diff --git a/js/src/frontend/BytecodeEmitter.cpp b/js/src/frontend/BytecodeEmitter.cpp
index 283ed249ecf5..09d7b7e2649f 100644
--- a/js/src/frontend/BytecodeEmitter.cpp
+++ b/js/src/frontend/BytecodeEmitter.cpp
@@ -5493,18 +5493,18 @@ BytecodeEmitter::setOrEmitSetFunName(ParseNode* maybeFun, HandleAtom name,
         // Single node can be emitted multiple times if it appears in
         // array destructuring default.  If function already has a name,
         // just return.
-        if (fun->hasCompileTimeName()) {
+        if (fun->hasInferredName()) {
 #ifdef DEBUG
             RootedFunction rootedFun(cx, fun);
             JSAtom* funName = NameToFunctionName(cx, name, prefixKind);
             if (!funName)
                 return false;
-            MOZ_ASSERT(funName == rootedFun->compileTimeName());
+            MOZ_ASSERT(funName == rootedFun->inferredName());
 #endif
             return true;
         }
 
-        fun->setCompileTimeName(name);
+        fun->setInferredName(name);
         return true;
     }
 
diff --git a/js/src/frontend/NameFunctions.cpp b/js/src/frontend/NameFunctions.cpp
index 7e1838682ac3..0faaec9e6930 100644
--- a/js/src/frontend/NameFunctions.cpp
+++ b/js/src/frontend/NameFunctions.cpp
@@ -278,7 +278,11 @@ class NameResolver
         retAtom.set(buf.finishAtom());
         if (!retAtom)
             return false;
-        fun->setGuessedAtom(retAtom);
+
+        // Skip assigning the guessed name if the function has a (dynamically)
+        // computed inferred name.
+        if (!pn->isDirectRHSAnonFunction())
+            fun->setGuessedAtom(retAtom);
         return true;
     }
 
diff --git a/js/src/jit-test/tests/basic/functionnames.js b/js/src/jit-test/tests/basic/functionnames.js
index 7fef872fcefe..6ab440fb410e 100644
--- a/js/src/jit-test/tests/basic/functionnames.js
+++ b/js/src/jit-test/tests/basic/functionnames.js
@@ -130,7 +130,7 @@ assertName(z[0], 'z<');
 odeURIL:(function(){})
 
 a = { 1: function () {} };
-assertName(a[1], 'a[1]');
+assertName(a[1], '1');
 
 a = {
   "embedded spaces": function(){},
diff --git a/js/src/vm/AsyncFunction.cpp b/js/src/vm/AsyncFunction.cpp
index 538d6a211b0a..1ae2bafbe100 100644
--- a/js/src/vm/AsyncFunction.cpp
+++ b/js/src/vm/AsyncFunction.cpp
@@ -138,8 +138,8 @@ js::WrapAsyncFunctionWithProto(JSContext* cx, HandleFunction unwrapped, HandleOb
     if (!wrapped)
         return nullptr;
 
-    if (unwrapped->hasCompileTimeName())
-        wrapped->setCompileTimeName(unwrapped->compileTimeName());
+    if (unwrapped->hasInferredName())
+        wrapped->setInferredName(unwrapped->inferredName());
 
     // Link them to each other to make GetWrappedAsyncFunction and
     // GetUnwrappedAsyncFunction work.
diff --git a/js/src/vm/AsyncIteration.cpp b/js/src/vm/AsyncIteration.cpp
index 2de4cc2139f5..dee53f31bb34 100644
--- a/js/src/vm/AsyncIteration.cpp
+++ b/js/src/vm/AsyncIteration.cpp
@@ -83,8 +83,8 @@ js::WrapAsyncGeneratorWithProto(JSContext* cx, HandleFunction unwrapped, HandleO
     if (!wrapped)
         return nullptr;
 
-    if (unwrapped->hasCompileTimeName())
-        wrapped->setCompileTimeName(unwrapped->compileTimeName());
+    if (unwrapped->hasInferredName())
+        wrapped->setInferredName(unwrapped->inferredName());
 
