diff --git a/src/ir/possible-contents.cpp b/src/ir/possible-contents.cpp
index 24e42cf1c42..f07a42acf97 100644
--- a/src/ir/possible-contents.cpp
+++ b/src/ir/possible-contents.cpp
@@ -2243,7 +2243,11 @@ struct Flower {
   // For a non-full cone, we also reduce the depth as much as possible, so it is
   // equal to the maximum depth of an existing subtype.
   Index getNormalizedConeDepth(Type type, Index depth) {
-    return std::min(depth, maxDepths[type.getHeapType()]);
+    auto iter = maxDepths.find(type.getHeapType());
+    // A max depth must be in the map (otherwise we would use the default 0,
+    // making it exact, almost certainly incorrectly).
+    assert(iter != maxDepths.end());
+    return std::min(depth, iter->second);
   }
 
   void normalizeConeType(PossibleContents& cone) {
@@ -2639,6 +2643,12 @@ bool Flower::updateContents(LocationIndex locationIndex,
     // more later (we compute that at the end), so use a temp out var for that.
     bool worthSendingMoreTemp = true;
     filterExpressionContents(newContents, *exprLoc, worthSendingMoreTemp);
+
+#if defined(POSSIBLE_CONTENTS_DEBUG) && POSSIBLE_CONTENTS_DEBUG >= 2
+    std::cout << "  post-filtered exprLoc:\n";
+    newContents.dump(std::cout, &wasm);
+    std::cout << '\n';
+#endif
   } else if (auto* globalLoc = std::get_if<GlobalLocation>(&location)) {
     // Generic filtering. We do this both before and after.
     filterGlobalContents(newContents, *globalLoc);
diff --git a/src/ir/subtypes.h b/src/ir/subtypes.h
index 5c654ceb7be..fa949e992c2 100644
--- a/src/ir/subtypes.h
+++ b/src/ir/subtypes.h
@@ -135,6 +135,7 @@ struct SubTypes {
       basicDepth = std::max(basicDepth, depths[type] + 1);
     }
 
+    // Fill in the other basic types.
     for (auto share : {Unshared, Shared}) {
       depths[HeapTypes::eq.getBasic(share)] =
         std::max(depths[HeapTypes::struct_.getBasic(share)],
@@ -142,6 +143,19 @@ struct SubTypes {
         1;
       depths[HeapTypes::any.getBasic(share)] =
         depths[HeapTypes::eq.getBasic(share)] + 1;
+
+      depths[HeapTypes::i31.getBasic(share)] = 0;
+      depths[HeapTypes::exn.getBasic(share)] = 0;
+
+      // Extern has string as a subtype.
+      depths[HeapTypes::ext.getBasic(share)] = 1;
+      depths[HeapTypes::string.getBasic(share)] = 0;
+
+      depths[HeapTypes::none.getBasic(share)] = 0;
+      depths[HeapTypes::noext.getBasic(share)] = 0;
+      depths[HeapTypes::nofunc.getBasic(share)] = 0;
+      depths[HeapTypes::nocont.getBasic(share)] = 0;
+      depths[HeapTypes::noexn.getBasic(share)] = 0;
     }
 
     return depths;
diff --git a/test/gtest/type-builder.cpp b/test/gtest/type-builder.cpp
index da7f4c60f7c..d7ad960b185 100644
--- a/test/gtest/type-builder.cpp
+++ b/test/gtest/type-builder.cpp
@@ -1604,6 +1604,15 @@ TEST_F(TypeTest, TestMaxStructDepths) {
   EXPECT_EQ(maxDepths[HeapType::struct_], Index(2));
   EXPECT_EQ(maxDepths[HeapType::eq], Index(3));
   EXPECT_EQ(maxDepths[HeapType::any], Index(4));
+  EXPECT_EQ(maxDepths[HeapType::i31], Index(0));
+  EXPECT_EQ(maxDepths[HeapType::exn], Index(0));
+  EXPECT_EQ(maxDepths[HeapType::ext], Index(1));
+  EXPECT_EQ(maxDepths[HeapType::string], Index(0));
+  EXPECT_EQ(maxDepths[HeapType::none], Index(0));
+  EXPECT_EQ(maxDepths[HeapType::noext], Index(0));
+  EXPECT_EQ(maxDepths[HeapType::nofunc], Index(0));
+  EXPECT_EQ(maxDepths[HeapType::nocont], Index(0));
+  EXPECT_EQ(maxDepths[HeapType::noexn], Index(0));
 }
 
 TEST_F(TypeTest, TestMaxArrayDepths) {