diff --git a/.gitignore b/.gitignore
index afd10c0786da9..7da43014e005c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -84,3 +84,4 @@ tests/cases/user/puppeteer/puppeteer
 tests/cases/user/axios-src/axios-src
 tests/cases/user/prettier/prettier
 .eslintcache
+isolate-*-v8.log
\ No newline at end of file
diff --git a/src/compiler/factory/nodeFactory.ts b/src/compiler/factory/nodeFactory.ts
index 713df9c86780a..ab9805908d885 100644
--- a/src/compiler/factory/nodeFactory.ts
+++ b/src/compiler/factory/nodeFactory.ts
@@ -1171,6 +1171,9 @@ namespace ts {
             node.constraint = constraint;
             node.default = defaultType;
             node.transformFlags = TransformFlags.ContainsTypeScript;
+
+            // prevent megamorphism
+            node.expression = undefined;
             return node;
         }
 
@@ -1372,6 +1375,8 @@ namespace ts {
             );
             node.questionToken = questionToken;
             node.transformFlags = TransformFlags.ContainsTypeScript;
+            node.jsDoc = undefined; // added by parser
+            node.jsDocCache = undefined; // added by utilities
             return node;
         }
 
@@ -1438,6 +1443,12 @@ namespace ts {
 
             // The following properties are used only to report grammar errors
             node.exclamationToken = undefined;
+
+            // prevent megamorphism
+            node.jsDoc = undefined; // added by parser
+            node.jsDocCache = undefined; // added by utilities
+            node.flowNode = undefined; // added by binder
+            node.endFlowNode = undefined; // added by binder
             return node;
         }
 
@@ -2363,6 +2374,11 @@ namespace ts {
             node.properties = createNodeArray(properties);
             node.multiLine = multiLine;
             node.transformFlags |= propagateChildrenFlags(node.properties);
+
+            // prevent megamorphism
+            node.symbol = undefined!;
+            node.nextContainer = undefined;
+            (node as JSDocContainer).jsDocCache = undefined;
             return node;
         }
 
@@ -2732,6 +2748,14 @@ namespace ts {
             if (modifiersToFlags(node.modifiers) & ModifierFlags.Async) {
                 node.transformFlags |= TransformFlags.ContainsES2017 | TransformFlags.ContainsLexicalThis;
             }
+
+            // prevent megamorphism
+            node.flowNode = undefined;
+            node.endFlowNode = undefined;
+            node.jsDoc = undefined;
+            node.jsDocCache = undefined;
+            node.contextualType = undefined;
+            node.inferenceContext = undefined;
             return node;
         }
 
@@ -3729,6 +3753,12 @@ namespace ts {
 
             // The following properties are used only to report grammar errors
             node.illegalDecorators = undefined;
+
+            // prevent megamorphism
+            node.jsDoc = undefined; // added by parser
+            node.jsDocCache = undefined; // added by utilities
+            node.endFlowNode = undefined; // added by binder
+
             return node;
         }
 
@@ -5232,11 +5262,13 @@ namespace ts {
                 propagateChildFlags(node.name) |
                 propagateChildFlags(node.initializer);
 
+            node.jsDoc = undefined; // added by parser
+
             // The following properties are used only to report grammar errors
-            node.illegalDecorators = undefined;
-            node.modifiers = undefined;
-            node.questionToken = undefined;
-            node.exclamationToken = undefined;
+            node.illegalDecorators = undefined; // added by parser
+            node.modifiers = undefined; // added by parser
+            node.questionToken = undefined; // added by parser
+            node.exclamationToken = undefined; // added by parser
             return node;
         }