Fixes for clashing variable renaming (#378)

* Add missing inherited name propagation to remapClashingNames

* Add and update test

* commit inner class file

* Update for rebase

* Handle anonymous classes in iterateClashingExprent

* Update tests

* Don't add inherited names

* fix param index for anon classes

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

@@ -1628,6 +1628,59 @@ private void iterateClashingExprent(Statement stat, StructMethod mt, Map<Stateme
             }
           }
         }
+      } else if (!newExprent.isLambda() && newExprent.isAnonymous()) {
+        ClassNode node = DecompilerContext.getClassProcessor().getMapRootClasses().get(newExprent.getNewType().value);
+        if (node != null && node.getWrapper() != null) {
+          for (String mthKey : node.getWrapper().getMethods().getLstKeys()) {
+            MethodWrapper mw = node.getWrapper().getMethods().getWithKey(mthKey);
+            StructMethod mt2 = node.getWrapper().getClassStruct().getMethod(mthKey);
+            if (mt2 != null && mw != null) {
+              // Propagate current data through to method
+              VarDefinitionHelper vardef = new VarDefinitionHelper(mw.root, mt2, mw.varproc, false);
+
+              // Do lambda parameter rename
+
+              // Calculate which varversions are the parameters
+              // This gnarly logic is needed to ensure that the varversions we're looking at are parameters.
+              // Notably, lambdas can reference *outer* variables *before* params are listed, this is to handle that case.
+
+              MethodDescriptor md = mt2.methodDescriptor();
+              int start = mt2.hasModifier(CodeConstants.ACC_STATIC) ? 0 : 1;
+              final int startIdx = start;
+              for (int i = 0; i < md.params.length; i++) {
+                if (i >= startIdx) {
+                  VarVersionPair vvp = new VarVersionPair(start, 0);
+
+                  // Try to perform a rename
+                  String name = mw.varproc.getVarName(vvp);
+                  name = rename(nameMap, name);
+
+                  // Did we rename? If so, we should add it to the name map and set as clashing
+                  if (!mw.varproc.getVarName(vvp).equals(name)) {
+                    mw.varproc.setClashingName(vvp, name);
+                    nameMap.put(new VarInMethod(vvp, mt2), name);
+                  }
+                }
+
+                start += md.params[i].stackSize;
+              }
+
+              // Iterate clashing names with the lambda's body, with the context of the outer method
+              vardef.iterateClashingNames(mw.root, mt2, varDefinitions, liveVarDefs, nameMap);
+
+              for (Entry<VarVersionPair, String> e : vardef.getClashingNames().entrySet()) {
+                mw.varproc.setClashingName(e.getKey(), e.getValue());
+              }
+
+              // Pop all the variables we've seen, now that the lambda processing is done
+              for (Entry<VarInMethod, String> e : new HashSet<>(nameMap.entrySet())) {
+                if (e.getKey().mt == mt2) {
+                  nameMap.remove(e.getKey());
+                }
+              }
+            }
+          }
+        }
       }
     }
 

test/org/jetbrains/java/decompiler/SingleClassesTest.java

@@ -413,6 +413,7 @@ private void registerDefault() {
     register(JAVA_16_PREVIEW, "PermittedSubClassE", "TestSealedInterfaces");
 
     register(JAVA_8_NODEBUG, "TestDuplicateLocals");
+    register(CUSTOM, "TestConflictingLvtNamer"); // Generated by compiling, stripping LVT, and then remapping with tiny-remapper
 
     register(JAVA_8, "TestMethodHandles");
     register(JAVA_9, "TestVarHandles");

testData/results/pkg/TestConflictingLvtNamer.dec

@@ -0,0 +1,159 @@
+package pkg;
+
+import java.util.function.Supplier;
+
+public class TestConflictingLvtNamer {
+   public static Supplier<Object> method(int i, int j, int k, int l, int m, int n) {
+      int o = l - i + 1;// 12
+      int p = m - j + 1;// 13
+      int q = n - k + 1;// 14
+      int r = o * p * q;// 15
+      return () -> new Object() {// 16
+         private final TestConflictingLvtNamer.Position cursor = new TestConflictingLvtNamer.Position();
+         private int index;
+
+         void innerMethod() {
+            int ix = this.index % o;// 21
+            int jx = this.index / o;// 22
+            int kx = jx % p;// 23
+            int lx = jx / p;// 24
+            this.index++;// 25
+            this.cursor.set(i + ix, j + kx, k + lx);// 26
+         }// 27
+      };
+   }
+
+   public static final class Position {
+      public void set(int i, int j, int k) {
+      }// 8
+   }
+}
+
+class 'pkg/TestConflictingLvtNamer' {
+   method 'method (IIIIII)Ljava/util/function/Supplier;' {
+      0      6
+      1      6
+      2      6
+      3      6
+      4      6
+      5      6
+      6      6
+      7      7
+      8      7
+      9      7
+      a      7
+      b      7
+      c      7
+      d      7
+      e      7
+      f      8
+      10      8
+      11      8
+      12      8
+      13      8
+      14      8
+      15      8
+      16      8
+      17      9
+      18      9
+      19      9
+      1a      9
+      1b      9
+      1c      9
+      1d      9
+      1e      9
+      1f      9
+      20      9
+      2d      10
+   }
+
+   method 'lambda$method$0 (IIIII)Ljava/lang/Object;' {
+      d      10
+   }
+}
+
+class 'pkg/TestConflictingLvtNamer$1' {
+   method 'innerMethod ()V' {
+      0      15
+      1      15
+      2      15
+      3      15
+      5      15
+      6      15
+      7      15
+      8      15
+      9      15
+      a      16
+      b      16
+      c      16
+      d      16
+      f      16
+      10      16
+      11      16
+      12      16
+      13      16
+      14      17
+      16      17
+      17      17
+      18      17
+      19      17
+      1a      17
+      1b      18
+      1d      18
+      1e      18
+      1f      18
+      20      18
+      21      18
+      22      18
+      23      19
+      25      19
+      26      19
+      27      19
+      29      19
+      2d      20
+      2e      20
+      2f      20
+      30      20
+      32      20
+      33      20
+      34      20
+      35      20
+      36      20
+      38      20
+      39      20
+      3a      20
+      3b      20
+      3c      20
+      3e      20
+      3f      20
+      40      20
+      41      20
+      42      20
+      43      20
+      44      20
+      45      20
+      46      20
+      47      21
+   }
+}
+
+class 'pkg/TestConflictingLvtNamer$Position' {
+   method 'set (III)V' {
+      0      27
+   }
+}
+
+Lines mapping:
+8 <-> 28
+12 <-> 7
+13 <-> 8
+14 <-> 9
+15 <-> 10
+16 <-> 11
+21 <-> 16
+22 <-> 17
+23 <-> 18
+24 <-> 19
+25 <-> 20
+26 <-> 21
+27 <-> 22

testData/results/pkg/TestThrowException.dec

@@ -10,7 +10,7 @@ public class TestThrowException {
          this.r = new Runnable() {// 12
             @Override
             public void run() {
-               int a = 5;// 15
+               int ax = 5;// 15
             }// 16
          };
       }