypeParameters().length;
+            if (typeParamCount == 0) {
                 newType = _fromClass(null, subclass, TypeBindings.emptyBindings());     
                 break;
             }
-
+            
             // If not, we'll need to do more thorough forward+backwards resolution. Sigh.
             // !!! TODO (as of 28-Jan-2016, at least)
 
@@ -390,7 +391,20 @@ public JavaType constructSpecializedType(JavaType baseType, Class<?> subclass)
             if (newType == null) {
                 // But otherwise gets bit tricky, as we need to partially resolve the type hierarchy
                 // (hopefully passing null Class for root is ok)
-                newType = _fromClass(null, subclass, TypeBindings.emptyBindings());        
+                TypeBindings tb = null;
+
+                // 14-Apr-2016, tatu: One possible short-cut; if type parameter counts
+                //   match, chances are they ought to match. Let's take our chances...
+                if (baseType.containedTypeCount() == typeParamCount) {
+                    if (typeParamCount == 1) {
+                        tb = TypeBindings.create(subclass, baseType.containedType(0));
+                    } else if (typeParamCount == 2) {
+                        tb = TypeBindings.create(subclass, baseType.containedType(0),
+                                baseType.containedType(1));
+                    }
+                }
+                newType = _fromClass(null, subclass,
+                        (tb == null) ? TypeBindings.emptyBindings() : tb);
             }
         } while (false);
 

src/test/java/com/fasterxml/jackson/failing/AbstracTypeMapping1186Test.java renamed to src/test/java/com/fasterxml/jackson/databind/jsontype/AbstracTypeMapping1186Test.java

@@ -1,4 +1,4 @@
-package com.fasterxml.jackson.failing;
+package com.fasterxml.jackson.databind.jsontype;
 
 import java.util.List;