diff --git a/src/main/java/com/google/devtools/build/lib/events/Event.java b/src/main/java/com/google/devtools/build/lib/events/Event.java
index c35e769..27c122e 100644
--- a/src/main/java/com/google/devtools/build/lib/events/Event.java
+++ b/src/main/java/com/google/devtools/build/lib/events/Event.java
@@ -18,6 +18,8 @@
 import com.google.common.base.Preconditions;
 
 import java.io.Serializable;
+import java.util.Arrays;
+import java.util.Objects;
 import javax.annotation.Nullable;
 import javax.annotation.concurrent.Immutable;
 
@@ -116,6 +118,24 @@
         + getMessage();
   }
 
+  @Override
+  public int hashCode() {
+    return Objects.hash(kind, location, message, tag, Arrays.hashCode(messageBytes));
+  }
+
+  @Override
+  public boolean equals(Object other) {
+    if (other == null || !other.getClass().equals(getClass())) {
+      return false;
+    }
+    Event that = (Event) other;
+    return Objects.equals(this.kind, that.kind)
+        && Objects.equals(this.location, that.location)
+        && Objects.equals(this.tag, that.tag)
+        && Objects.equals(this.message, that.message)
+        && Arrays.equals(this.messageBytes, that.messageBytes);
+  }
+
   /**
    * Replay a sequence of events on an {@link EventHandler}.
    */
diff --git a/src/main/java/com/google/devtools/build/lib/events/Location.java b/src/main/java/com/google/devtools/build/lib/events/Location.java
index 160d4a5..58301b7 100644
--- a/src/main/java/com/google/devtools/build/lib/events/Location.java
+++ b/src/main/java/com/google/devtools/build/lib/events/Location.java
@@ -19,6 +19,7 @@
 import com.google.devtools.build.lib.vfs.PathFragment;
 
 import java.io.Serializable;
+import java.util.Objects;
 
 /**
  * A Location is a range of characters within a file.
@@ -52,6 +53,22 @@
     public LineAndColumn getStartLineAndColumn() {
       return startLineAndColumn;
     }
+
+    @Override
+    public int hashCode() {
+      return Objects.hash(path, startLineAndColumn, internalHashCode());
+    }
+
+    @Override
+    public boolean equals(Object other) {
+      if (other == null || !other.getClass().equals(getClass())) {
+        return false;
+      }
+      LocationWithPathAndStartColumn that = (LocationWithPathAndStartColumn) other;
+      return internalEquals(that)
+          && Objects.equals(this.path, that.path)
+          && Objects.equals(this.startLineAndColumn, that.startLineAndColumn);
+    }
   }
 
   protected final int startOffset;
@@ -212,6 +229,14 @@
     return print();
   }
 
+  protected int internalHashCode() {
+    return Objects.hash(startOffset, endOffset);
+  }
+
+  protected boolean internalEquals(Location that) {
+    return this.startOffset == that.startOffset && this.endOffset == that.endOffset;
+  }
+
   /**
    * A value class that describes the line and column of an offset in a file.
    */
@@ -247,7 +272,7 @@
 
     @Override
     public int hashCode() {
-      return line * 81 + column;
+      return line * 41 + column;
     }
   }
 }
diff --git a/src/main/java/com/google/devtools/build/lib/packages/PackageDeserializer.java b/src/main/java/com/google/devtools/build/lib/packages/PackageDeserializer.java
index d5a612e..1f2c609 100644
--- a/src/main/java/com/google/devtools/build/lib/packages/PackageDeserializer.java
+++ b/src/main/java/com/google/devtools/build/lib/packages/PackageDeserializer.java
@@ -43,6 +43,7 @@
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Set;
 import java.util.logging.Level;
 import java.util.logging.Logger;
@@ -197,6 +198,26 @@
     public LineAndColumn getEndLineAndColumn() {
       return new LineAndColumn(endLine, endColumn);
     }
+
+    @Override
+    public int hashCode() {
+      return Objects.hash(
+          path.hashCode(), startLine, startColumn, endLine, endColumn, internalHashCode());
+    }
+
+    @Override
+    public boolean equals(Object other) {
+      if (other == null || !other.getClass().equals(getClass())) {
+        return false;
+      }
+      ExplicitLocation that = (ExplicitLocation) other;
+      return this.startLine == that.startLine
+          && this.startColumn == that.startColumn
+          && this.endLine == that.endLine
+          && this.endColumn == that.endColumn
+          && internalEquals(that)
+          && Objects.equals(this.path, that.path);
+    }
   }
 
   /**
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/Lexer.java b/src/main/java/com/google/devtools/build/lib/syntax/Lexer.java
index c4a58a9..90b40e3 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/Lexer.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/Lexer.java
@@ -26,6 +26,7 @@
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Stack;
 
 /**
@@ -182,6 +183,21 @@
     public LineAndColumn getEndLineAndColumn() {
       return lineNumberTable.getLineAndColumn(getEndOffset());
     }
+
+
+    @Override
+    public int hashCode() {
+      return Objects.hash(lineNumberTable, internalHashCode());
+    }
+
+    @Override
+    public boolean equals(Object other) {
+      if (other == null || !other.getClass().equals(getClass())) {
+        return false;
+      }
+      LexerLocation that = (LexerLocation) other;
+      return internalEquals(that) && Objects.equals(this.lineNumberTable, that.lineNumberTable);
+    }
   }
 
