From dfb17a5f0e4cd973e5760a5de80b5dc44f759d68 Mon Sep 17 00:00:00 2001
From: svtk <svtk@unit-188.labs.intellij.net>
Date: Tue, 8 Nov 2011 16:25:04 +0400
Subject: [PATCH] KT-58 Allow finally around definite returns

---
 .../jet/lang/cfg/JetControlFlowBuilder.java   |   1 +
 .../cfg/JetControlFlowBuilderAdapter.java     |   6 +
 .../jet/lang/cfg/JetControlFlowProcessor.java |  46 +-
 .../JetControlFlowInstructionsGenerator.java  |   7 +
 .../NondeterministicJumpInstruction.java      |   2 +-
 .../jet/lang/cfg/pseudocode/Pseudocode.java   |  72 ++-
 compiler/testData/cfg/Finally.instructions    | 573 ++++++++++++------
 compiler/testData/cfg/Finally.jet             |  58 ++
 .../full/regression/kt58.jet                  |  91 +++
 .../jetbrains/jet/cfg/JetControlFlowTest.java |  26 +-
 10 files changed, 654 insertions(+), 228 deletions(-)
 create mode 100644 compiler/testData/checkerWithErrorTypes/full/regression/kt58.jet

diff --git a/compiler/frontend/src/org/jetbrains/jet/lang/cfg/JetControlFlowBuilder.java b/compiler/frontend/src/org/jetbrains/jet/lang/cfg/JetControlFlowBuilder.java
index 72360b8b838..7425493651c 100644
--- a/compiler/frontend/src/org/jetbrains/jet/lang/cfg/JetControlFlowBuilder.java
+++ b/compiler/frontend/src/org/jetbrains/jet/lang/cfg/JetControlFlowBuilder.java
@@ -18,6 +18,7 @@ public interface JetControlFlowBuilder {
     Label createUnboundLabel();
 
     void bindLabel(@NotNull Label label);
+    void allowDead();
 
     // Jumps
     void jump(@NotNull Label label);
diff --git a/compiler/frontend/src/org/jetbrains/jet/lang/cfg/JetControlFlowBuilderAdapter.java b/compiler/frontend/src/org/jetbrains/jet/lang/cfg/JetControlFlowBuilderAdapter.java
index af961793212..df5470480f4 100644
--- a/compiler/frontend/src/org/jetbrains/jet/lang/cfg/JetControlFlowBuilderAdapter.java
+++ b/compiler/frontend/src/org/jetbrains/jet/lang/cfg/JetControlFlowBuilderAdapter.java
@@ -37,6 +37,12 @@ public class JetControlFlowBuilderAdapter implements JetControlFlowBuilder {
         builder.bindLabel(label);
     }
 
+    @Override
+    public void allowDead() {
+        assert builder != null;
+        builder.allowDead();
+    }
+
     @Override
     public void jump(@NotNull Label label) {
         assert builder != null;
diff --git a/compiler/frontend/src/org/jetbrains/jet/lang/cfg/JetControlFlowProcessor.java b/compiler/frontend/src/org/jetbrains/jet/lang/cfg/JetControlFlowProcessor.java
index b65c0db05c5..bc30b50af1e 100644
--- a/compiler/frontend/src/org/jetbrains/jet/lang/cfg/JetControlFlowProcessor.java
+++ b/compiler/frontend/src/org/jetbrains/jet/lang/cfg/JetControlFlowProcessor.java
@@ -5,18 +5,19 @@ import com.intellij.psi.PsiElement;
 import com.intellij.psi.tree.IElementType;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
-import org.jetbrains.jet.lang.descriptors.CallableDescriptor;
 import org.jetbrains.jet.lang.psi.*;
 import org.jetbrains.jet.lang.resolve.BindingContext;
 import org.jetbrains.jet.lang.resolve.BindingContextUtils;
 import org.jetbrains.jet.lang.resolve.BindingTrace;
-import org.jetbrains.jet.lang.resolve.calls.ResolvedCall;
 import org.jetbrains.jet.lang.types.JetStandardClasses;
 import org.jetbrains.jet.lang.types.JetType;
 import org.jetbrains.jet.lang.types.expressions.OperatorConventions;
 import org.jetbrains.jet.lexer.JetTokens;
 
-import java.util.*;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.LinkedList;
+import java.util.List;
 
 import static org.jetbrains.jet.lang.diagnostics.Errors.*;
 
@@ -356,18 +357,35 @@ public class JetControlFlowProcessor {
                 });
             }
 
-            Label onException = builder.createUnboundLabel();
-            builder.nondeterministicJump(onException);
+            List<JetCatchClause> catchClauses = expression.getCatchClauses();
+            final boolean hasCatches = !catchClauses.isEmpty();
+            Label onException = null;
+            if (hasCatches) {
+                onException = builder.createUnboundLabel();
+                builder.nondeterministicJump(onException);
+            }
             value(expression.getTryBlock(), inCondition);
 
-            List<JetCatchClause> catchClauses = expression.getCatchClauses();
-            if (!catchClauses.isEmpty()) {
+            if (hasCatches) {
+                builder.allowDead();
                 Label afterCatches = builder.createUnboundLabel();
                 builder.jump(afterCatches);
 
                 builder.bindLabel(onException);
-                for (Iterator<JetCatchClause> iterator = catchClauses.iterator(); iterator.hasNext(); ) {
-                    JetCatchClause catchClause = iterator.next();
+                LinkedList<Label> catchLabels = Lists.newLinkedList();
+                int catchClausesSize = catchClauses.size();
+                for (int i = 0; i < catchClausesSize - 1; i++) {
+                    catchLabels.add(builder.createUnboundLabel());
+                }
+                builder.nondeterministicJump(catchLabels);
+                boolean isFirst = true;
+                for (JetCatchClause catchClause : catchClauses) {
+                    if (!isFirst) {
+                        builder.bindLabel(catchLabels.remove());
+                    }
+                    else {
+                        isFirst = false;
+                    }
                     JetParameter catchParameter = catchClause.getCatchParameter();
                     if (catchParameter != null) {
                         builder.write(catchParameter, catchParameter);
@@ -376,14 +394,14 @@ public class JetControlFlowProcessor {
                     if (catchBody != null) {
                         value(catchBody, false);
                     }
-                    if (iterator.hasNext()) {
-                        builder.nondeterministicJump(afterCatches);
-                    }
+                    builder.allowDead();
+                    builder.jump(afterCatches);
                 }
 
                 builder.bindLabel(afterCatches);
-            } else {
-                builder.bindLabel(onException);
+            }
+            else {
+                builder.allowDead();
             }
 
             if (finallyBlock != null) {
diff --git a/compiler/frontend/src/org/jetbrains/jet/lang/cfg/pseudocode/JetControlFlowInstructionsGenerator.java b/compiler/frontend/src/org/jetbrains/jet/lang/cfg/pseudocode/JetControlFlowInstructionsGenerator.java
index ad12a39d3cd..9c5e14b2c58 100644
--- a/compiler/frontend/src/org/jetbrains/jet/lang/cfg/pseudocode/JetControlFlowInstructionsGenerator.java
+++ b/compiler/frontend/src/org/jetbrains/jet/lang/cfg/pseudocode/JetControlFlowInstructionsGenerator.java
@@ -243,6 +243,13 @@ public class JetControlFlowInstructionsGenerator extends JetControlFlowBuilderAd
             pseudocode.bindLabel(label);
         }
 
+        @Override
+        public void allowDead() {
+            Label allowedDeadLabel = createUnboundLabel();
+            bindLabel(allowedDeadLabel);
+            pseudocode.allowDead(allowedDeadLabel);
+        }
+
         @Override
         public void nondeterministicJump(Label label) {
             handleJumpInsideTryFinally(label);
diff --git a/compiler/frontend/src/org/jetbrains/jet/lang/cfg/pseudocode/NondeterministicJumpInstruction.java b/compiler/frontend/src/org/jetbrains/jet/lang/cfg/pseudocode/NondeterministicJumpInstruction.java
index 0e7901c4d78..f84ecb737b7 100644
--- a/compiler/frontend/src/org/jetbrains/jet/lang/cfg/pseudocode/NondeterministicJumpInstruction.java
+++ b/compiler/frontend/src/org/jetbrains/jet/lang/cfg/pseudocode/NondeterministicJumpInstruction.java
@@ -17,7 +17,7 @@ public class NondeterministicJumpInstruction extends InstructionImpl{
     private final Map<Label, Instruction> resolvedTargets;
 
     public NondeterministicJumpInstruction(List<Label> targetLabels) {
-        this.targetLabels = targetLabels;
+        this.targetLabels = Lists.newArrayList(targetLabels);
         resolvedTargets = Maps.newLinkedHashMap();
     }
 
diff --git a/compiler/frontend/src/org/jetbrains/jet/lang/cfg/pseudocode/Pseudocode.java b/compiler/frontend/src/org/jetbrains/jet/lang/cfg/pseudocode/Pseudocode.java
index 6acdefd6136..520b52437a8 100644
--- a/compiler/frontend/src/org/jetbrains/jet/lang/cfg/pseudocode/Pseudocode.java
+++ b/compiler/frontend/src/org/jetbrains/jet/lang/cfg/pseudocode/Pseudocode.java
@@ -44,18 +44,20 @@ public class Pseudocode {
         @Nullable
         private List<Instruction> resolve() {
             assert targetInstructionIndex != null;
-            return instructions.subList(getTargetInstructionIndex(), instructions.size());
+            return mutableInstructionList.subList(getTargetInstructionIndex(), mutableInstructionList.size());
         }
 
         public Instruction resolveToInstruction() {
             assert targetInstructionIndex != null;
-            return instructions.get(targetInstructionIndex);
+            return mutableInstructionList.get(targetInstructionIndex);
         }
 
