diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index a3808fd56e21a..20d075cdfc07f 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -23665,7 +23665,7 @@ namespace ts {
             }
             if (isEntityNameExpression(node.argumentExpression)) {
                 const symbol = resolveEntityName(node.argumentExpression, SymbolFlags.Value, /*ignoreErrors*/ true);
-                if (!symbol || !isConstVariable(symbol)) return undefined;
+                if (!symbol || !(isConstVariable(symbol) || (symbol.flags & SymbolFlags.EnumMember))) return undefined;
 
                 const declaration = symbol.valueDeclaration;
                 if (declaration === undefined) return undefined;
@@ -23680,7 +23680,12 @@ namespace ts {
 
                 if (hasOnlyExpressionInitializer(declaration) && isBlockScopedNameDeclaredBeforeUse(declaration, node.argumentExpression)) {
                     const initializer = getEffectiveInitializer(declaration);
-                    return initializer && tryGetNameFromType(getTypeOfExpression(initializer));
+                    if (initializer) {
+                        return tryGetNameFromType(getTypeOfExpression(initializer));
+                    }
+                    if (isEnumMember(declaration)) {
+                        return getTextOfPropertyName(declaration.name);
+                    }
                 }
             }
             return undefined;
diff --git a/tests/baselines/reference/strictPropertyInitialization.errors.txt b/tests/baselines/reference/strictPropertyInitialization.errors.txt
index 208c0a32e4d1d..7e3a834b84f40 100644
--- a/tests/baselines/reference/strictPropertyInitialization.errors.txt
+++ b/tests/baselines/reference/strictPropertyInitialization.errors.txt
@@ -179,4 +179,15 @@ tests/cases/conformance/classes/propertyMemberDeclarations/strictPropertyInitial
             this['c'] = 1;
         }
     }
+    
+    enum E {
+        A = "A",
+        B = "B"
+    }
+    class C13 {
+        [E.A]: number;
+        constructor() {
+            this[E.A] = 1;
+        }
+    }
     
\ No newline at end of file
diff --git a/tests/baselines/reference/strictPropertyInitialization.js b/tests/baselines/reference/strictPropertyInitialization.js
index 41760958edd1f..43411f15ad837 100644
--- a/tests/baselines/reference/strictPropertyInitialization.js
+++ b/tests/baselines/reference/strictPropertyInitialization.js
@@ -147,6 +147,17 @@ class C12 {
         this['c'] = 1;
     }
 }
+
+enum E {
+    A = "A",
+    B = "B"
+}
+class C13 {
+    [E.A]: number;
+    constructor() {
+        this[E.A] = 1;
+    }
+}
 
 
 //// [strictPropertyInitialization.js]
@@ -259,6 +270,17 @@ class C12 {
         this['c'] = 1;
     }
 }
+var E;
+(function (E) {
+    E["A"] = "A";
+    E["B"] = "B";
+})(E || (E = {}));
+class C13 {
+    constructor() {
+        this[E.A] = 1;
+    }
+}
+E.A;
 
 
 //// [strictPropertyInitialization.d.ts]
@@ -335,3 +357,11 @@ declare class C12 {
     ['c']: number;
     constructor();
 }
+declare enum E {
+    A = "A",
+    B = "B"
+}
+declare class C13 {
+    [E.A]: number;
+    constructor();
+}
diff --git a/tests/baselines/reference/strictPropertyInitialization.symbols b/tests/baselines/reference/strictPropertyInitialization.symbols
index 45e15f21403e5..3b81ef3d31835 100644
--- a/tests/baselines/reference/strictPropertyInitialization.symbols
+++ b/tests/baselines/reference/strictPropertyInitialization.symbols
@@ -348,3 +348,30 @@ class C12 {
     }
 }
 
+enum E {
+>E : Symbol(E, Decl(strictPropertyInitialization.ts, 147, 1))
+
+    A = "A",
+>A : Symbol(E.A, Decl(strictPropertyInitialization.ts, 149, 8))
+
+    B = "B"
+>B : Symbol(E.B, Decl(strictPropertyInitialization.ts, 150, 12))
+}
+class C13 {
+>C13 : Symbol(C13, Decl(strictPropertyInitialization.ts, 152, 1))
+
+    [E.A]: number;
+>[E.A] : Symbol(C13[E.A], Decl(strictPropertyInitialization.ts, 153, 11))
+>E.A : Symbol(E.A, Decl(strictPropertyInitialization.ts, 149, 8))
+>E : Symbol(E, Decl(strictPropertyInitialization.ts, 147, 1))
+>A : Symbol(E.A, Decl(strictPropertyInitialization.ts, 149, 8))
+
+    constructor() {
+        this[E.A] = 1;
+>this : Symbol(C13, Decl(strictPropertyInitialization.ts, 152, 1))
+>E.A : Symbol(E.A, Decl(strictPropertyInitialization.ts, 149, 8))
+>E : Symbol(E, Decl(strictPropertyInitialization.ts, 147, 1))
+>A : Symbol(E.A, Decl(strictPropertyInitialization.ts, 149, 8))
+    }
+}
+
diff --git a/tests/baselines/reference/strictPropertyInitialization.types b/tests/baselines/reference/strictPropertyInitialization.types
index 84d375c85157a..616e41d9be324 100644
--- a/tests/baselines/reference/strictPropertyInitialization.types
+++ b/tests/baselines/reference/strictPropertyInitialization.types
@@ -395,3 +395,35 @@ class C12 {
     }
 }
 
