Fix cases where previous valid generic mappings for lambdas would get…

… overwritten with subtly incorrect ones
Vineflower · Sep 6, 2023 · 13d4112 · 13d4112
1 parent 26088d3
commit 13d4112
Show file tree

Hide file tree

Showing 4 changed files with 68 additions and 34 deletions.
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/ExprProcessor.java b/src/org/jetbrains/java/decompiler/modules/decompiler/ExprProcessor.java
@@ -1057,6 +1057,10 @@ public static boolean doGenericTypesCast(VarType left, VarType right) {
     }
 
     if (left.isGeneric() && right.isGeneric()) {
+      if (shouldGenericTypesCast(left, right)) {
+        return true;
+      }
+
       GenericType leftGeneric = (GenericType) left;
       GenericType rightGeneric = (GenericType) right;
 
@@ -1072,42 +1076,50 @@ public static boolean doGenericTypesCast(VarType left, VarType right) {
         }
 
         if (leftType != null) {
-          if (leftType.isGeneric()) {
-            if (rightType.isGeneric()) {
-              if (leftType.isSuperset(rightType)) {
-                // Casting Clazz<?> to Clazz<T> or Clazz<Concrete>
-                if ((((GenericType) leftType).getWildcard() == GenericType.WILDCARD_NO || ((GenericType) leftType).getWildcard() == GenericType.WILDCARD_EXTENDS) &&
-                  ((GenericType) rightType).getWildcard() == GenericType.WILDCARD_SUPER) {
-
-                  boolean ok = true;
-                  if (((GenericType) leftType).getWildcard() == GenericType.WILDCARD_EXTENDS) {
-                    // Equals, ignoring wildcards
-                    if (!((GenericType) leftType).getArguments().isEmpty() && !((GenericType) rightType).getArguments().isEmpty() &&
-                      leftType.equals(rightType)) {
-                      ok = false;
-                    }
-                  }
+          if (shouldGenericTypesCast(leftType, rightType)) {
+            return true;
+          }
+        }
+      }
+    }
 
-                  if (ok) {
-                    return true;
-                  }
-                }
-              }
+    return false;
+  }
 
-              if ((((GenericType) leftType).getWildcard() == GenericType.WILDCARD_NO || ((GenericType) leftType).getWildcard() == GenericType.WILDCARD_SUPER) &&
-                ((GenericType) rightType).getWildcard() == GenericType.WILDCARD_EXTENDS) {
-                return true;
-              }
-            } else {
-              // Right is not generic
-              // Check for casting a concrete rightType to a specific left generic
-              // e.g. (List<T>)list where 'list' is List<Object>
-              if (((GenericType) leftType).getWildcard() == GenericType.WILDCARD_NO && ((GenericType) leftType).getArguments().isEmpty()) {
-                return true;
+  private static boolean shouldGenericTypesCast(VarType leftType, VarType rightType) {
+    if (leftType.isGeneric()) {
+      if (rightType.isGeneric()) {
+        if (leftType.isSuperset(rightType)) {
+          // Casting Clazz<?> to Clazz<T> or Clazz<Concrete>
+          if ((((GenericType) leftType).getWildcard() == GenericType.WILDCARD_NO || ((GenericType) leftType).getWildcard() == GenericType.WILDCARD_EXTENDS) &&
+            ((GenericType) rightType).getWildcard() == GenericType.WILDCARD_SUPER) {
+
+            boolean ok = true;
+            if (((GenericType) leftType).getWildcard() == GenericType.WILDCARD_EXTENDS) {
+              // Equals, ignoring wildcards
+              if (!((GenericType) leftType).getArguments().isEmpty() && !((GenericType) rightType).getArguments().isEmpty() &&
+                leftType.equals(rightType)) {
+                ok = false;
               }
             }
+
+            if (ok) {
+              return true;
+            }
           }
         }
+
+        if ((((GenericType) leftType).getWildcard() == GenericType.WILDCARD_NO || ((GenericType) leftType).getWildcard() == GenericType.WILDCARD_SUPER) &&
+          ((GenericType) rightType).getWildcard() == GenericType.WILDCARD_EXTENDS) {
+          return true;
+        }
+      } else {
+        // Right is not generic
+        // Check for casting a concrete rightType to a specific left generic
+        // e.g. (List<T>)list where 'list' is List<Object>
+        if (((GenericType) leftType).getWildcard() == GenericType.WILDCARD_NO && ((GenericType) leftType).getArguments().isEmpty()) {
+          return true;
+        }
       }
     }
 

diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/exps/NewExprent.java b/src/org/jetbrains/java/decompiler/modules/decompiler/exps/NewExprent.java
@@ -216,7 +216,17 @@ else if (method.getSignature() != null || !desc.ret.equals(VarType.VARTYPE_OBJEC
                 boolean add = current == null || returnType == null || returnType.isGeneric() ||
                   (!returnType.equals(genericsMap.get(key)) && (current.type != CodeConstants.TYPE_GENVAR || !named.containsKey(current)));
                 if (add) {
-                  genericsMap.put(key, returnType);
+                  VarType prior = genericsMap.get(key);
+                  boolean addToMap = true;
+                  if (prior != null) {
+                    if (prior.isGeneric() && !((GenericType)prior).isTypeUnfinished() && DecompilerContext.getStructContext().instanceOf(returnType.value, prior.value)) {
+                      addToMap = false;
+                    }
+                  }
+
+                  if (addToMap) {
+                    genericsMap.put(key, returnType);
+                  }
                 }
               }
             }

diff --git a/src/org/jetbrains/java/decompiler/struct/gen/generics/GenericType.java b/src/org/jetbrains/java/decompiler/struct/gen/generics/GenericType.java
@@ -405,6 +405,18 @@ public boolean equalsExact(Object o) {
     return this.argumentsEqual(gt);
   }
 
+  // returns true if there's any genvars abound with empty names
+  // TODO: this is a hack! check why genvars with empty names are made!
+  public boolean isTypeUnfinished() {
+    for (GenericType gv : this.getAllGenericVars()) {
+      if (gv.value.isEmpty()) {
+        return true;
+      }
+    }
+
+    return false;
+  }
+
   public boolean argumentsEqual(GenericType gt) {
     if (arguments.size() != gt.arguments.size()) {
       return false;

diff --git a/testData/results/pkg/TestGenericsHierarchy.dec b/testData/results/pkg/TestGenericsHierarchy.dec
@@ -15,8 +15,8 @@ public class TestGenericsHierarchy<T extends Number> {
       }
 
       V v1 = list.get(0);// 18
-      T v2 = list2.get(0);// 19
-      list3.add(list2.get(0));// 21
+      T v2 = (T)list2.get(0);// 19
+      list3.add((T)list2.get(0));// 21
       this.field = (T)v;// 23
       this.setField((T)v);// 24
    }// 25
@@ -110,4 +110,4 @@ Lines mapping:
 24 <-> 21
 25 <-> 22
 39 <-> 25
-40 <-> 26
+40 <-> 26