diff --git a/src/main/java/com/android/tools/r8/naming/ProguardMapReader.java b/src/main/java/com/android/tools/r8/naming/ProguardMapReader.java
index c1dfb81..749f1ea 100644
--- a/src/main/java/com/android/tools/r8/naming/ProguardMapReader.java
+++ b/src/main/java/com/android/tools/r8/naming/ProguardMapReader.java
@@ -389,11 +389,26 @@
                             MappingInformationDiagnostics.notAllowedCombination(
                                 info, conflictingInfo, lineNo)));
                 if (info.isResidualSignatureMappingInformation()) {
+                  ResidualSignatureMappingInformation mappingInfo =
+                      info.asResidualSignatureMappingInformation();
+                  if (!mappingInfo.isValid()) {
+                    diagnosticsHandler.warning(
+                        MappingInformationDiagnostics.invalidResidualSignature(
+                            line.trim(), lineNo));
+                    return;
+                  }
                   Signature residualSignature =
                       getResidualSignatureFromMappingInformation(
                           info.asResidualSignatureMappingInformation(), currentRenamedNameFinal);
                   currentResidualSignature.set(residualSignature);
                   if (currentRange != null) {
+                    if (!mappingInfo.isResidualMethodSignatureMappingInformation()) {
+                      diagnosticsHandler.warning(
+                          MappingInformationDiagnostics.invalidResidualSignatureType(
+                              info.serialize(), lineNo));
+                      currentResidualSignature.clear();
+                      return;
+                    }
                     currentRange.setResidualSignatureInternal(
                         residualSignature.asMethodSignature());
                   }
@@ -575,7 +590,14 @@
   private Signature getResidualSignatureForMemberNaming(
       Box<Signature> residualSignature, Signature originalSignature, String renamedName) {
     if (residualSignature.isSet()) {
-      return residualSignature.get();
+      if (residualSignature.get().getClass() != originalSignature.getClass()) {
+        diagnosticsHandler.warning(
+            MappingInformationDiagnostics.invalidResidualSignatureType(
+                residualSignature.get().toString(), lineNo));
+
+      } else {
+        return residualSignature.get();
+      }
     }
     Signature signature = originalSignature.asRenamed(renamedName);
     signature = signatureCache.computeIfAbsent(signature, Function.identity());
diff --git a/src/main/java/com/android/tools/r8/naming/mappinginformation/MappingInformationDiagnostics.java b/src/main/java/com/android/tools/r8/naming/mappinginformation/MappingInformationDiagnostics.java
index 1c4242a..cc0da51 100644
--- a/src/main/java/com/android/tools/r8/naming/mappinginformation/MappingInformationDiagnostics.java
+++ b/src/main/java/com/android/tools/r8/naming/mappinginformation/MappingInformationDiagnostics.java
@@ -99,4 +99,21 @@
         "The mapping '" + one + "' is not allowed in combination with '" + other + "'",
         new TextPosition(1, lineNumber, TextPosition.UNKNOWN_COLUMN));
   }
+
+  public static MappingInformationDiagnostics invalidResidualSignature(
+      String info, int lineNumber) {
+    return new MappingInformationDiagnostics(
+        "The residual signature mapping '" + info + "' is invalid'",
+        new TextPosition(1, lineNumber, TextPosition.UNKNOWN_COLUMN));
+  }
+
+  public static MappingInformationDiagnostics invalidResidualSignatureType(
+      String info, int lineNumber) {
+    return new MappingInformationDiagnostics(
+        "The residual signature mapping '"
+            + info
+            + "' is not of the same type as the "
+            + "member it describes.'",
+        new TextPosition(1, lineNumber, TextPosition.UNKNOWN_COLUMN));
+  }
 }
diff --git a/src/main/java/com/android/tools/r8/naming/mappinginformation/ResidualSignatureMappingInformation.java b/src/main/java/com/android/tools/r8/naming/mappinginformation/ResidualSignatureMappingInformation.java
index 05bbad1..db604e3 100644
--- a/src/main/java/com/android/tools/r8/naming/mappinginformation/ResidualSignatureMappingInformation.java
+++ b/src/main/java/com/android/tools/r8/naming/mappinginformation/ResidualSignatureMappingInformation.java
@@ -63,6 +63,8 @@
     }
   }
 