     }
 
+    private final List<Instruction> mutableInstructionList = new ArrayList<Instruction>();
     private final List<Instruction> instructions = new ArrayList<Instruction>();
     private final List<PseudocodeLabel> labels = new ArrayList<PseudocodeLabel>();
+    private final List<PseudocodeLabel> allowedDeadLabels = new ArrayList<PseudocodeLabel>();
 
     private final JetElement correspondingElement;
     private SubroutineExitInstruction exitInstruction;
@@ -75,11 +77,21 @@ public class Pseudocode {
         labels.add(label);
         return label;
     }
+    
+    public void allowDead(Label label) {
+        allowedDeadLabels.add((PseudocodeLabel) label);
+    }
 
     @NotNull
     public List<Instruction> getInstructions() {
         return instructions;
     }
+
+    @Deprecated //for tests only
+    @NotNull
+    public List<Instruction> getMutableInstructionList() {
+        return mutableInstructionList;
+    }
     
     @NotNull
     public List<Instruction> getDeadInstructions() {
@@ -93,6 +105,7 @@ public class Pseudocode {
     }
 
     @Deprecated //for tests only
+    @NotNull
     public List<PseudocodeLabel> getLabels() {
         return labels;
     }
@@ -110,7 +123,7 @@ public class Pseudocode {
     }
 
     public void addInstruction(Instruction instruction) {
-        instructions.add(instruction);
+        mutableInstructionList.add(instruction);
         instruction.setOwner(this);
     }
 
@@ -127,18 +140,18 @@ public class Pseudocode {
 
     @NotNull
     public SubroutineEnterInstruction getEnterInstruction() {
-        return (SubroutineEnterInstruction) instructions.get(0);
+        return (SubroutineEnterInstruction) mutableInstructionList.get(0);
     }
 
     public void bindLabel(Label label) {
-        ((PseudocodeLabel) label).setTargetInstructionIndex(instructions.size());
+        ((PseudocodeLabel) label).setTargetInstructionIndex(mutableInstructionList.size());
     }
 
     public void postProcess() {
         if (postPrecessed) return;
         postPrecessed = true;
-        for (int i = 0, instructionsSize = instructions.size(); i < instructionsSize; i++) {
-            Instruction instruction = instructions.get(i);
+        for (int i = 0, instructionsSize = mutableInstructionList.size(); i < instructionsSize; i++) {
+            Instruction instruction = mutableInstructionList.get(i);
             final int currentPosition = i;
             instruction.accept(new InstructionVisitor() {
                 @Override
@@ -198,15 +211,20 @@ public class Pseudocode {
             });
         }
         getExitInstruction().setSink(getSinkInstruction());
-        removeDeadInstructions();
+        Set<Instruction> allowedDeadStartInstructions = prepareAllowedDeadInstructions();
+        markDeadInstructions();
+        Collection<Instruction> allowedDeadInstructions = collectAllowedDeadInstructions(allowedDeadStartInstructions);
+        instructions.addAll(mutableInstructionList);
+        instructions.removeAll(allowedDeadInstructions);
+
     }
 
-    private void removeDeadInstructions() {
+    private void markDeadInstructions() {
         boolean hasRemovedInstruction = true;
         Collection<Instruction> processedInstructions = Sets.newHashSet();
         while (hasRemovedInstruction) {
             hasRemovedInstruction = false;
-            for (Instruction instruction : instructions) {
+            for (Instruction instruction : mutableInstructionList) {
                 if (!(instruction instanceof SubroutineEnterInstruction || instruction instanceof SubroutineExitInstruction || instruction instanceof SubroutineSinkInstruction) &&
                     instruction.getPreviousInstructions().isEmpty() && !processedInstructions.contains(instruction)) {
                     hasRemovedInstruction = true;
@@ -220,6 +238,36 @@ public class Pseudocode {
         }
     }
 
