diff --git a/src/main/java/com/google/devtools/common/options/InvocationPolicyEnforcer.java b/src/main/java/com/google/devtools/common/options/InvocationPolicyEnforcer.java
index 8b5ba08..59d1a41 100644
--- a/src/main/java/com/google/devtools/common/options/InvocationPolicyEnforcer.java
+++ b/src/main/java/com/google/devtools/common/options/InvocationPolicyEnforcer.java
@@ -232,7 +232,7 @@
         String.format("Disallow_Values on expansion flags like %s is not allowed.", flagName));
   }
 
-  private static ImmutableList<OptionValueDescription> getExpansionsFromFlagPolicy(
+  private static ImmutableList<UnparsedOptionValueDescription> getExpansionsFromFlagPolicy(
       FlagPolicy expansionPolicy, OptionDescription optionDescription, OptionsParser parser)
       throws OptionsParsingException {
     if (!optionDescription.isExpansion()) {
@@ -248,7 +248,7 @@
             optionDescription.getOptionDefinition().getOptionName(),
             expansionPolicy.getFlagName()));
 
-    ImmutableList.Builder<OptionValueDescription> resultsBuilder = ImmutableList.builder();
+    ImmutableList.Builder<UnparsedOptionValueDescription> resultsBuilder = ImmutableList.builder();
     switch (expansionPolicy.getOperationCase()) {
       case SET_VALUE:
         {
@@ -327,10 +327,10 @@
       return expandedPolicies;
     }
 
-    ImmutableList<OptionValueDescription> expansions =
+    ImmutableList<UnparsedOptionValueDescription> expansions =
         getExpansionsFromFlagPolicy(originalPolicy, originalOptionDescription, parser);
-    ImmutableList.Builder<OptionValueDescription> subflagBuilder = ImmutableList.builder();
-    ImmutableList<OptionValueDescription> subflags =
+    ImmutableList.Builder<UnparsedOptionValueDescription> subflagBuilder = ImmutableList.builder();
+    ImmutableList<UnparsedOptionValueDescription> subflags =
         subflagBuilder
             .addAll(originalOptionDescription.getImplicitRequirements())
             .addAll(expansions)
@@ -342,7 +342,7 @@
       // only really useful for understanding the invocation policy itself. Most of the time,
       // invocation policy does not change, so this can be a log level fine.
       List<String> subflagNames = new ArrayList<>(subflags.size());
-      for (OptionValueDescription subflag : subflags) {
+      for (UnparsedOptionValueDescription subflag : subflags) {
         subflagNames.add("--" + subflag.getOptionDefinition().getOptionName());
       }
 
@@ -360,13 +360,13 @@
 
     // Repeated flags are special, and could set multiple times in an expansion, with the user
     // expecting both values to be valid. Collect these separately.
-    Multimap<OptionDefinition, OptionValueDescription> repeatableSubflagsInSetValues =
+    Multimap<OptionDefinition, UnparsedOptionValueDescription> repeatableSubflagsInSetValues =
         ArrayListMultimap.create();
 