+enum E {
+>E : E
+
+    A = "A",
+>A : E.A
+>"A" : "A"
+
+    B = "B"
+>B : E.B
+>"B" : "B"
+}
+class C13 {
+>C13 : C13
+
+    [E.A]: number;
+>[E.A] : number
+>E.A : E.A
+>E : typeof E
+>A : E.A
+
+    constructor() {
+        this[E.A] = 1;
+>this[E.A] = 1 : 1
+>this[E.A] : number
+>this : this
+>E.A : E.A
+>E : typeof E
+>A : E.A
+>1 : 1
+    }
+}
+
diff --git a/tests/baselines/reference/typeGuardNarrowsIndexedAccessOfKnownProperty11.js b/tests/baselines/reference/typeGuardNarrowsIndexedAccessOfKnownProperty11.js
new file mode 100644
index 0000000000000..64d1df74a81f2
--- /dev/null
+++ b/tests/baselines/reference/typeGuardNarrowsIndexedAccessOfKnownProperty11.js
@@ -0,0 +1,20 @@
+//// [typeGuardNarrowsIndexedAccessOfKnownProperty11.ts]
+enum E { A, B }
+
+declare const m: { [K in E]: string | null };
+
+if (m[E.A] !== null) {
+    m[E.A].toString(); // string
+}
+
+
+//// [typeGuardNarrowsIndexedAccessOfKnownProperty11.js]
+"use strict";
+var E;
+(function (E) {
+    E[E["A"] = 0] = "A";
+    E[E["B"] = 1] = "B";
+})(E || (E = {}));
+if (m[E.A] !== null) {
+    m[E.A].toString(); // string
+}
diff --git a/tests/baselines/reference/typeGuardNarrowsIndexedAccessOfKnownProperty11.symbols b/tests/baselines/reference/typeGuardNarrowsIndexedAccessOfKnownProperty11.symbols
new file mode 100644
index 0000000000000..f97e136634ab3
--- /dev/null
+++ b/tests/baselines/reference/typeGuardNarrowsIndexedAccessOfKnownProperty11.symbols
@@ -0,0 +1,26 @@
+=== tests/cases/compiler/typeGuardNarrowsIndexedAccessOfKnownProperty11.ts ===
+enum E { A, B }
+>E : Symbol(E, Decl(typeGuardNarrowsIndexedAccessOfKnownProperty11.ts, 0, 0))
+>A : Symbol(E.A, Decl(typeGuardNarrowsIndexedAccessOfKnownProperty11.ts, 0, 8))
+>B : Symbol(E.B, Decl(typeGuardNarrowsIndexedAccessOfKnownProperty11.ts, 0, 11))
+
+declare const m: { [K in E]: string | null };
+>m : Symbol(m, Decl(typeGuardNarrowsIndexedAccessOfKnownProperty11.ts, 2, 13))
+>K : Symbol(K, Decl(typeGuardNarrowsIndexedAccessOfKnownProperty11.ts, 2, 20))
+>E : Symbol(E, Decl(typeGuardNarrowsIndexedAccessOfKnownProperty11.ts, 0, 0))
+
+if (m[E.A] !== null) {
+>m : Symbol(m, Decl(typeGuardNarrowsIndexedAccessOfKnownProperty11.ts, 2, 13))
+>E.A : Symbol(E.A, Decl(typeGuardNarrowsIndexedAccessOfKnownProperty11.ts, 0, 8))
+>E : Symbol(E, Decl(typeGuardNarrowsIndexedAccessOfKnownProperty11.ts, 0, 0))
+>A : Symbol(E.A, Decl(typeGuardNarrowsIndexedAccessOfKnownProperty11.ts, 0, 8))
+
+    m[E.A].toString(); // string
+>m[E.A].toString : Symbol(String.toString, Decl(lib.es5.d.ts, --, --))
+>m : Symbol(m, Decl(typeGuardNarrowsIndexedAccessOfKnownProperty11.ts, 2, 13))
+>E.A : Symbol(E.A, Decl(typeGuardNarrowsIndexedAccessOfKnownProperty11.ts, 0, 8))
+>E : Symbol(E, Decl(typeGuardNarrowsIndexedAccessOfKnownProperty11.ts, 0, 0))
+>A : Symbol(E.A, Decl(typeGuardNarrowsIndexedAccessOfKnownProperty11.ts, 0, 8))
+>toString : Symbol(String.toString, Decl(lib.es5.d.ts, --, --))
+}
+
diff --git a/tests/baselines/reference/typeGuardNarrowsIndexedAccessOfKnownProperty11.types b/tests/baselines/reference/typeGuardNarrowsIndexedAccessOfKnownProperty11.types