+    @NotNull
+    private Set<Instruction> prepareAllowedDeadInstructions() {
+        Set<Instruction> allowedDeadStartInstructions = Sets.newHashSet();
+        for (PseudocodeLabel allowedDeadLabel : allowedDeadLabels) {
+            Instruction allowedDeadInstruction = getJumpTarget(allowedDeadLabel);
+            if (allowedDeadInstruction.getPreviousInstructions().isEmpty()) {
+                allowedDeadStartInstructions.add(allowedDeadInstruction);
+            }
+        }
+        return allowedDeadStartInstructions;
+    }
+
+    @NotNull
+    private Collection<Instruction> collectAllowedDeadInstructions(@NotNull Set<Instruction> allowedDeadStartInstructions) {
+        Set<Instruction> allowedDeadInstructions = Sets.newHashSet();
+        for (Instruction allowedDeadStartInstruction : allowedDeadStartInstructions) {
+            collectAllowedDeadInstructions(allowedDeadStartInstruction, allowedDeadInstructions);
+        }
+        return allowedDeadInstructions;
+    }
+    
+    private void collectAllowedDeadInstructions(Instruction allowedDeadInstruction, Set<Instruction> instructionSet) {
+        if (allowedDeadInstruction.isDead()) {
+            instructionSet.add(allowedDeadInstruction);
+            for (Instruction instruction : allowedDeadInstruction.getNextInstructions()) {
+                collectAllowedDeadInstructions(instruction, instructionSet);
+            }
+        }
+    }
+
     @NotNull
     private Instruction getJumpTarget(@NotNull Label targetLabel) {
         return ((PseudocodeLabel)targetLabel).resolveToInstruction();
@@ -228,7 +276,7 @@ public class Pseudocode {
     @NotNull
     private Instruction getNextPosition(int currentPosition) {
         int targetPosition = currentPosition + 1;
-        assert targetPosition < instructions.size() : currentPosition;
-        return instructions.get(targetPosition);
+        assert targetPosition < mutableInstructionList.size() : currentPosition;
+        return mutableInstructionList.get(targetPosition);
     }
 }
diff --git a/compiler/testData/cfg/Finally.instructions b/compiler/testData/cfg/Finally.instructions
index 8802a5daeaa..09dddc96174 100644
--- a/compiler/testData/cfg/Finally.instructions
+++ b/compiler/testData/cfg/Finally.instructions
@@ -8,17 +8,16 @@ fun t1() {
 }
 ---------------------
 l0:
-    <START>     NEXT:[jmp?(l2)]      PREV:[]
-    jmp?(l2)    NEXT:[r(2), r(1)]    PREV:[<START>]
-    r(1)        NEXT:[r(2)]          PREV:[jmp?(l2)]
+    <START>    NEXT:[r(1)]      PREV:[]
+    r(1)       NEXT:[r(2)]      PREV:[<START>]
 l2:
-    r(2)        NEXT:[<END>]         PREV:[jmp?(l2), r(1)]
+    r(2)       NEXT:[<END>]     PREV:[r(1)]
 l1:
-    <END>       NEXT:[<SINK>]        PREV:[r(2)]
+    <END>      NEXT:[<SINK>]    PREV:[r(2)]
 error:
-    <ERROR>     NEXT:[]              PREV:[]
+    <ERROR>    NEXT:[]          PREV:[]
 sink:
-    <SINK>      NEXT:[]              PREV:[<END>]
+    <SINK>     NEXT:[]          PREV:[<END>]
 =====================
 == t2 ==
 fun t2() {
@@ -33,22 +32,21 @@ fun t2() {
 }
 ---------------------
 l0:
-    <START>        NEXT:[jmp?(l2)]             PREV:[]
-    jmp?(l2)       NEXT:[r(2), r(1)]           PREV:[<START>]
-    r(1)           NEXT:[r(2)]                 PREV:[jmp?(l2)]
+    <START>        NEXT:[r(1)]                 PREV:[]
+    r(1)           NEXT:[r(2)]                 PREV:[<START>]
     r(2)           NEXT:[r(3)]                 PREV:[r(1)]
     r(3)           NEXT:[r(>)]                 PREV:[r(2)]
     r(>)           NEXT:[r(2 > 3)]             PREV:[r(3)]
-    r(2 > 3)       NEXT:[jf(l3)]               PREV:[r(>)]
-    jf(l3)         NEXT:[read (Unit), r(2)]    PREV:[r(2 > 3)]
-    r(2)           NEXT:[ret l1]               PREV:[jf(l3)]
+    r(2 > 3)       NEXT:[jf(l2)]               PREV:[r(>)]
+    jf(l2)         NEXT:[read (Unit), r(2)]    PREV:[r(2 > 3)]
+    r(2)           NEXT:[ret l1]               PREV:[jf(l2)]
     ret l1         NEXT:[<END>]                PREV:[r(2)]
-*   jmp(l4)        NEXT:[r(2)]                 PREV:[]
-l3:
-    read (Unit)    NEXT:[r(2)]                 PREV:[jf(l3)]
+*   jmp(l3)        NEXT:[r(2)]                 PREV:[]
 l2:
+    read (Unit)    NEXT:[r(2)]                 PREV:[jf(l2)]
+l3:
 l4:
-    r(2)           NEXT:[<END>]                PREV:[jmp?(l2), read (Unit)]
+    r(2)           NEXT:[<END>]                PREV:[read (Unit)]
 l1:
     <END>          NEXT:[<SINK>]               PREV:[ret l1, r(2)]
 error:
@@ -63,20 +61,20 @@ sink:
         }
     }
 ---------------------
-l4:
+l3:
     <START>        NEXT:[r(2)]                   PREV:[]
     r(2)           NEXT:[r(3)]                   PREV:[<START>]
     r(3)           NEXT:[r(>)]                   PREV:[r(2)]
     r(>)           NEXT:[r(2 > 3)]               PREV:[r(3)]
-    r(2 > 3)       NEXT:[jf(l6)]                 PREV:[r(>)]
-    jf(l6)         NEXT:[read (Unit), ret l5]    PREV:[r(2 > 3)]
-    ret l5         NEXT:[<END>]                  PREV:[jf(l6)]
-*   jmp(l7)        NEXT:[<END>]                  PREV:[]
-l6:
-    read (Unit)    NEXT:[<END>]                  PREV:[jf(l6)]
+    r(2 > 3)       NEXT:[jf(l5)]                 PREV:[r(>)]
+    jf(l5)         NEXT:[read (Unit), ret l4]    PREV:[r(2 > 3)]
+    ret l4         NEXT:[<END>]                  PREV:[jf(l5)]
+*   jmp(l6)        NEXT:[<END>]                  PREV:[]
 l5:
-l7:
-    <END>          NEXT:[<SINK>]                 PREV:[ret l5, read (Unit)]
+    read (Unit)    NEXT:[<END>]                  PREV:[jf(l5)]
+l4:
+l6:
+    <END>          NEXT:[<SINK>]                 PREV:[ret l4, read (Unit)]
 error:
     <ERROR>        NEXT:[]                       PREV:[]
 sink:
@@ -97,43 +95,42 @@ fun t3() {
 }
 ---------------------
 l0:
-    <START>                 NEXT:[jmp?(l2)]                                                            PREV:[]
-    jmp?(l2)                NEXT:[r(2), r(1)]                                                          PREV:[<START>]
-    r(1)                    NEXT:[jmp?(l3)]                                                            PREV:[jmp?(l2)]
-    jmp?(l3)                NEXT:[r({ () => if (2 > 3) { retur..), d({ () => if (2 > 3) { retur..)]    PREV:[r(1)]
+    <START>                 NEXT:[r(1)]                                                                PREV:[]
+    r(1)                    NEXT:[jmp?(l2)]                                                            PREV:[<START>]
+    jmp?(l2)                NEXT:[r({ () => if (2 > 3) { retur..), d({ () => if (2 > 3) { retur..)]    PREV:[r(1)]
     d({ () =>           
             if (2 > 3) {
               return@   
             }           
-        })                  NEXT:[<SINK>]                                                              PREV:[jmp?(l3)]
-l3:
+        })                  NEXT:[<SINK>]                                                              PREV:[jmp?(l2)]
+l2:
     r({ () =>           
             if (2 > 3) {
               return@   
             }           
-        })                  NEXT:[r(2)]                                                                PREV:[jmp?(l3)]
-l2:
-    r(2)                    NEXT:[<END>]                                                               PREV:[jmp?(l2), r({ () => if (2 > 3) { retur..)]
+        })                  NEXT:[r(2)]                                                                PREV:[jmp?(l2)]
+l7:
+    r(2)                    NEXT:[<END>]                                                               PREV:[r({ () => if (2 > 3) { retur..)]
 l1:
     <END>                   NEXT:[<SINK>]                                                              PREV:[r(2)]
 error:
     <ERROR>                 NEXT:[]                                                                    PREV:[]
 sink:
     <SINK>                  NEXT:[]                                                                    PREV:[d({ () => if (2 > 3) { retur..), <END>]
-l4:
+l3:
     <START>        NEXT:[r(2)]                   PREV:[]
     r(2)           NEXT:[r(3)]                   PREV:[<START>]
     r(3)           NEXT:[r(>)]                   PREV:[r(2)]
     r(>)           NEXT:[r(2 > 3)]               PREV:[r(3)]
-    r(2 > 3)       NEXT:[jf(l6)]                 PREV:[r(>)]
-    jf(l6)         NEXT:[read (Unit), ret l5]    PREV:[r(2 > 3)]
-    ret l5         NEXT:[<END>]                  PREV:[jf(l6)]
-*   jmp(l7)        NEXT:[<END>]                  PREV:[]
-l6:
-    read (Unit)    NEXT:[<END>]                  PREV:[jf(l6)]
+    r(2 > 3)       NEXT:[jf(l5)]                 PREV:[r(>)]
+    jf(l5)         NEXT:[read (Unit), ret l4]    PREV:[r(2 > 3)]
+    ret l4         NEXT:[<END>]                  PREV:[jf(l5)]
+*   jmp(l6)        NEXT:[<END>]                  PREV:[]
 l5:
-l7:
-    <END>          NEXT:[<SINK>]                 PREV:[ret l5, read (Unit)]
+    read (Unit)    NEXT:[<END>]                  PREV:[jf(l5)]
+l4:
+l6:
+    <END>          NEXT:[<SINK>]                 PREV:[ret l4, read (Unit)]
 error:
     <ERROR>        NEXT:[]                       PREV:[]
 sink:
@@ -152,22 +149,21 @@ sink:
   }
 ---------------------
 l3:
-    <START>        NEXT:[jmp?(l5)]             PREV:[]
-    jmp?(l5)       NEXT:[r(2), r(1)]           PREV:[<START>]
-    r(1)           NEXT:[r(2)]                 PREV:[jmp?(l5)]
+    <START>        NEXT:[r(1)]                 PREV:[]
+    r(1)           NEXT:[r(2)]                 PREV:[<START>]
     r(2)           NEXT:[r(3)]                 PREV:[r(1)]
     r(3)           NEXT:[r(>)]                 PREV:[r(2)]