+  public abstract boolean isValid();
+
   @Override
   public boolean isResidualSignatureMappingInformation() {
     return true;
@@ -76,6 +78,9 @@
   public static class ResidualMethodSignatureMappingInformation
       extends ResidualSignatureMappingInformation {
 
+    private static final ResidualMethodSignatureMappingInformation INVALID_METHOD_SIGNATURE =
+        new ResidualMethodSignatureMappingInformation(new String[0], "LINVALID;");
+
     private final String returnType;
     private final String[] parameters;
 
@@ -93,20 +98,27 @@
           parameters, method.getReturnType().toDescriptorString());
     }
 
-    public static ResidualFieldSignatureMappingInformation fromDexField(DexField residualField) {
-      return new ResidualFieldSignatureMappingInformation(
-          residualField.getType().toDescriptorString());
-    }
-
     @Override
     protected String serializeInternal() {
       return StringUtils.join("", Arrays.asList(parameters), BraceType.PARENS) + returnType;
     }
 
+    @Override
+    public boolean isValid() {
+      return this != INVALID_METHOD_SIGNATURE;
+    }
+
     public static ResidualMethodSignatureMappingInformation deserialize(String signature) {
-      return new ResidualMethodSignatureMappingInformation(
-          DescriptorUtils.getArgumentTypeDescriptors(signature),
-          DescriptorUtils.getReturnTypeDescriptor(signature));
+      String[] argumentTypeDescriptors = DescriptorUtils.getArgumentTypeDescriptors(signature);
+      String returnTypeDescriptor = DescriptorUtils.getReturnTypeDescriptor(signature);
+      boolean isValid = DescriptorUtils.isDescriptor(returnTypeDescriptor);
+      for (String argumentTypeDescriptor : argumentTypeDescriptors) {
+        isValid &= DescriptorUtils.isDescriptor(argumentTypeDescriptor);
+      }
+      return isValid
+          ? new ResidualMethodSignatureMappingInformation(
+              argumentTypeDescriptors, returnTypeDescriptor)
+          : INVALID_METHOD_SIGNATURE;
     }
 
     public String getReturnType() {
@@ -148,6 +160,9 @@
   public static class ResidualFieldSignatureMappingInformation
       extends ResidualSignatureMappingInformation {
 
+    private static final ResidualFieldSignatureMappingInformation INVALID_FIELD_SIGNATURE =
+        new ResidualFieldSignatureMappingInformation("LINVALID;");
+
     private final String type;
 
     private ResidualFieldSignatureMappingInformation(String type) {
@@ -168,8 +183,15 @@
       return type;
     }
 
+    @Override
+    public boolean isValid() {
+      return this != INVALID_FIELD_SIGNATURE;
+    }
+
     public static ResidualFieldSignatureMappingInformation deserialize(String signature) {
-      return new ResidualFieldSignatureMappingInformation(signature);
+      return DescriptorUtils.isDescriptor(signature)
+          ? new ResidualFieldSignatureMappingInformation(signature)
+          : INVALID_FIELD_SIGNATURE;
     }
 
     @Override
diff --git a/src/main/java/com/android/tools/r8/utils/positions/MappedPositionToClassNameMapperBuilder.java b/src/main/java/com/android/tools/r8/utils/positions/MappedPositionToClassNameMapperBuilder.java
index b3834cf..7f67d3d 100644
--- a/src/main/java/com/android/tools/r8/utils/positions/MappedPositionToClassNameMapperBuilder.java
+++ b/src/main/java/com/android/tools/r8/utils/positions/MappedPositionToClassNameMapperBuilder.java
@@ -4,6 +4,7 @@
 
 package com.android.tools.r8.utils.positions;
 
+import static com.android.tools.r8.naming.mappinginformation.ResidualSignatureMappingInformation.ResidualFieldSignatureMappingInformation.fromDexField;
 import static com.android.tools.r8.utils.positions.PositionUtils.mustHaveResidualDebugInfo;
 