     // Create a flag policy for the child that looks like the parent's policy "transferred" to its
     // child. Note that this only makes sense for SetValue, when setting an expansion flag, or
     // UseDefault, when preventing it from being set.
-    for (OptionValueDescription currentSubflag : subflags) {
+    for (UnparsedOptionValueDescription currentSubflag : subflags) {
       if (currentSubflag.getOptionDefinition().allowsMultiple()
           && originalPolicy.getOperationCase().equals(OperationCase.SET_VALUE)) {
         repeatableSubflagsInSetValues.put(currentSubflag.getOptionDefinition(), currentSubflag);
@@ -384,8 +384,9 @@
     for (OptionDefinition repeatableFlag : repeatableSubflagsInSetValues.keySet()) {
       int numValues = repeatableSubflagsInSetValues.get(repeatableFlag).size();
       ArrayList<String> newValues = new ArrayList<>(numValues);
-      for (OptionValueDescription setValue : repeatableSubflagsInSetValues.get(repeatableFlag)) {
-        newValues.add(setValue.getOriginalValueString());
+      for (UnparsedOptionValueDescription setValue :
+          repeatableSubflagsInSetValues.get(repeatableFlag)) {
+        newValues.add(setValue.getUnconvertedValue());
       }
       expandedPolicies.add(getSetValueSubflagAsPolicy(repeatableFlag, newValues, originalPolicy));
     }
@@ -443,7 +444,7 @@
    * corresponding policy.
    */
   private static FlagPolicy getSingleValueSubflagAsPolicy(
-      OptionValueDescription currentSubflag, FlagPolicy originalPolicy, boolean isExpansion)
+      UnparsedOptionValueDescription currentSubflag, FlagPolicy originalPolicy, boolean isExpansion)
       throws OptionsParsingException {
     FlagPolicy subflagAsPolicy = null;
     switch (originalPolicy.getOperationCase()) {
@@ -456,10 +457,10 @@
         // Accept null originalValueStrings, they are expected when the subflag is also an expansion
         // flag.
         List<String> subflagValue;
-        if (currentSubflag.getOriginalValueString() == null) {
+        if (currentSubflag.getUnconvertedValue() == null) {
           subflagValue = ImmutableList.of();
         } else {
-          subflagValue = ImmutableList.of(currentSubflag.getOriginalValueString());
+          subflagValue = ImmutableList.of(currentSubflag.getUnconvertedValue());
         }
         subflagAsPolicy =
             getSetValueSubflagAsPolicy(
diff --git a/src/main/java/com/google/devtools/common/options/OptionsParser.java b/src/main/java/com/google/devtools/common/options/OptionsParser.java
index 68a9f02..881fb38 100644
--- a/src/main/java/com/google/devtools/common/options/OptionsParser.java
+++ b/src/main/java/com/google/devtools/common/options/OptionsParser.java
@@ -235,12 +235,12 @@
 
     private final OptionDefinition optionDefinition;
     private final OptionsData.ExpansionData expansionData;
-    private final ImmutableList<OptionValueDescription> implicitRequirements;
+    private final ImmutableList<UnparsedOptionValueDescription> implicitRequirements;
 
     OptionDescription(
         OptionDefinition definition,
         OptionsData.ExpansionData expansionData,
-        ImmutableList<OptionValueDescription> implicitRequirements) {
+        ImmutableList<UnparsedOptionValueDescription> implicitRequirements) {
       this.optionDefinition = definition;
       this.expansionData = expansionData;
       this.implicitRequirements = implicitRequirements;
@@ -250,7 +250,7 @@
       return optionDefinition;
     }
 
-    public ImmutableList<OptionValueDescription> getImplicitRequirements() {
+    public ImmutableList<UnparsedOptionValueDescription> getImplicitRequirements() {
       return implicitRequirements;
     }
 
@@ -417,7 +417,7 @@
    * @return The {@link com.google.devtools.common.options.OptionValueDescription>} for the option,
    *     or null if there is no option by the given name.
    */
-  ImmutableList<OptionValueDescription> getExpansionOptionValueDescriptions(
+  ImmutableList<UnparsedOptionValueDescription> getExpansionOptionValueDescriptions(
       OptionDefinition option, @Nullable String optionValue, OptionPriority priority, String source)
       throws OptionsParsingException {
     return impl.getExpansionOptionValueDescriptions(option, optionValue, priority, source);
diff --git a/src/main/java/com/google/devtools/common/options/OptionsParserImpl.java b/src/main/java/com/google/devtools/common/options/OptionsParserImpl.java
index 5e58435..b79e72d 100644
--- a/src/main/java/com/google/devtools/common/options/OptionsParserImpl.java
+++ b/src/main/java/com/google/devtools/common/options/OptionsParserImpl.java
@@ -200,16 +200,17 @@
 