     r(>)           NEXT:[r(2 > 3)]             PREV:[r(3)]
-    r(2 > 3)       NEXT:[jf(l6)]               PREV:[r(>)]
-    jf(l6)         NEXT:[read (Unit), r(2)]    PREV:[r(2 > 3)]
-    r(2)           NEXT:[ret l4]               PREV:[jf(l6)]
+    r(2 > 3)       NEXT:[jf(l5)]               PREV:[r(>)]
+    jf(l5)         NEXT:[read (Unit), r(2)]    PREV:[r(2 > 3)]
+    r(2)           NEXT:[ret l4]               PREV:[jf(l5)]
     ret l4         NEXT:[<END>]                PREV:[r(2)]
-*   jmp(l7)        NEXT:[r(2)]                 PREV:[]
-l6:
-    read (Unit)    NEXT:[r(2)]                 PREV:[jf(l6)]
+*   jmp(l6)        NEXT:[r(2)]                 PREV:[]
 l5:
+    read (Unit)    NEXT:[r(2)]                 PREV:[jf(l5)]
+l6:
 l7:
-    r(2)           NEXT:[<END>]                PREV:[jmp?(l5), read (Unit)]
+    r(2)           NEXT:[<END>]                PREV:[read (Unit)]
 l4:
     <END>          NEXT:[<SINK>]               PREV:[ret l4, r(2)]
 error:
@@ -220,22 +216,21 @@ error:
 sink:
     <SINK>                NEXT:[]                                                                    PREV:[d({ () => try { 1 if (2 > 3)..), <END>]
 l3:
-    <START>        NEXT:[jmp?(l5)]             PREV:[]
-    jmp?(l5)       NEXT:[r(2), r(1)]           PREV:[<START>]
-    r(1)           NEXT:[r(2)]                 PREV:[jmp?(l5)]
+    <START>        NEXT:[r(1)]                 PREV:[]
+    r(1)           NEXT:[r(2)]                 PREV:[<START>]
     r(2)           NEXT:[r(3)]                 PREV:[r(1)]
     r(3)           NEXT:[r(>)]                 PREV:[r(2)]
     r(>)           NEXT:[r(2 > 3)]             PREV:[r(3)]
-    r(2 > 3)       NEXT:[jf(l6)]               PREV:[r(>)]
-    jf(l6)         NEXT:[read (Unit), r(2)]    PREV:[r(2 > 3)]
-    r(2)           NEXT:[ret l4]               PREV:[jf(l6)]
+    r(2 > 3)       NEXT:[jf(l5)]               PREV:[r(>)]
+    jf(l5)         NEXT:[read (Unit), r(2)]    PREV:[r(2 > 3)]
+    r(2)           NEXT:[ret l4]               PREV:[jf(l5)]
     ret l4         NEXT:[<END>]                PREV:[r(2)]
-*   jmp(l7)        NEXT:[r(2)]                 PREV:[]
-l6:
-    read (Unit)    NEXT:[r(2)]                 PREV:[jf(l6)]
+*   jmp(l6)        NEXT:[r(2)]                 PREV:[]
 l5:
+    read (Unit)    NEXT:[r(2)]                 PREV:[jf(l5)]
+l6:
 l7:
-    r(2)           NEXT:[<END>]                PREV:[jmp?(l5), read (Unit)]
+    r(2)           NEXT:[<END>]                PREV:[read (Unit)]
 l4:
     <END>          NEXT:[<SINK>]               PREV:[ret l4, r(2)]
 error:
@@ -258,36 +253,35 @@ fun t5() {
 }
 ---------------------
 l0:
-    <START>        NEXT:[r(true)]                  PREV:[]
+    <START>        NEXT:[r(true)]              PREV:[]
 l2:
 l5:
-    r(true)        NEXT:[jf(l3)]                   PREV:[<START>, jmp(l2)]
-    jf(l3)         NEXT:[read (Unit), jmp?(l6)]    PREV:[r(true)]
+    r(true)        NEXT:[jf(l3)]               PREV:[<START>, jmp(l2)]
+    jf(l3)         NEXT:[read (Unit), r(1)]    PREV:[r(true)]
 l4:
-    jmp?(l6)       NEXT:[r(2), r(1)]               PREV:[jf(l3)]
-    r(1)           NEXT:[r(2)]                     PREV:[jmp?(l6)]
-    r(2)           NEXT:[r(3)]                     PREV:[r(1)]
-    r(3)           NEXT:[r(>)]                     PREV:[r(2)]
-    r(>)           NEXT:[r(2 > 3)]                 PREV:[r(3)]
-    r(2 > 3)       NEXT:[jf(l7)]                   PREV:[r(>)]
-    jf(l7)         NEXT:[read (Unit), r(2)]        PREV:[r(2 > 3)]
-    r(2)           NEXT:[jmp(l3)]                  PREV:[jf(l7)]
-    jmp(l3)        NEXT:[read (Unit)]              PREV:[r(2)]
-*   jmp(l8)        NEXT:[r(2)]                     PREV:[]
-l7:
-    read (Unit)    NEXT:[r(2)]                     PREV:[jf(l7)]
+    r(1)           NEXT:[r(2)]                 PREV:[jf(l3)]
+    r(2)           NEXT:[r(3)]                 PREV:[r(1)]
+    r(3)           NEXT:[r(>)]                 PREV:[r(2)]
+    r(>)           NEXT:[r(2 > 3)]             PREV:[r(3)]
+    r(2 > 3)       NEXT:[jf(l6)]               PREV:[r(>)]
+    jf(l6)         NEXT:[read (Unit), r(2)]    PREV:[r(2 > 3)]
+    r(2)           NEXT:[jmp(l3)]              PREV:[jf(l6)]
+    jmp(l3)        NEXT:[read (Unit)]          PREV:[r(2)]
+*   jmp(l7)        NEXT:[r(2)]                 PREV:[]
 l6:
+    read (Unit)    NEXT:[r(2)]                 PREV:[jf(l6)]
+l7:
 l8:
-    r(2)           NEXT:[jmp(l2)]                  PREV:[jmp?(l6), read (Unit)]
-    jmp(l2)        NEXT:[r(true)]                  PREV:[r(2)]
+    r(2)           NEXT:[jmp(l2)]              PREV:[read (Unit)]
+    jmp(l2)        NEXT:[r(true)]              PREV:[r(2)]
 l3:
-    read (Unit)    NEXT:[<END>]                    PREV:[jf(l3), jmp(l3)]
+    read (Unit)    NEXT:[<END>]                PREV:[jf(l3), jmp(l3)]
 l1:
-    <END>          NEXT:[<SINK>]                   PREV:[read (Unit)]
+    <END>          NEXT:[<SINK>]               PREV:[read (Unit)]
 error:
-    <ERROR>        NEXT:[]                         PREV:[]
+    <ERROR>        NEXT:[]                     PREV:[]
 sink:
-    <SINK>         NEXT:[]                         PREV:[<END>]
+    <SINK>         NEXT:[]                     PREV:[<END>]
 =====================
 == t6 ==
 fun t6() {
@@ -305,30 +299,29 @@ fun t6() {
 }
 ---------------------
 l0:
-    <START>        NEXT:[jmp?(l2)]                PREV:[]
-    jmp?(l2)       NEXT:[r(2), r(true)]           PREV:[<START>]
-l3:
-l6:
-    r(true)        NEXT:[jf(l4)]                  PREV:[jmp?(l2), jmp(l3)]
-    jf(l4)         NEXT:[read (Unit), r(1)]       PREV:[r(true)]
+    <START>        NEXT:[r(true)]                 PREV:[]
+l2:
 l5:
-    r(1)           NEXT:[r(2)]                    PREV:[jf(l4)]
+    r(true)        NEXT:[jf(l3)]                  PREV:[<START>, jmp(l2)]
+    jf(l3)         NEXT:[read (Unit), r(1)]       PREV:[r(true)]
+l4:
+    r(1)           NEXT:[r(2)]                    PREV:[jf(l3)]
     r(2)           NEXT:[r(3)]                    PREV:[r(1)]
     r(3)           NEXT:[r(>)]                    PREV:[r(2)]
     r(>)           NEXT:[r(2 > 3)]                PREV:[r(3)]
-    r(2 > 3)       NEXT:[jf(l7)]                  PREV:[r(>)]
-    jf(l7)         NEXT:[read (Unit), jmp(l4)]    PREV:[r(2 > 3)]
-    jmp(l4)        NEXT:[read (Unit)]             PREV:[jf(l7)]
-*   jmp(l8)        NEXT:[jmp(l3)]                 PREV:[]
+    r(2 > 3)       NEXT:[jf(l6)]                  PREV:[r(>)]
+    jf(l6)         NEXT:[read (Unit), jmp(l3)]    PREV:[r(2 > 3)]
+    jmp(l3)        NEXT:[read (Unit)]             PREV:[jf(l6)]
+*   jmp(l7)        NEXT:[jmp(l2)]                 PREV:[]
+l6:
+    read (Unit)    NEXT:[jmp(l2)]                 PREV:[jf(l6)]
 l7:
-    read (Unit)    NEXT:[jmp(l3)]                 PREV:[jf(l7)]
-l8:
-    jmp(l3)        NEXT:[r(true)]                 PREV:[read (Unit)]
-l4:
-    read (Unit)    NEXT:[r(5)]                    PREV:[jf(l4), jmp(l4)]
+    jmp(l2)        NEXT:[r(true)]                 PREV:[read (Unit)]
+l3:
+    read (Unit)    NEXT:[r(5)]                    PREV:[jf(l3), jmp(l3)]
     r(5)           NEXT:[r(2)]                    PREV:[read (Unit)]
-l2:
-    r(2)           NEXT:[<END>]                   PREV:[jmp?(l2), r(5)]
+l8:
+    r(2)           NEXT:[<END>]                   PREV:[r(5)]
 l1:
     <END>          NEXT:[<SINK>]                  PREV:[r(2)]
 error:
@@ -351,29 +344,28 @@ fun t7() {
 }
 ---------------------
 l0:
-    <START>        NEXT:[jmp?(l2)]                PREV:[]
-    jmp?(l2)       NEXT:[r(2), r(true)]           PREV:[<START>]
-l3:
-l6:
-    r(true)        NEXT:[jf(l4)]                  PREV:[jmp?(l2), jmp(l3)]
-    jf(l4)         NEXT:[read (Unit), r(1)]       PREV:[r(true)]
+    <START>        NEXT:[r(true)]                 PREV:[]
+l2:
 l5:
-    r(1)           NEXT:[r(2)]                    PREV:[jf(l4)]
+    r(true)        NEXT:[jf(l3)]                  PREV:[<START>, jmp(l2)]
+    jf(l3)         NEXT:[read (Unit), r(1)]       PREV:[r(true)]
+l4:
+    r(1)           NEXT:[r(2)]                    PREV:[jf(l3)]
     r(2)           NEXT:[r(3)]                    PREV:[r(1)]
     r(3)           NEXT:[r(>)]                    PREV:[r(2)]
     r(>)           NEXT:[r(2 > 3)]                PREV:[r(3)]
-    r(2 > 3)       NEXT:[jf(l7)]                  PREV:[r(>)]
-    jf(l7)         NEXT:[read (Unit), jmp(l4)]    PREV:[r(2 > 3)]
-    jmp(l4)        NEXT:[read (Unit)]             PREV:[jf(l7)]
-*   jmp(l8)        NEXT:[jmp(l3)]                 PREV:[]
+    r(2 > 3)       NEXT:[jf(l6)]                  PREV:[r(>)]
+    jf(l6)         NEXT:[read (Unit), jmp(l3)]    PREV:[r(2 > 3)]
+    jmp(l3)        NEXT:[read (Unit)]             PREV:[jf(l6)]
+*   jmp(l7)        NEXT:[jmp(l2)]                 PREV:[]
+l6:
+    read (Unit)    NEXT:[jmp(l2)]                 PREV:[jf(l6)]
 l7:
-    read (Unit)    NEXT:[jmp(l3)]                 PREV:[jf(l7)]
+    jmp(l2)        NEXT:[r(true)]                 PREV:[read (Unit)]
+l3:
+    read (Unit)    NEXT:[r(2)]                    PREV:[jf(l3), jmp(l3)]
 l8:
-    jmp(l3)        NEXT:[r(true)]                 PREV:[read (Unit)]
-l4:
-    read (Unit)    NEXT:[r(2)]                    PREV:[jf(l4), jmp(l4)]
-l2:
-    r(2)           NEXT:[<END>]                   PREV:[jmp?(l2), read (Unit)]
+    r(2)           NEXT:[<END>]                   PREV:[read (Unit)]
 l1:
     <END>          NEXT:[<SINK>]                  PREV:[r(2)]
 error:
@@ -396,40 +388,39 @@ fun t8(a : Int) {
 }
 ---------------------
 l0:
-    <START>        NEXT:[r(1)]                     PREV:[]