 import com.android.tools.r8.errors.Unreachable;
@@ -184,9 +185,7 @@
               MemberNaming memberNaming = new MemberNaming(originalSignature, residualSignature);
               if (ResidualSignatureMappingInformation.isSupported(mapFileVersion)
                   && !originalSignature.type.equals(residualSignature.type)) {
-                memberNaming.addMappingInformation(
-                    ResidualMethodSignatureMappingInformation.fromDexField(residualField),
-                    Unreachable::raise);
+                memberNaming.addMappingInformation(fromDexField(residualField), Unreachable::raise);
               }
               if (dexEncodedField.isD8R8Synthesized()) {
                 memberNaming.addMappingInformation(
diff --git a/src/test/java/com/android/tools/r8/retrace/RetraceInvalidResidualSignatureTest.java b/src/test/java/com/android/tools/r8/retrace/RetraceInvalidResidualSignatureTest.java
index 5be9fc2..7663ee1 100644
--- a/src/test/java/com/android/tools/r8/retrace/RetraceInvalidResidualSignatureTest.java
+++ b/src/test/java/com/android/tools/r8/retrace/RetraceInvalidResidualSignatureTest.java
@@ -4,12 +4,14 @@
 
 package com.android.tools.r8.retrace;
 
-import static org.junit.Assert.assertThrows;
+import static org.hamcrest.CoreMatchers.containsString;
 
-import com.android.tools.r8.DiagnosticsHandler;
+import com.android.tools.r8.DiagnosticsMatcher;
 import com.android.tools.r8.TestBase;
+import com.android.tools.r8.TestDiagnosticMessagesImpl;
 import com.android.tools.r8.TestParameters;
 import com.android.tools.r8.TestParametersCollection;
+import com.android.tools.r8.naming.mappinginformation.MappingInformationDiagnostics;
 import com.android.tools.r8.references.ClassReference;
 import com.android.tools.r8.references.Reference;
 import java.util.Collections;
@@ -44,22 +46,44 @@
           + "  # { id:'com.android.tools.r8.residualsignature',signature:'()Ljava/lang/Object;' }\n"
           + "  int method1() -> a\n"
           + "  # { id:'com.android.tools.r8.residualsignature',signature:'I' }\n"
-          + "  int method2() -> b\n"
+          + "  1:2:int method2():3:4 -> a\n"
+          + "  # { id:'com.android.tools.r8.residualsignature',signature:'Z' }\n"
+          + "  int method3() -> b\n"
           + "  # { id:'com.android.tools.r8.residualsignature',signature:'VOLAPYK' }\n";
 
   @Test
   public void testInvalidResidualMapping() {
-    // TODO(b/267413327): Fail more gracefully than just throwing.
-    assertThrows(
-        AssertionError.class,
-        () ->
-            Retracer.createDefault(
-                    ProguardMapProducer.fromString(mapping), new DiagnosticsHandler() {})
-                .retraceMethod(
-                    Reference.method(
-                        someClassRenamed,
-                        "method1",
-                        Collections.emptyList(),
-                        Reference.primitiveFromDescriptor("I"))));
+    TestDiagnosticMessagesImpl diagnosticsHandler = new TestDiagnosticMessagesImpl();
+    Retracer.createDefault(ProguardMapProducer.fromString(mapping), diagnosticsHandler)
+        .retraceMethod(
+            Reference.method(
+                someClassRenamed,
+                "method1",
+                Collections.emptyList(),
+                Reference.primitiveFromDescriptor("I")));
+    diagnosticsHandler.assertOnlyWarnings();
+    diagnosticsHandler.assertAllWarningsMatch(
+        DiagnosticsMatcher.diagnosticType(MappingInformationDiagnostics.class));
+    diagnosticsHandler.assertWarningsMatch(
+        DiagnosticsMatcher.diagnosticMessage(containsString(getMessage("java.lang.Object a()"))),
+        DiagnosticsMatcher.diagnosticMessage(
+            containsString(
+                getMessage(
+                    "{\"id\":\"com.android.tools.r8.residualsignature\",\"signature\":\"I\"}"))),
+        DiagnosticsMatcher.diagnosticMessage(
+            containsString(
+                getMessage(
+                    "{\"id\":\"com.android.tools.r8.residualsignature\",\"signature\":\"Z\"}"))),
+        DiagnosticsMatcher.diagnosticMessage(
+            containsString(
+                "The residual signature mapping '# {"
+                    + " id:'com.android.tools.r8.residualsignature',signature:'VOLAPYK' }' is"
+                    + " invalid")));
+  }
+
+  private String getMessage(String variable) {
+    return "The residual signature mapping '"
+        + variable
+        + "' is not of the same type as the member it describes.";
   }
 }