Properly propagate upper bounds through ternaries

Author: jaskarth

src/org/jetbrains/java/decompiler/modules/decompiler/exps/FunctionExprent.java

@@ -370,8 +370,12 @@ public CheckTypesResult checkExprTypeBounds() {
       case TERNARY:
         VarType supertype = getExprType();
         result.addExprLowerBound(param1, VarType.VARTYPE_BOOLEAN);
+        result.addExprUpperBound(param1, VarType.VARTYPE_BOOLEAN);
+
         result.addExprLowerBound(param2, VarType.findFamilyBottom(supertype.typeFamily));
         result.addExprLowerBound(lstOperands.get(2), VarType.findFamilyBottom(supertype.typeFamily));
+        result.addExprUpperBound(param2, supertype);
+        result.addExprUpperBound(lstOperands.get(2), supertype);
         break;
       case I2L:
       case I2F:

src/org/jetbrains/java/decompiler/modules/decompiler/vars/VarTypeProcessor.java

@@ -249,6 +249,7 @@ private boolean changeVarExprentType(Exprent exprent, VarType newType, Bound bou
         // Already have a type? Find the lower of the two; the upper bound falls.
         newMaxType = VarType.meet(currentMaxType, newType);
       }
+      ValidationHelper.assertTrue(newMaxType != null, "Trying to lower the maximum type of disjoint variables!");
 
       upperBounds.put(pair, newMaxType);
     }

testData/results/pkg/TestReturnTernaryChar.dec

@@ -12,6 +12,12 @@ public class TestReturnTernaryChar {
    public int testByteChar(String input) {
       return "hello".equals(input) ? 34 : 21;// 13
    }
+
+   public int get(int v) {
+      int w = v == 0 ? 36009 : v;// 17
+      System.out.println(w);// 18
+      return w;// 19
+   }
 }
 
 class 'pkg/TestReturnTernaryChar' {
@@ -67,9 +73,32 @@ class 'pkg/TestReturnTernaryChar' {
       f      12
       10      12
    }
+
+   method 'get (I)I' {
+      0      16
+      1      16
+      2      16
+      3      16
+      4      16
+      5      16
+      9      16
+      a      16
+      b      17
+      c      17
+      d      17
+      e      17
+      f      17
+      10      17
+      11      17
+      12      18
+      13      18
+   }
 }
 
 Lines mapping:
 5 <-> 5
 9 <-> 9
 13 <-> 13
+17 <-> 17
+18 <-> 18
+19 <-> 19

testData/src/java8/pkg/TestReturnTernaryChar.java

@@ -12,4 +12,10 @@ public int testShortChar(String input) {
     public int testByteChar(String input) {
         return "hello".equals(input) ? 34 : 21;
     }
+
+    public int get(int v) {
+      int w = v == 0 ? 36009 : v;
+      System.out.println(w);
+      return w;
+    }
 }