-    r(1)           NEXT:[r(a)]                     PREV:[<START>]
-    r(a)           NEXT:[r(..)]                    PREV:[r(1)]
-    r(..)          NEXT:[r(1..a)]                  PREV:[r(a)]
-    r(1..a)        NEXT:[w(i)]                     PREV:[r(..)]
-    w(i)           NEXT:[jmp?(l2)]                 PREV:[r(1..a)]
+    <START>        NEXT:[r(1)]                 PREV:[]
+    r(1)           NEXT:[r(a)]                 PREV:[<START>]
+    r(a)           NEXT:[r(..)]                PREV:[r(1)]
+    r(..)          NEXT:[r(1..a)]              PREV:[r(a)]
+    r(1..a)        NEXT:[w(i)]                 PREV:[r(..)]
+    w(i)           NEXT:[jmp?(l2)]             PREV:[r(1..a)]
 l3:
-    jmp?(l2)       NEXT:[read (Unit), jmp?(l6)]    PREV:[w(i)]
+    jmp?(l2)       NEXT:[read (Unit), r(1)]    PREV:[w(i)]
 l4:
 l5:
-    jmp?(l6)       NEXT:[r(2), r(1)]               PREV:[jmp?(l2), jmp(l4), jmp?(l4)]
-    r(1)           NEXT:[r(2)]                     PREV:[jmp?(l6)]
-    r(2)           NEXT:[r(3)]                     PREV:[r(1)]
-    r(3)           NEXT:[r(>)]                     PREV:[r(2)]
-    r(>)           NEXT:[r(2 > 3)]                 PREV:[r(3)]
-    r(2 > 3)       NEXT:[jf(l7)]                   PREV:[r(>)]
-    jf(l7)         NEXT:[read (Unit), r(2)]        PREV:[r(2 > 3)]
-    r(2)           NEXT:[jmp(l4)]                  PREV:[jf(l7)]
-    jmp(l4)        NEXT:[jmp?(l6)]                 PREV:[r(2)]
-*   jmp(l8)        NEXT:[r(2)]                     PREV:[]
-l7:
-    read (Unit)    NEXT:[r(2)]                     PREV:[jf(l7)]
+    r(1)           NEXT:[r(2)]                 PREV:[jmp?(l2), jmp(l4), jmp?(l4)]
+    r(2)           NEXT:[r(3)]                 PREV:[r(1)]
+    r(3)           NEXT:[r(>)]                 PREV:[r(2)]
+    r(>)           NEXT:[r(2 > 3)]             PREV:[r(3)]
+    r(2 > 3)       NEXT:[jf(l6)]               PREV:[r(>)]
+    jf(l6)         NEXT:[read (Unit), r(2)]    PREV:[r(2 > 3)]
+    r(2)           NEXT:[jmp(l4)]              PREV:[jf(l6)]
+    jmp(l4)        NEXT:[r(1)]                 PREV:[r(2)]
+*   jmp(l7)        NEXT:[r(2)]                 PREV:[]
 l6:
+    read (Unit)    NEXT:[r(2)]                 PREV:[jf(l6)]
+l7:
 l8:
-    r(2)           NEXT:[jmp?(l4)]                 PREV:[jmp?(l6), read (Unit)]
-    jmp?(l4)       NEXT:[jmp?(l6), read (Unit)]    PREV:[r(2)]
+    r(2)           NEXT:[jmp?(l4)]             PREV:[read (Unit)]
+    jmp?(l4)       NEXT:[r(1), read (Unit)]    PREV:[r(2)]
 l2:
-    read (Unit)    NEXT:[<END>]                    PREV:[jmp?(l2), jmp?(l4)]
+    read (Unit)    NEXT:[<END>]                PREV:[jmp?(l2), jmp?(l4)]
 l1:
-    <END>          NEXT:[<SINK>]                   PREV:[read (Unit)]
+    <END>          NEXT:[<SINK>]               PREV:[read (Unit)]
 error:
-    <ERROR>        NEXT:[]                         PREV:[]
+    <ERROR>        NEXT:[]                     PREV:[]
 sink:
-    <SINK>         NEXT:[]                         PREV:[<END>]
+    <SINK>         NEXT:[]                     PREV:[<END>]
 =====================
 == t9 ==
 fun t9(a : Int) {
@@ -447,34 +438,33 @@ fun t9(a : Int) {
 }
 ---------------------
 l0:
-    <START>        NEXT:[jmp?(l2)]                PREV:[]
-    jmp?(l2)       NEXT:[r(2), r(1)]              PREV:[<START>]
-    r(1)           NEXT:[r(a)]                    PREV:[jmp?(l2)]
+    <START>        NEXT:[r(1)]                    PREV:[]
+    r(1)           NEXT:[r(a)]                    PREV:[<START>]
     r(a)           NEXT:[r(..)]                   PREV:[r(1)]
     r(..)          NEXT:[r(1..a)]                 PREV:[r(a)]
     r(1..a)        NEXT:[w(i)]                    PREV:[r(..)]
-    w(i)           NEXT:[jmp?(l3)]                PREV:[r(1..a)]
+    w(i)           NEXT:[jmp?(l2)]                PREV:[r(1..a)]
+l3:
+    jmp?(l2)       NEXT:[read (Unit), r(1)]       PREV:[w(i)]
 l4:
-    jmp?(l3)       NEXT:[read (Unit), r(1)]       PREV:[w(i)]
 l5:
-l6:
-    r(1)           NEXT:[r(2)]                    PREV:[jmp?(l3), jmp(l5), jmp?(l5)]
+    r(1)           NEXT:[r(2)]                    PREV:[jmp?(l2), jmp(l4), jmp?(l4)]
     r(2)           NEXT:[r(3)]                    PREV:[r(1)]
     r(3)           NEXT:[r(>)]                    PREV:[r(2)]
     r(>)           NEXT:[r(2 > 3)]                PREV:[r(3)]
-    r(2 > 3)       NEXT:[jf(l7)]                  PREV:[r(>)]
-    jf(l7)         NEXT:[read (Unit), jmp(l5)]    PREV:[r(2 > 3)]
-    jmp(l5)        NEXT:[r(1)]                    PREV:[jf(l7)]
-*   jmp(l8)        NEXT:[jmp?(l5)]                PREV:[]
+    r(2 > 3)       NEXT:[jf(l6)]                  PREV:[r(>)]
+    jf(l6)         NEXT:[read (Unit), jmp(l4)]    PREV:[r(2 > 3)]
+    jmp(l4)        NEXT:[r(1)]                    PREV:[jf(l6)]
+*   jmp(l7)        NEXT:[jmp?(l4)]                PREV:[]
+l6:
+    read (Unit)    NEXT:[jmp?(l4)]                PREV:[jf(l6)]
 l7:
-    read (Unit)    NEXT:[jmp?(l5)]                PREV:[jf(l7)]
-l8:
-    jmp?(l5)       NEXT:[r(1), read (Unit)]       PREV:[read (Unit)]
-l3:
-    read (Unit)    NEXT:[r(5)]                    PREV:[jmp?(l3), jmp?(l5)]
-    r(5)           NEXT:[r(2)]                    PREV:[read (Unit)]
+    jmp?(l4)       NEXT:[r(1), read (Unit)]       PREV:[read (Unit)]
 l2:
-    r(2)           NEXT:[<END>]                   PREV:[jmp?(l2), r(5)]
+    read (Unit)    NEXT:[r(5)]                    PREV:[jmp?(l2), jmp?(l4)]
+    r(5)           NEXT:[r(2)]                    PREV:[read (Unit)]
+l8:
+    r(2)           NEXT:[<END>]                   PREV:[r(5)]
 l1:
     <END>          NEXT:[<SINK>]                  PREV:[r(2)]
 error:
@@ -497,33 +487,32 @@ fun t10(a : Int) {
 }
 ---------------------
 l0:
-    <START>        NEXT:[jmp?(l2)]                PREV:[]
-    jmp?(l2)       NEXT:[r(2), r(1)]              PREV:[<START>]
-    r(1)           NEXT:[r(a)]                    PREV:[jmp?(l2)]
+    <START>        NEXT:[r(1)]                    PREV:[]
+    r(1)           NEXT:[r(a)]                    PREV:[<START>]
     r(a)           NEXT:[r(..)]                   PREV:[r(1)]
     r(..)          NEXT:[r(1..a)]                 PREV:[r(a)]
     r(1..a)        NEXT:[w(i)]                    PREV:[r(..)]
-    w(i)           NEXT:[jmp?(l3)]                PREV:[r(1..a)]
+    w(i)           NEXT:[jmp?(l2)]                PREV:[r(1..a)]
+l3:
+    jmp?(l2)       NEXT:[read (Unit), r(1)]       PREV:[w(i)]
 l4:
-    jmp?(l3)       NEXT:[read (Unit), r(1)]       PREV:[w(i)]
 l5:
-l6:
-    r(1)           NEXT:[r(2)]                    PREV:[jmp?(l3), jmp(l5), jmp?(l5)]
+    r(1)           NEXT:[r(2)]                    PREV:[jmp?(l2), jmp(l4), jmp?(l4)]
     r(2)           NEXT:[r(3)]                    PREV:[r(1)]
     r(3)           NEXT:[r(>)]                    PREV:[r(2)]
     r(>)           NEXT:[r(2 > 3)]                PREV:[r(3)]
-    r(2 > 3)       NEXT:[jf(l7)]                  PREV:[r(>)]
-    jf(l7)         NEXT:[read (Unit), jmp(l5)]    PREV:[r(2 > 3)]
-    jmp(l5)        NEXT:[r(1)]                    PREV:[jf(l7)]
-*   jmp(l8)        NEXT:[jmp?(l5)]                PREV:[]
+    r(2 > 3)       NEXT:[jf(l6)]                  PREV:[r(>)]
+    jf(l6)         NEXT:[read (Unit), jmp(l4)]    PREV:[r(2 > 3)]
+    jmp(l4)        NEXT:[r(1)]                    PREV:[jf(l6)]
+*   jmp(l7)        NEXT:[jmp?(l4)]                PREV:[]
+l6:
+    read (Unit)    NEXT:[jmp?(l4)]                PREV:[jf(l6)]
 l7:
-    read (Unit)    NEXT:[jmp?(l5)]                PREV:[jf(l7)]
-l8:
-    jmp?(l5)       NEXT:[r(1), read (Unit)]       PREV:[read (Unit)]
-l3:
-    read (Unit)    NEXT:[r(2)]                    PREV:[jmp?(l3), jmp?(l5)]
+    jmp?(l4)       NEXT:[r(1), read (Unit)]       PREV:[read (Unit)]
 l2:
-    r(2)           NEXT:[<END>]                   PREV:[jmp?(l2), read (Unit)]
+    read (Unit)    NEXT:[r(2)]                    PREV:[jmp?(l2), jmp?(l4)]
+l8:
+    r(2)           NEXT:[<END>]                   PREV:[read (Unit)]
 l1:
     <END>          NEXT:[<SINK>]                  PREV:[r(2)]
 error:
@@ -542,19 +531,221 @@ fun t11() {
 }
 ---------------------
 l0:
-    <START>      NEXT:[jmp?(l2)]      PREV:[]
-    jmp?(l2)     NEXT:[r(2), r(1)]    PREV:[<START>]
-    r(1)         NEXT:[r(2)]          PREV:[jmp?(l2)]
-    r(2)         NEXT:[ret(*) l1]     PREV:[r(1)]
-    ret(*) l1    NEXT:[<END>]         PREV:[r(2)]
-*   ret(*) l1    NEXT:[<END>]         PREV:[]
+    <START>      NEXT:[r(1)]         PREV:[]
+    r(1)         NEXT:[r(2)]         PREV:[<START>]
+    r(2)         NEXT:[ret(*) l1]    PREV:[r(1)]
+    ret(*) l1    NEXT:[<END>]        PREV:[r(2)]
+*   ret(*) l1    NEXT:[<END>]        PREV:[]
 l2:
-    r(2)         NEXT:[ret(*) l1]     PREV:[jmp?(l2)]
-    ret(*) l1    NEXT:[<END>]         PREV:[r(2)]
+R   r(2)         NEXT:[ret(*) l1]    PREV:[]
+R   ret(*) l1    NEXT:[<END>]        PREV:[]
 l1:
-    <END>        NEXT:[<SINK>]        PREV:[ret(*) l1, ret(*) l1]
+    <END>        NEXT:[<SINK>]       PREV:[ret(*) l1]
 error:
-    <ERROR>      NEXT:[]              PREV:[]
+    <ERROR>      NEXT:[]             PREV:[]
 sink:
-    <SINK>       NEXT:[]              PREV:[<END>]
+    <SINK>       NEXT:[]             PREV:[<END>]
+=====================
+== t12 ==
+fun t12() : Int {
+    try {
+        return 1
+    }
+    finally {
+        doSmth(3)
+    }
+}
+---------------------
+l0:
+    <START>         NEXT:[r(1)]            PREV:[]
+    r(1)            NEXT:[r(3)]            PREV:[<START>]
+    r(3)            NEXT:[r(doSmth)]       PREV:[r(1)]
+    r(doSmth)       NEXT:[r(doSmth(3))]    PREV:[r(3)]
+    r(doSmth(3))    NEXT:[ret(*) l1]       PREV:[r(doSmth)]