new file mode 100644
index 0000000000000..c9ca26e0116d2
--- /dev/null
+++ b/tests/baselines/reference/typeGuardNarrowsIndexedAccessOfKnownProperty11.types
@@ -0,0 +1,30 @@
+=== tests/cases/compiler/typeGuardNarrowsIndexedAccessOfKnownProperty11.ts ===
+enum E { A, B }
+>E : E
+>A : E.A
+>B : E.B
+
+declare const m: { [K in E]: string | null };
+>m : { 0: string | null; 1: string | null; }
+>null : null
+
+if (m[E.A] !== null) {
+>m[E.A] !== null : boolean
+>m[E.A] : string | null
+>m : { 0: string | null; 1: string | null; }
+>E.A : E.A
+>E : typeof E
+>A : E.A
+>null : null
+
+    m[E.A].toString(); // string
+>m[E.A].toString() : string
+>m[E.A].toString : () => string
+>m[E.A] : string
+>m : { 0: string | null; 1: string | null; }
+>E.A : E.A
+>E : typeof E
+>A : E.A
+>toString : () => string
+}
+
diff --git a/tests/baselines/reference/typeGuardNarrowsIndexedAccessOfKnownProperty12.js b/tests/baselines/reference/typeGuardNarrowsIndexedAccessOfKnownProperty12.js
new file mode 100644
index 0000000000000..0f6a6be2243b6
--- /dev/null
+++ b/tests/baselines/reference/typeGuardNarrowsIndexedAccessOfKnownProperty12.js
@@ -0,0 +1,23 @@
+//// [typeGuardNarrowsIndexedAccessOfKnownProperty12.ts]
+enum E {
+    A = "A",
+    B = "B"
+}
+
+declare const m: { [K in E]: string | null };
+
+if (m[E.A] !== null) {
+    m[E.A].toString(); // string
+}
+
+
+//// [typeGuardNarrowsIndexedAccessOfKnownProperty12.js]
+"use strict";
+var E;
+(function (E) {
+    E["A"] = "A";
+    E["B"] = "B";
+})(E || (E = {}));
+if (m[E.A] !== null) {
+    m[E.A].toString(); // string
+}
diff --git a/tests/baselines/reference/typeGuardNarrowsIndexedAccessOfKnownProperty12.symbols b/tests/baselines/reference/typeGuardNarrowsIndexedAccessOfKnownProperty12.symbols
new file mode 100644
index 0000000000000..3b4e17f6df88d
--- /dev/null
+++ b/tests/baselines/reference/typeGuardNarrowsIndexedAccessOfKnownProperty12.symbols
@@ -0,0 +1,31 @@
+=== tests/cases/compiler/typeGuardNarrowsIndexedAccessOfKnownProperty12.ts ===
+enum E {
+>E : Symbol(E, Decl(typeGuardNarrowsIndexedAccessOfKnownProperty12.ts, 0, 0))
+
+    A = "A",
+>A : Symbol(E.A, Decl(typeGuardNarrowsIndexedAccessOfKnownProperty12.ts, 0, 8))
+
+    B = "B"
+>B : Symbol(E.B, Decl(typeGuardNarrowsIndexedAccessOfKnownProperty12.ts, 1, 12))
+}
+
+declare const m: { [K in E]: string | null };
+>m : Symbol(m, Decl(typeGuardNarrowsIndexedAccessOfKnownProperty12.ts, 5, 13))
+>K : Symbol(K, Decl(typeGuardNarrowsIndexedAccessOfKnownProperty12.ts, 5, 20))
+>E : Symbol(E, Decl(typeGuardNarrowsIndexedAccessOfKnownProperty12.ts, 0, 0))
+
+if (m[E.A] !== null) {
+>m : Symbol(m, Decl(typeGuardNarrowsIndexedAccessOfKnownProperty12.ts, 5, 13))
+>E.A : Symbol(E.A, Decl(typeGuardNarrowsIndexedAccessOfKnownProperty12.ts, 0, 8))
+>E : Symbol(E, Decl(typeGuardNarrowsIndexedAccessOfKnownProperty12.ts, 0, 0))
+>A : Symbol(E.A, Decl(typeGuardNarrowsIndexedAccessOfKnownProperty12.ts, 0, 8))
+
+    m[E.A].toString(); // string