   /** invariant: symbol positions are half-open intervals. */
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/LineNumberTable.java b/src/main/java/com/google/devtools/build/lib/syntax/LineNumberTable.java
index 3bcf0a0..ac629c7 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/LineNumberTable.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/LineNumberTable.java
@@ -25,8 +25,10 @@
 import java.io.Serializable;
 import java.nio.CharBuffer;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Comparator;
 import java.util.List;
+import java.util.Objects;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -146,6 +148,23 @@
           ? linestart[line + 1]
           : bufferLength);
     }
+
+
+    @Override
+    public int hashCode() {
+      return Objects.hash(Arrays.hashCode(linestart), path, bufferLength);
+    }
+
+    @Override
+    public boolean equals(Object other) {
+      if (other == null || !other.getClass().equals(getClass())) {
+        return false;
+      }
+      Regular that = (Regular) other;
+      return this.bufferLength == that.bufferLength
+          && Arrays.equals(this.linestart, that.linestart)
+          && Objects.equals(this.path, that.path);
+    }
   }
 
   /**
@@ -197,7 +216,7 @@
       }
       this.table = hashOrdering.immutableSortedCopy(unorderedTable);
       this.bufferLength = buffer.length;
-      this.defaultPath = defaultPath;
+      this.defaultPath = Preconditions.checkNotNull(defaultPath);
     }
 
     private SingleHashLine getHashLine(int offset) {
@@ -242,5 +261,21 @@
       }
       return Pair.of(0, 0);
     }
+
+    @Override
+    public int hashCode() {
+      return Objects.hash(table, defaultPath, bufferLength);
+    }
+
+    @Override
+    public boolean equals(Object other) {
+      if (other == null || !other.getClass().equals(getClass())) {
+        return false;
+      }
+      HashLine that = (HashLine) other;
+      return this.bufferLength == that.bufferLength
+          && this.defaultPath.equals(that.defaultPath)
+          && this.table.equals(that.table);
+    }
   }
 }
diff --git a/src/main/java/com/google/devtools/build/skyframe/TaggedEvents.java b/src/main/java/com/google/devtools/build/skyframe/TaggedEvents.java
index b285b62..394f186 100644
--- a/src/main/java/com/google/devtools/build/skyframe/TaggedEvents.java
+++ b/src/main/java/com/google/devtools/build/skyframe/TaggedEvents.java
@@ -18,6 +18,7 @@
 import com.google.devtools.build.lib.events.Event;
 
 import java.io.Serializable;
+import java.util.Objects;
 import javax.annotation.Nullable;
 import javax.annotation.concurrent.Immutable;
 
@@ -60,4 +61,18 @@
   public String toString() {
     return tag == null ? "<unknown>" : tag + ": " + Iterables.toString(events);
   }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(tag, events);
+  }
+
+  @Override
+  public boolean equals(Object other) {
+    if (other == null || !other.getClass().equals(getClass())) {
+      return false;
+    }
+    TaggedEvents that = (TaggedEvents) other;
+    return Objects.equals(this.tag, that.tag) && Objects.equals(this.events, that.events);
+  }
 }
diff --git a/src/main/java/com/google/devtools/build/skyframe/ValueWithMetadata.java b/src/main/java/com/google/devtools/build/skyframe/ValueWithMetadata.java
index e153a68..3795832 100644
--- a/src/main/java/com/google/devtools/build/skyframe/ValueWithMetadata.java
+++ b/src/main/java/com/google/devtools/build/skyframe/ValueWithMetadata.java
@@ -116,7 +116,7 @@
 
     @Override
     public int hashCode() {
-      return 31 * value.hashCode() + transitiveEvents.hashCode();
+      return 31 * value.hashCode() + transitiveEvents.shallowHashCode();
     }
 
     @Override
diff --git a/src/test/java/com/google/devtools/build/skyframe/MemoizingEvaluatorTest.java b/src/test/java/com/google/devtools/build/skyframe/MemoizingEvaluatorTest.java
index 39eb368..e13da02 100644
--- a/src/test/java/com/google/devtools/build/skyframe/MemoizingEvaluatorTest.java
+++ b/src/test/java/com/google/devtools/build/skyframe/MemoizingEvaluatorTest.java
@@ -2401,7 +2401,6 @@
     assertFalse(result.hasError());
   }
 
-
   @Test
   public void absentParent() throws Exception {
     initializeTester();
@@ -2420,6 +2419,31 @@
     assertThat(error.getRootCauses()).containsExactly(errorKey);
   }
 
+  @Test
+  public void changePruningWithEvent() throws Exception {
+    initializeTester();
+    SkyKey parent = GraphTester.toSkyKey("parent");
+    SkyKey child = GraphTester.toSkyKey("child");
+    tester.getOrCreate(child).setConstantValue(new StringValue("child")).setWarning("bloop");
+    // Restart once because child isn't ready.
+    CountDownLatch parentEvaluated = new CountDownLatch(3);
+    StringValue parentVal = new StringValue("parent");
+    tester
+        .getOrCreate(parent)
+        .setBuilder(
+            new ChainedFunction(
+                parentEvaluated, null, null, false, parentVal, ImmutableList.of(child)));
+    assertThat(tester.evalAndGet( /*keepGoing=*/false, parent)).isEqualTo(parentVal);
+    assertThat(parentEvaluated.getCount()).isEqualTo(1);
+    JunitTestUtils.assertContainsEvent(eventCollector, "bloop");
+    tester.resetPlayedEvents();
+    tester.getOrCreate(child, /*markAsModified=*/ true);
+    tester.invalidate();
+    assertThat(tester.evalAndGet( /*keepGoing=*/false, parent)).isEqualTo(parentVal);
+    JunitTestUtils.assertContainsEvent(eventCollector, "bloop");
+    assertThat(parentEvaluated.getCount()).isEqualTo(1);
+  }
+
   // Tests that we have a sane implementation of error transience.
   @Test
   public void errorTransienceBug() throws Exception {