+    ret(*) l1       NEXT:[<END>]           PREV:[r(doSmth(3))]
+l2:
+R   r(3)            NEXT:[r(doSmth)]       PREV:[]
+R   r(doSmth)       NEXT:[r(doSmth(3))]    PREV:[]
+R   r(doSmth(3))    NEXT:[<END>]           PREV:[]
+l1:
+    <END>           NEXT:[<SINK>]          PREV:[ret(*) l1]
+error:
+    <ERROR>         NEXT:[]                PREV:[]
+sink:
+    <SINK>          NEXT:[]                PREV:[<END>]
+=====================
+== t13 ==
+fun t13() : Int {
+    try {
+        return 1
+    }
+    catch (e: UnsupportedOperationException) {
+        doSmth(2)
+    }
+    finally {
+        doSmth(3)
+    }
+}
+---------------------
+l0:
+    <START>         NEXT:[jmp?(l2)]        PREV:[]
+    jmp?(l2)        NEXT:[jmp?(), r(1)]    PREV:[<START>]
+    r(1)            NEXT:[r(3)]            PREV:[jmp?(l2)]
+    r(3)            NEXT:[r(doSmth)]       PREV:[r(1)]
+    r(doSmth)       NEXT:[r(doSmth(3))]    PREV:[r(3)]
+    r(doSmth(3))    NEXT:[ret(*) l1]       PREV:[r(doSmth)]
+    ret(*) l1       NEXT:[<END>]           PREV:[r(doSmth(3))]
+l3:
+R   jmp(l4)         NEXT:[r(3)]            PREV:[]
+l2:
+    jmp?()          NEXT:[w(e)]            PREV:[jmp?(l2)]
+    w(e)            NEXT:[r(2)]            PREV:[jmp?()]
+    r(2)            NEXT:[r(doSmth)]       PREV:[w(e)]
+    r(doSmth)       NEXT:[r(doSmth(2))]    PREV:[r(2)]
+    r(doSmth(2))    NEXT:[jmp(l4)]         PREV:[r(doSmth)]
+l5:
+    jmp(l4)         NEXT:[r(3)]            PREV:[r(doSmth(2))]
+l4:
+    r(3)            NEXT:[r(doSmth)]       PREV:[jmp(l4)]
+    r(doSmth)       NEXT:[r(doSmth(3))]    PREV:[r(3)]
+    r(doSmth(3))    NEXT:[<END>]           PREV:[r(doSmth)]
+l1:
+    <END>           NEXT:[<SINK>]          PREV:[ret(*) l1, r(doSmth(3))]
+error:
+    <ERROR>         NEXT:[]                PREV:[]
+sink:
+    <SINK>          NEXT:[]                PREV:[<END>]
+=====================
+== t14 ==
+fun t14() : Int {
+    try {
+        return 1
+    }
+    catch (e: UnsupportedOperationException) {
+        doSmth(2)
+    }
+}
+---------------------
+l0:
+    <START>         NEXT:[jmp?(l2)]        PREV:[]
+    jmp?(l2)        NEXT:[jmp?(), r(1)]    PREV:[<START>]
+    r(1)            NEXT:[ret(*) l1]       PREV:[jmp?(l2)]
+    ret(*) l1       NEXT:[<END>]           PREV:[r(1)]
+l3:
+R   jmp(l4)         NEXT:[<END>]           PREV:[]
+l2:
+    jmp?()          NEXT:[w(e)]            PREV:[jmp?(l2)]
+    w(e)            NEXT:[r(2)]            PREV:[jmp?()]
+    r(2)            NEXT:[r(doSmth)]       PREV:[w(e)]
+    r(doSmth)       NEXT:[r(doSmth(2))]    PREV:[r(2)]
+    r(doSmth(2))    NEXT:[jmp(l4)]         PREV:[r(doSmth)]
+l5:
+    jmp(l4)         NEXT:[<END>]           PREV:[r(doSmth(2))]
+l1:
+l4:
+    <END>           NEXT:[<SINK>]          PREV:[ret(*) l1, jmp(l4)]
+error:
+    <ERROR>         NEXT:[]                PREV:[]
+sink:
+    <SINK>          NEXT:[]                PREV:[<END>]
+=====================
+== t15 ==
+fun t15() : Int {
+    try {
+        return 1
+    }
+    catch (e: UnsupportedOperationException) {
+        return 2
+    }
+    finally {
+        doSmth(3)
+    }
+}
+---------------------
+l0:
+    <START>         NEXT:[jmp?(l2)]        PREV:[]
+    jmp?(l2)        NEXT:[jmp?(), r(1)]    PREV:[<START>]
+    r(1)            NEXT:[r(3)]            PREV:[jmp?(l2)]
+    r(3)            NEXT:[r(doSmth)]       PREV:[r(1)]
+    r(doSmth)       NEXT:[r(doSmth(3))]    PREV:[r(3)]
+    r(doSmth(3))    NEXT:[ret(*) l1]       PREV:[r(doSmth)]
+    ret(*) l1       NEXT:[<END>]           PREV:[r(doSmth(3))]
+l3:
+R   jmp(l4)         NEXT:[r(3)]            PREV:[]
+l2:
+    jmp?()          NEXT:[w(e)]            PREV:[jmp?(l2)]
+    w(e)            NEXT:[r(2)]            PREV:[jmp?()]
+    r(2)            NEXT:[r(3)]            PREV:[w(e)]
+    r(3)            NEXT:[r(doSmth)]       PREV:[r(2)]
+    r(doSmth)       NEXT:[r(doSmth(3))]    PREV:[r(3)]
+    r(doSmth(3))    NEXT:[ret(*) l1]       PREV:[r(doSmth)]
+    ret(*) l1       NEXT:[<END>]           PREV:[r(doSmth(3))]
+l5:
+R   jmp(l4)         NEXT:[r(3)]            PREV:[]
+l4:
+R   r(3)            NEXT:[r(doSmth)]       PREV:[]
+R   r(doSmth)       NEXT:[r(doSmth(3))]    PREV:[]
+R   r(doSmth(3))    NEXT:[<END>]           PREV:[]
+l1:
+    <END>           NEXT:[<SINK>]          PREV:[ret(*) l1, ret(*) l1]
+error:
+    <ERROR>         NEXT:[]                PREV:[]
+sink:
+    <SINK>          NEXT:[]                PREV:[<END>]
+=====================
+== t16 ==
+fun t16() : Int {
+    try {
+        doSmth(1)
+    }
+    catch (e: UnsupportedOperationException) {
+        return 2
+    }
+    finally {
+        doSmth(3)
+    }
+}
+---------------------
+l0:
+    <START>         NEXT:[jmp?(l2)]        PREV:[]
+    jmp?(l2)        NEXT:[jmp?(), r(1)]    PREV:[<START>]
+    r(1)            NEXT:[r(doSmth)]       PREV:[jmp?(l2)]
+    r(doSmth)       NEXT:[r(doSmth(1))]    PREV:[r(1)]
+    r(doSmth(1))    NEXT:[jmp(l4)]         PREV:[r(doSmth)]
+l3:
+    jmp(l4)         NEXT:[r(3)]            PREV:[r(doSmth(1))]
+l2:
+    jmp?()          NEXT:[w(e)]            PREV:[jmp?(l2)]
+    w(e)            NEXT:[r(2)]            PREV:[jmp?()]
+    r(2)            NEXT:[r(3)]            PREV:[w(e)]
+    r(3)            NEXT:[r(doSmth)]       PREV:[r(2)]
+    r(doSmth)       NEXT:[r(doSmth(3))]    PREV:[r(3)]
+    r(doSmth(3))    NEXT:[ret(*) l1]       PREV:[r(doSmth)]
+    ret(*) l1       NEXT:[<END>]           PREV:[r(doSmth(3))]
+l5:
+R   jmp(l4)         NEXT:[r(3)]            PREV:[]
+l4:
+    r(3)            NEXT:[r(doSmth)]       PREV:[jmp(l4)]
+    r(doSmth)       NEXT:[r(doSmth(3))]    PREV:[r(3)]
+    r(doSmth(3))    NEXT:[<END>]           PREV:[r(doSmth)]
+l1:
+    <END>           NEXT:[<SINK>]          PREV:[ret(*) l1, r(doSmth(3))]
+error:
+    <ERROR>         NEXT:[]                PREV:[]
+sink:
+    <SINK>          NEXT:[]                PREV:[<END>]
+=====================
+== doSmth ==
+fun doSmth(i: Int) {
+}
+---------------------
+l0:
+    <START>        NEXT:[read (Unit)]    PREV:[]
+    read (Unit)    NEXT:[<END>]          PREV:[<START>]
+l1:
+    <END>          NEXT:[<SINK>]         PREV:[read (Unit)]
+error:
+    <ERROR>        NEXT:[]               PREV:[]
+sink:
+    <SINK>         NEXT:[]               PREV:[<END>]
 =====================
diff --git a/compiler/testData/cfg/Finally.jet b/compiler/testData/cfg/Finally.jet
index e5cea4cfa57..71d2bc6c33f 100644
--- a/compiler/testData/cfg/Finally.jet
+++ b/compiler/testData/cfg/Finally.jet
@@ -130,4 +130,62 @@ fun t11() {
   finally {
     return 2
   }
+}
+
+fun t12() : Int {
+    try {
+        return 1
+    }
+    finally {
+        doSmth(3)
+    }
+}
+
+fun t13() : Int {
+    try {
+        return 1
+    }
+    catch (e: UnsupportedOperationException) {
+        doSmth(2)
+    }
+    finally {
+        doSmth(3)
+    }
+}
+
+fun t14() : Int {
+    try {
+        return 1
+    }
+    catch (e: UnsupportedOperationException) {
+        doSmth(2)
+    }
+}
+
+
+fun t15() : Int {
+    try {
+        return 1
+    }
+    catch (e: UnsupportedOperationException) {
+        return 2
+    }
+    finally {
+        doSmth(3)
+    }
+}
+
+fun t16() : Int {
+    try {
+        doSmth(1)
+    }
+    catch (e: UnsupportedOperationException) {
+        return 2
+    }
+    finally {
+        doSmth(3)
+    }
+}
+
+fun doSmth(i: Int) {
 }
\ No newline at end of file
diff --git a/compiler/testData/checkerWithErrorTypes/full/regression/kt58.jet b/compiler/testData/checkerWithErrorTypes/full/regression/kt58.jet
new file mode 100644
index 00000000000..7ebe0ee8feb
--- /dev/null
+++ b/compiler/testData/checkerWithErrorTypes/full/regression/kt58.jet
@@ -0,0 +1,91 @@
+//KT-58 Allow finally around definite returns
+
+namespace kt58
+
+import java.util.concurrent.locks.Lock
+
+fun lock<T>(lock : Lock, body : fun () : T) : T {
+    lock.lock()
+    try {
+        return body()
+    }
+    finally {
+        lock.unlock(); // we report an error, but we chouldn't
+    }
+}
+
+//more tests
+fun t1() : Int {
+    try {
+        <!UNREACHABLE_CODE!>return 1<!>
+    }
+    finally {
+        return 2
+    }
+}
+
+fun t2() : Int {
+    try {
+        return 1
+    }
+    finally {
+        doSmth(3)
+    }
+}
+
+fun t3() : Int {
+    try {
+        return 1
+    }
+    catch (e: UnsupportedOperationException) {
+        doSmth(2)
+    }
+    finally {
+        <!NO_RETURN_IN_FUNCTION_WITH_BLOCK_BODY!>doSmth(3)<!>
+    }
+}
+
+fun t4() : Int {
+    try {
+        return 1
+    }
+    catch (e: UnsupportedOperationException) {
+        <!NO_RETURN_IN_FUNCTION_WITH_BLOCK_BODY!>doSmth(2)<!>
+    }
+}
+
+fun t5() : Int {
+    try {
+        return 1
+    }
+    catch (e: UnsupportedOperationException) {
+        return 2
+    }
+}
+
+fun t6() : Int {
+    try {
+        return 1
+    }
+    catch (e: UnsupportedOperationException) {
+        return 2
+    }
+    finally {
+        doSmth(3)
+    }
+}
+
+fun t7() : Int {
+    try {
+        doSmth(1)
+    }
+    catch (e: UnsupportedOperationException) {
+        return 2
+    }
+    finally {
+        <!NO_RETURN_IN_FUNCTION_WITH_BLOCK_BODY!>doSmth(3)<!>
+    }
+}
+
+fun doSmth(i: Int) {
+}
\ No newline at end of file
diff --git a/compiler/tests/org/jetbrains/jet/cfg/JetControlFlowTest.java b/compiler/tests/org/jetbrains/jet/cfg/JetControlFlowTest.java
index 2a3e2780fc3..3a63dc0f92c 100644
--- a/compiler/tests/org/jetbrains/jet/cfg/JetControlFlowTest.java
+++ b/compiler/tests/org/jetbrains/jet/cfg/JetControlFlowTest.java
@@ -3,6 +3,7 @@
  */
 package org.jetbrains.jet.cfg;
 