     // Link them to each other to make GetWrappedAsyncGenerator and
     // GetUnwrappedAsyncGenerator work.
diff --git a/js/src/vm/JSFunction.cpp b/js/src/vm/JSFunction.cpp
index 82ed67440225..0ad1b9abd7c7 100644
--- a/js/src/vm/JSFunction.cpp
+++ b/js/src/vm/JSFunction.cpp
@@ -590,7 +590,7 @@ js::XDRInterpretedFunction(XDRState<mode>* xdr, HandleScope enclosingScope,
         if (!fun->isInterpreted())
             return xdr->fail(JS::TranscodeResult_Failure_NotInterpretedFun);
 
-        if (fun->explicitName() || fun->hasCompileTimeName() || fun->hasGuessedAtom())
+        if (fun->explicitName() || fun->hasInferredName() || fun->hasGuessedAtom())
             firstword |= HasAtom;
 
         if (fun->isGenerator() || fun->isAsync())
@@ -1327,12 +1327,8 @@ JSFunction::getUnresolvedName(JSContext* cx, HandleFunction fun, MutableHandleAt
     MOZ_ASSERT(!IsInternalFunctionObject(*fun));
     MOZ_ASSERT(!fun->hasResolvedName());
 
-    JSAtom* name = fun->explicitOrCompileTimeName();
+    JSAtom* name = fun->explicitOrInferredName();
     if (fun->isClassConstructor()) {
-        // It's impossible to have an empty named class expression. We use
-        // empty as a sentinel when creating default class constructors.
-        MOZ_ASSERT(name != cx->names().empty);
-
         // Unnamed class expressions should not get a .name property at all.
         if (name)
             v.set(name);
@@ -2307,9 +2303,8 @@ js::SetFunctionNameIfNoOwnName(JSContext* cx, HandleFunction fun, HandleValue na
     if (!funNameAtom)
         return false;
 
-    RootedValue funNameVal(cx, StringValue(funNameAtom));
-    if (!NativeDefineDataProperty(cx, fun, cx->names().name, funNameVal, JSPROP_READONLY))
-        return false;
+    MOZ_ASSERT(!fun->hasResolvedName());
+    fun->setInferredName(funNameAtom);
 
     return true;
 }
diff --git a/js/src/vm/JSFunction.h b/js/src/vm/JSFunction.h
index 71723d1ff0a9..11819a0232c7 100644
--- a/js/src/vm/JSFunction.h
+++ b/js/src/vm/JSFunction.h
@@ -70,9 +70,9 @@ class JSFunction : public js::NativeObject
                                        function-statement) */
         SELF_HOSTED      = 0x0080,  /* function is self-hosted builtin and must not be
                                        decompilable nor constructible. */
-        HAS_COMPILE_TIME_NAME = 0x0100, /* function had no explicit name, but a
-                                           name was set by SetFunctionName
-                                           at compile time */
+        HAS_INFERRED_NAME = 0x0100, /* function had no explicit name, but a name was
+                                       set by SetFunctionName at compile time or
+                                       SetFunctionNameIfNoOwnName at runtime. */
         INTERPRETED_LAZY = 0x0200,  /* function is interpreted but doesn't have a script yet */
         RESOLVED_LENGTH  = 0x0400,  /* f.length has been resolved (see fun_resolve). */
         RESOLVED_NAME    = 0x0800,  /* f.name has been resolved (see fun_resolve). */
@@ -106,8 +106,7 @@ class JSFunction : public js::NativeObject
         INTERPRETED_GENERATOR_OR_ASYNC = INTERPRETED,
         NO_XDR_FLAGS = RESOLVED_LENGTH | RESOLVED_NAME,
 
-        STABLE_ACROSS_CLONES = CONSTRUCTOR | LAMBDA | SELF_HOSTED | HAS_COMPILE_TIME_NAME |
-                               FUNCTION_KIND_MASK
+        STABLE_ACROSS_CLONES = CONSTRUCTOR | LAMBDA | SELF_HOSTED | FUNCTION_KIND_MASK
     };
 
     static_assert((INTERPRETED | INTERPRETED_LAZY) == js::JS_FUNCTION_INTERPRETED_BITS,
@@ -205,7 +204,7 @@ class JSFunction : public js::NativeObject
 