   // Warnings should not end with a '.' because the internal reporter adds one automatically.
   private void setValue(
-      OptionDefinition optionDefinition,
-      Object value,
-      OptionPriority priority,
-      String source,
+      UnparsedOptionValueDescription optionValue,
       OptionDefinition implicitDependant,
-      OptionDefinition expandedFrom) {
-    OptionValueDescription entry = parsedValues.get(optionDefinition);
+      OptionDefinition expandedFrom)
+      throws OptionsParsingException {
+    OptionDefinition optionDefinition = optionValue.getOptionDefinition();
+    Preconditions.checkArgument(!optionDefinition.allowsMultiple());
+    Object convertedValue = optionValue.getConvertedValue();
+    OptionValueDescription entry = parsedValues.get(optionValue.getOptionDefinition());
     if (entry != null) {
       // Override existing option if the new value has higher or equal priority.
-      if (priority.compareTo(entry.getPriority()) >= 0) {
+      if (optionValue.getPriority().compareTo(entry.getPriority()) >= 0) {
         // Output warnings:
         if ((implicitDependant != null) && (entry.getImplicitDependant() != null)) {
           if (!implicitDependant.equals(entry.getImplicitDependant())) {
@@ -222,7 +223,8 @@
                     + implicitDependant.getOptionName()
                     + "'");
           }
-        } else if ((implicitDependant != null) && priority.equals(entry.getPriority())) {
+        } else if ((implicitDependant != null)
+            && optionValue.getPriority().equals(entry.getPriority())) {
           warnings.add(
               "Option '"
                   + optionDefinition.getOptionName()
@@ -236,7 +238,7 @@
                   + "' overrides a previous implicit setting of that option by option '"
                   + entry.getImplicitDependant().getOptionName()
                   + "'");
-        } else if ((priority == entry.getPriority())
+        } else if ((optionValue.getPriority() == entry.getPriority())
             && ((entry.getExpansionParent() == null) && (expandedFrom != null))) {
           // Create a warning if an expansion option overrides an explicit option:
           warnings.add(
@@ -261,24 +263,37 @@
         parsedValues.put(
             optionDefinition,
             OptionValueDescription.newOptionValue(
-                optionDefinition, null, value, priority, source, implicitDependant, expandedFrom));
+                optionDefinition,
+                null,
+                convertedValue,
+                optionValue.getPriority(),
+                optionValue.getSource(),
+                implicitDependant,
+                expandedFrom));
       }
     } else {
       parsedValues.put(
           optionDefinition,
           OptionValueDescription.newOptionValue(
-              optionDefinition, null, value, priority, source, implicitDependant, expandedFrom));
+              optionDefinition,
+              null,
+              convertedValue,
+              optionValue.getPriority(),
+              optionValue.getSource(),
+              implicitDependant,
+              expandedFrom));
       maybeAddDeprecationWarning(optionDefinition);
     }
   }
 
   private void addListValue(
-      OptionDefinition optionDefinition,
-      Object value,
-      OptionPriority priority,
-      String source,
+      UnparsedOptionValueDescription optionValue,
       OptionDefinition implicitDependant,
-      OptionDefinition expandedFrom) {
+      OptionDefinition expandedFrom)
+      throws OptionsParsingException {
+    OptionDefinition optionDefinition = optionValue.getOptionDefinition();
+    Preconditions.checkArgument(optionDefinition.allowsMultiple());
+
     OptionValueDescription entry = parsedValues.get(optionDefinition);
     if (entry == null) {
       entry =
@@ -286,14 +301,15 @@
               optionDefinition,
               /* originalValueString */ null,
               ArrayListMultimap.create(),
-              priority,
-              source,
+              optionValue.getPriority(),
+              optionValue.getSource(),
               implicitDependant,
               expandedFrom);
       parsedValues.put(optionDefinition, entry);
       maybeAddDeprecationWarning(optionDefinition);
     }
-    entry.addValue(priority, value);
+    Object convertedValue = optionValue.getConvertedValue();
+    entry.addValue(optionValue.getPriority(), convertedValue);
   }
 