+import com.google.common.collect.Sets;
 import com.intellij.openapi.util.io.FileUtil;
 import com.intellij.openapi.util.text.StringUtil;
 import junit.framework.Test;
@@ -125,7 +126,7 @@ public class JetControlFlowTest extends JetLiteFixture {
             instructionDump.append("=====================\n");
             
             //check edges directions
-            Collection<Instruction> instructions = pseudocode.getInstructions();
+            Collection<Instruction> instructions = pseudocode.getMutableInstructionList();
             for (Instruction instruction : instructions) {
                 if (!instruction.isDead()) {
                     for (Instruction nextInstruction : instruction.getNextInstructions()) {
@@ -157,7 +158,7 @@ public class JetControlFlowTest extends JetLiteFixture {
     }
 
     public void dfsDump(Pseudocode pseudocode, StringBuilder nodes, StringBuilder edges, Map<Instruction, String> nodeNames) {
-        dfsDump(nodes, edges, pseudocode.getInstructions().get(0), nodeNames);
+        dfsDump(nodes, edges, pseudocode.getMutableInstructionList().get(0), nodeNames);
     }
 
     private void dfsDump(StringBuilder nodes, StringBuilder edges, Instruction instruction, Map<Instruction, String> nodeNames) {
@@ -172,9 +173,10 @@ public class JetControlFlowTest extends JetLiteFixture {
         throw new UnsupportedOperationException(); // TODO
     }
 