     /* Possible attributes of an interpreted function: */
     bool isBoundFunction()          const { return flags() & BOUND_FUN; }
-    bool hasCompileTimeName()       const { return flags() & HAS_COMPILE_TIME_NAME; }
+    bool hasInferredName()          const { return flags() & HAS_INFERRED_NAME; }
     bool hasGuessedAtom()           const {
         static_assert(HAS_GUESSED_ATOM == HAS_BOUND_FUNCTION_NAME_PREFIX,
                       "HAS_GUESSED_ATOM is unused for bound functions");
@@ -259,7 +258,7 @@ class JSFunction : public js::NativeObject
     }
 
     bool isNamedLambda() const {
-        return isLambda() && displayAtom() && !hasCompileTimeName() && !hasGuessedAtom();
+        return isLambda() && displayAtom() && !hasInferredName() && !hasGuessedAtom();
     }
 
     bool hasLexicalThis() const {
@@ -346,9 +345,9 @@ class JSFunction : public js::NativeObject
                                   js::MutableHandleAtom v);
 
     JSAtom* explicitName() const {
-        return (hasCompileTimeName() || hasGuessedAtom()) ? nullptr : atom_.get();
+        return (hasInferredName() || hasGuessedAtom()) ? nullptr : atom_.get();
     }
-    JSAtom* explicitOrCompileTimeName() const {
+    JSAtom* explicitOrInferredName() const {
         return hasGuessedAtom() ? nullptr : atom_.get();
     }
 
@@ -366,16 +365,21 @@ class JSFunction : public js::NativeObject
         return atom_;
     }
 
-    void setCompileTimeName(JSAtom* atom) {
+    void setInferredName(JSAtom* atom) {
         MOZ_ASSERT(!atom_);
         MOZ_ASSERT(atom);
         MOZ_ASSERT(!hasGuessedAtom());
-        MOZ_ASSERT(!isClassConstructor());
         setAtom(atom);
-        flags_ |= HAS_COMPILE_TIME_NAME;
+        flags_ |= HAS_INFERRED_NAME;
     }
-    JSAtom* compileTimeName() const {
-        MOZ_ASSERT(hasCompileTimeName());
+    void clearInferredName() {
+        MOZ_ASSERT(hasInferredName());
+        MOZ_ASSERT(atom_);
+        setAtom(nullptr);
+        flags_ &= ~HAS_INFERRED_NAME;
+    }
+    JSAtom* inferredName() const {
+        MOZ_ASSERT(hasInferredName());
         MOZ_ASSERT(atom_);
         return atom_;
     }
@@ -383,7 +387,7 @@ class JSFunction : public js::NativeObject
     void setGuessedAtom(JSAtom* atom) {
         MOZ_ASSERT(!atom_);
         MOZ_ASSERT(atom);
-        MOZ_ASSERT(!hasCompileTimeName());
+        MOZ_ASSERT(!hasInferredName());
         MOZ_ASSERT(!hasGuessedAtom());
         MOZ_ASSERT(!isBoundFunction());
         setAtom(atom);
diff --git a/js/src/vm/SelfHosting.cpp b/js/src/vm/SelfHosting.cpp
index 0f55d8e95d6d..79b7ca724fbb 100644
--- a/js/src/vm/SelfHosting.cpp
+++ b/js/src/vm/SelfHosting.cpp
@@ -480,10 +480,10 @@ intrinsic_MakeDefaultConstructor(JSContext* cx, unsigned argc, Value* vp)
 
     // Because self-hosting code does not allow top-level lexicals,
     // class constructors are class expressions in top-level vars.
-    // Because of this, we give them a guessed atom. Since they
+    // Because of this, we give them an inferred atom. Since they
     // will always be cloned, and given an explicit atom, instead
     // overrule that.
-    ctor->clearGuessedAtom();
+    ctor->clearInferredName();
 
     args.rval().setUndefined();
     return true;