   OptionValueDescription clearValue(OptionDefinition optionDefinition)
@@ -329,13 +345,13 @@
   }
 
   /** @return A list of the descriptions corresponding to the implicit dependant flags passed in. */
-  private ImmutableList<OptionValueDescription> getImplicitDependantDescriptions(
+  private ImmutableList<UnparsedOptionValueDescription> getImplicitDependantDescriptions(
       ImmutableList<String> options,
       OptionDefinition implicitDependant,
       OptionPriority priority,
       String source)
       throws OptionsParsingException {
-    ImmutableList.Builder<OptionValueDescription> builder = ImmutableList.builder();
+    ImmutableList.Builder<UnparsedOptionValueDescription> builder = ImmutableList.builder();
     Iterator<String> optionsIterator = options.iterator();
 
     Function<OptionDefinition, String> sourceFunction =
@@ -348,15 +364,7 @@
       UnparsedOptionValueDescription unparsedOption =
           identifyOptionAndPossibleArgument(
               unparsedFlagExpression, optionsIterator, priority, sourceFunction, false);
-      builder.add(
-          OptionValueDescription.newOptionValue(
-              unparsedOption.getOptionDefinition(),
-              unparsedOption.getUnconvertedValue(),
-              /* value */ null,
-              unparsedOption.getPriority(),
-              unparsedOption.getSource(),
-              implicitDependant,
-              /* expendedFrom */ null));
+      builder.add(unparsedOption);
     }
     return builder.build();
   }
@@ -367,13 +375,13 @@
    *     correct priority or source for these, as they are not actually set values. The value itself
    *     is also a string, no conversion has taken place.
    */
-  ImmutableList<OptionValueDescription> getExpansionOptionValueDescriptions(
+  ImmutableList<UnparsedOptionValueDescription> getExpansionOptionValueDescriptions(
       OptionDefinition expansionFlag,
       @Nullable String flagValue,
       OptionPriority priority,
       String source)
       throws OptionsParsingException {
-    ImmutableList.Builder<OptionValueDescription> builder = ImmutableList.builder();
+    ImmutableList.Builder<UnparsedOptionValueDescription> builder = ImmutableList.builder();
 
     ImmutableList<String> options = optionsData.getEvaluatedExpansion(expansionFlag, flagValue);
     Iterator<String> optionsIterator = options.iterator();
@@ -384,15 +392,7 @@
       UnparsedOptionValueDescription unparsedOption =
           identifyOptionAndPossibleArgument(
               unparsedFlagExpression, optionsIterator, priority, sourceFunction, false);
-      builder.add(
-          OptionValueDescription.newOptionValue(
-              unparsedOption.getOptionDefinition(),
-              unparsedOption.getUnconvertedValue(),
-              /* value */ null,
-              unparsedOption.getPriority(),
-              unparsedOption.getSource(),
-              /* implicitDependant */ null,
-              expansionFlag));
+      builder.add(unparsedOption);
     }
     return builder.build();
   }
@@ -528,40 +528,14 @@
                   + Joiner.on(' ').join(unparsed));
         }
       } else {
-        Converter<?> converter = optionDefinition.getConverter();
-        Object convertedValue;
-        try {
-          convertedValue = converter.convert(unconvertedValue);
-        } catch (OptionsParsingException e) {
-          // The converter doesn't know the option name, so we supply it here by
-          // re-throwing:
-          throw new OptionsParsingException("While parsing option " + arg
-                                            + ": " + e.getMessage(), e);
-        }
-
         // ...but allow duplicates of single-use options across separate calls to
         // parse(); latest wins:
         if (!optionDefinition.allowsMultiple()) {
-          setValue(
-              optionDefinition,
-              convertedValue,
-              priority,
-              sourceFunction.apply(optionDefinition),
-              implicitDependent,
-              expandedFrom);
+          setValue(unparsedOption, implicitDependent, expandedFrom);
         } else {
-          // But if it's a multiple-use option, then just accumulate the
-          // values, in the order in which they were seen.
-          // Note: The type of the list member is not known; Java introspection
-          // only makes it available in String form via the signature string
-          // for the field declaration.
-          addListValue(
-              optionDefinition,
-              convertedValue,
-              priority,
-              sourceFunction.apply(optionDefinition),
-              implicitDependent,
-              expandedFrom);
+          // But if it's a multiple-use option, then accumulate the values, in the order in which
+          // they were seen.
+          addListValue(unparsedOption, implicitDependent, expandedFrom);
         }
       }
 