-    private static String formatInstruction(Instruction instruction, int maxLength) {
+    private static String formatInstruction(Instruction instruction, int maxLength, Set<Instruction> remainedAfterPostProcessInstructions) {
         String[] parts = instruction.toString().split("\n");
-        String prefix = instruction.isDead() ? "*   " : "    ";
+        boolean isRemovedThroughPostProcess = !remainedAfterPostProcessInstructions.contains(instruction);
+        String prefix = isRemovedThroughPostProcess ? "R   " : instruction.isDead() ? "*   " : "    ";
         if (parts.length == 1) {
             return prefix + String.format("%1$-" + maxLength + "s", instruction);
         }
@@ -218,7 +220,8 @@ public class JetControlFlowTest extends JetLiteFixture {
     }
 
     public void dumpInstructions(Pseudocode pseudocode, @NotNull StringBuilder out) {
-        List<Instruction> instructions = pseudocode.getInstructions();
+        List<Instruction> instructions = pseudocode.getMutableInstructionList();
+        Set<Instruction> remainedAfterPostProcessInstructions = Sets.newHashSet(pseudocode.getInstructions());
         List<Pseudocode.PseudocodeLabel> labels = pseudocode.getLabels();
         List<Pseudocode> locals = new ArrayList<Pseudocode>();
         int maxLength = 0;
@@ -257,7 +260,7 @@ public class JetControlFlowTest extends JetLiteFixture {
                 }
             }
 
-            out.append(formatInstruction(instruction, maxLength)).
+            out.append(formatInstruction(instruction, maxLength, remainedAfterPostProcessInstructions)).
                     append("    NEXT:").append(String.format("%1$-" + maxNextLength + "s", formatInstructionList(instruction.getNextInstructions()))).
                     append("    PREV:").append(formatInstructionList(instruction.getPreviousInstructions())).append("\n");
         }
@@ -273,7 +276,7 @@ public class JetControlFlowTest extends JetLiteFixture {
                 public void visitLocalDeclarationInstruction(LocalDeclarationInstruction instruction) {
                     int index = count[0];
 //                    instruction.getBody().dumpSubgraph(out, "subgraph cluster_" + index, count, "color=blue;\nlabel = \"f" + index + "\";", nodeToName);
-                    printEdge(out, nodeToName.get(instruction), nodeToName.get(instruction.getBody().getInstructions().get(0)), null);
+                    printEdge(out, nodeToName.get(instruction), nodeToName.get(instruction.getBody().getMutableInstructionList().get(0)), null);
                     visitInstructionWithNext(instruction);
                 }
 
@@ -336,7 +339,7 @@ public class JetControlFlowTest extends JetLiteFixture {
         }
     }
 
-    public void dumpNodes(List<Instruction> instructions, PrintStream out, int[] count, Map<Instruction, String> nodeToName) {
+    public void dumpNodes(List<Instruction> instructions, PrintStream out, int[] count, Map<Instruction, String> nodeToName, Set<Instruction> remainedAfterPostProcessInstructions) {
         for (Instruction node : instructions) {
             String name = "n" + count[0]++;
             nodeToName.put(node, name);
@@ -361,6 +364,9 @@ public class JetControlFlowTest extends JetLiteFixture {
             else if (node instanceof SubroutineEnterInstruction || node instanceof SubroutineExitInstruction) {
                 shape = "roundrect, style=rounded";
             }
+            if (!remainedAfterPostProcessInstructions.contains(node)) {
+                shape += "box, fillcolor=grey, style=filled";
+            }
             out.println(name + "[label=\"" + text + "\", shape=" + shape + "];");
         }
     }
@@ -385,7 +391,7 @@ public class JetControlFlowTest extends JetLiteFixture {
         int[] count = new int[1];
         Map<Instruction, String> nodeToName = new HashMap<Instruction, String>();
         for (Pseudocode pseudocode : pseudocodes) {
-            dumpNodes(pseudocode.getInstructions(), out, count, nodeToName);
+            dumpNodes(pseudocode.getMutableInstructionList(), out, count, nodeToName, Sets.newHashSet(pseudocode.getInstructions()));
         }
         int i = 0;
         for (Pseudocode pseudocode : pseudocodes) {
@@ -401,7 +407,7 @@ public class JetControlFlowTest extends JetLiteFixture {
             out.println("subgraph cluster_" + i + " {\n" +
                         "label=\"" + label + "\";\n" +
                         "color=blue;\n");
-            dumpEdges(pseudocode.getInstructions(), out, count, nodeToName);
+            dumpEdges(pseudocode.getMutableInstructionList(), out, count, nodeToName);
             out.println("}");
             i++;
         }