+>m[E.A].toString : Symbol(String.toString, Decl(lib.es5.d.ts, --, --))
+>m : Symbol(m, Decl(typeGuardNarrowsIndexedAccessOfKnownProperty12.ts, 5, 13))
+>E.A : Symbol(E.A, Decl(typeGuardNarrowsIndexedAccessOfKnownProperty12.ts, 0, 8))
+>E : Symbol(E, Decl(typeGuardNarrowsIndexedAccessOfKnownProperty12.ts, 0, 0))
+>A : Symbol(E.A, Decl(typeGuardNarrowsIndexedAccessOfKnownProperty12.ts, 0, 8))
+>toString : Symbol(String.toString, Decl(lib.es5.d.ts, --, --))
+}
+
diff --git a/tests/baselines/reference/typeGuardNarrowsIndexedAccessOfKnownProperty12.types b/tests/baselines/reference/typeGuardNarrowsIndexedAccessOfKnownProperty12.types
new file mode 100644
index 0000000000000..37d173c304d23
--- /dev/null
+++ b/tests/baselines/reference/typeGuardNarrowsIndexedAccessOfKnownProperty12.types
@@ -0,0 +1,37 @@
+=== tests/cases/compiler/typeGuardNarrowsIndexedAccessOfKnownProperty12.ts ===
+enum E {
+>E : E
+
+    A = "A",
+>A : E.A
+>"A" : "A"
+
+    B = "B"
+>B : E.B
+>"B" : "B"
+}
+
+declare const m: { [K in E]: string | null };
+>m : { A: string | null; B: string | null; }
+>null : null
+
+if (m[E.A] !== null) {
+>m[E.A] !== null : boolean
+>m[E.A] : string | null
+>m : { A: string | null; B: string | null; }
+>E.A : E.A
+>E : typeof E
+>A : E.A
+>null : null
+
+    m[E.A].toString(); // string
+>m[E.A].toString() : string
+>m[E.A].toString : () => string
+>m[E.A] : string
+>m : { A: string | null; B: string | null; }
+>E.A : E.A
+>E : typeof E
+>A : E.A
+>toString : () => string
+}
+
diff --git a/tests/cases/compiler/typeGuardNarrowsIndexedAccessOfKnownProperty11.ts b/tests/cases/compiler/typeGuardNarrowsIndexedAccessOfKnownProperty11.ts
new file mode 100644
index 0000000000000..acf01af8cd03b
--- /dev/null
+++ b/tests/cases/compiler/typeGuardNarrowsIndexedAccessOfKnownProperty11.ts
@@ -0,0 +1,9 @@
+// @strict: true
+
+enum E { A, B }
+
+declare const m: { [K in E]: string | null };
+
+if (m[E.A] !== null) {
+    m[E.A].toString(); // string
+}
diff --git a/tests/cases/compiler/typeGuardNarrowsIndexedAccessOfKnownProperty12.ts b/tests/cases/compiler/typeGuardNarrowsIndexedAccessOfKnownProperty12.ts
new file mode 100644
index 0000000000000..e426161f08fa0
--- /dev/null
+++ b/tests/cases/compiler/typeGuardNarrowsIndexedAccessOfKnownProperty12.ts
@@ -0,0 +1,12 @@
+// @strict: true
+
+enum E {
+    A = "A",
+    B = "B"
+}
+
+declare const m: { [K in E]: string | null };
+
+if (m[E.A] !== null) {
+    m[E.A].toString(); // string
+}
diff --git a/tests/cases/conformance/classes/propertyMemberDeclarations/strictPropertyInitialization.ts b/tests/cases/conformance/classes/propertyMemberDeclarations/strictPropertyInitialization.ts
index 3caf731626494..74831b2a730ef 100644
--- a/tests/cases/conformance/classes/propertyMemberDeclarations/strictPropertyInitialization.ts
+++ b/tests/cases/conformance/classes/propertyMemberDeclarations/strictPropertyInitialization.ts
@@ -150,3 +150,14 @@ class C12 {
         this['c'] = 1;
     }
 }
+
+enum E {
+    A = "A",
+    B = "B"
+}
+class C13 {
+    [E.A]: number;
+    constructor() {
+        this[E.A] = 1;
+    }
+}