@@ -605,6 +579,9 @@
       boolean explicit)
       throws OptionsParsingException {
 
+    // Store the way this option was parsed on the command line.
+    StringBuilder commandLineForm = new StringBuilder();
+    commandLineForm.append(arg);
     String unparsedValue = null;
     OptionDefinition optionDefinition;
     boolean booleanValue = true;
@@ -668,7 +645,9 @@
           && !optionDefinition.isWrapperOption()) {
         // This is expected, Void type options have no args (unless they're wrapper options).
       } else if (nextArgs.hasNext()) {
-        unparsedValue = nextArgs.next(); // "--flag value" form
+        // "--flag value" form
+        unparsedValue = nextArgs.next();
+        commandLineForm.append(" ").append(unparsedValue);
       } else {
         throw new OptionsParsingException("Expected value after " + arg);
       }
@@ -676,6 +655,7 @@
 
     return new UnparsedOptionValueDescription(
         optionDefinition,
+        commandLineForm.toString(),
         unparsedValue,
         priority,
         sourceFunction.apply(optionDefinition),
diff --git a/src/main/java/com/google/devtools/common/options/UnparsedOptionValueDescription.java b/src/main/java/com/google/devtools/common/options/UnparsedOptionValueDescription.java
index 8cd858a..c6fbbf7 100644
--- a/src/main/java/com/google/devtools/common/options/UnparsedOptionValueDescription.java
+++ b/src/main/java/com/google/devtools/common/options/UnparsedOptionValueDescription.java
@@ -23,11 +23,12 @@
  * <p>This class represents an option as the parser received it, which is distinct from the final
  * value of an option, as these values may be overridden or combined in some way.
  *
- * <p>The origin includes the value it was set to, its priority, a message about where it came
+ * <p>The origin includes the form it had when parsed, its priority, a message about where it came
  * from, and whether it was set explicitly or expanded/implied by other flags.
  */
 public final class UnparsedOptionValueDescription {
   private final OptionDefinition optionDefinition;
+  private final String commandLineForm;
   @Nullable private final String unconvertedValue;
   private final OptionPriority priority;
   @Nullable private final String source;
@@ -39,11 +40,13 @@
 
   public UnparsedOptionValueDescription(
       OptionDefinition optionDefinition,
+      String commandLineForm,
       @Nullable String unconvertedValue,
       OptionPriority priority,
       @Nullable String source,
       boolean explicit) {
     this.optionDefinition = optionDefinition;
+    this.commandLineForm = commandLineForm;
     this.unconvertedValue = unconvertedValue;
     this.priority = priority;
     this.source = source;
@@ -54,6 +57,10 @@
     return optionDefinition;
   }
 
+  public String getCommandLineForm() {
+    return commandLineForm;
+  }
+
   public boolean isBooleanOption() {
     return optionDefinition.getType().equals(boolean.class);
   }
@@ -99,6 +106,17 @@
     return explicit;
   }
 
+  public Object getConvertedValue() throws OptionsParsingException {
+    Converter<?> converter = optionDefinition.getConverter();
+    try {
+      return converter.convert(unconvertedValue);
+    } catch (OptionsParsingException e) {
+      // The converter doesn't know the option name, so we supply it here by re-throwing:
+      throw new OptionsParsingException(
+          String.format("While parsing option %s: %s", commandLineForm, e.getMessage()), e);
+    }
+  }
+
   @Override
   public String toString() {
     StringBuilder result = new StringBuilder();