diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 219f370fd5..992c609929 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -7030,13 +7030,11 @@ namespace ts {
         function getIntendedTypeFromJSDocTypeReference(node: TypeReferenceNode): Type {
             if (isIdentifier(node.typeName)) {
                 if (node.typeName.escapedText === "Object") {
-                    if (node.typeArguments && node.typeArguments.length === 2) {
+                    if (isJSDocIndexSignature(node)) {
                         const indexed = getTypeFromTypeNode(node.typeArguments[0]);
                         const target = getTypeFromTypeNode(node.typeArguments[1]);
                         const index = createIndexInfo(target, /*isReadonly*/ false);
-                        if (indexed === stringType || indexed === numberType) {
-                            return createAnonymousType(undefined, emptySymbols, emptyArray, emptyArray, indexed === stringType && index, indexed === numberType && index);
-                        }
+                        return createAnonymousType(undefined, emptySymbols, emptyArray, emptyArray, indexed === stringType && index, indexed === numberType && index);
                     }
                     return anyType;
                 }
@@ -7066,6 +7064,14 @@ namespace ts {
             }
         }
 
+        function isJSDocIndexSignature(node: TypeReferenceNode | ExpressionWithTypeArguments) {
+            return isTypeReferenceNode(node) &&
+                isIdentifier(node.typeName) &&
+                node.typeName.escapedText === "Object" &&
+                node.typeArguments && node.typeArguments.length === 2 &&
+                (node.typeArguments[0].kind === SyntaxKind.StringKeyword || node.typeArguments[0].kind === SyntaxKind.NumberKeyword);
+        }
+
         function getTypeFromJSDocNullableTypeNode(node: JSDocNullableType) {
             const type = getTypeFromTypeNode(node.type);
             return strictNullChecks ? getUnionType([type, nullType]) : type;
@@ -19179,7 +19185,10 @@ namespace ts {
                             // There is no resolved symbol cached if the type resolved to a builtin
                             // via JSDoc type reference resolution (eg, Boolean became boolean), none
                             // of which are generic when they have no associated symbol
-                            error(node, Diagnostics.Type_0_is_not_generic, typeToString(type));
+                            // (additionally, JSDoc's index signature syntax, Object<string, T> actually uses generic syntax without being generic)
+                            if (!isJSDocIndexSignature(node)) {
+                                error(node, Diagnostics.Type_0_is_not_generic, typeToString(type));
+                            }
                             return;
                         }
                         let typeParameters = symbol.flags & SymbolFlags.TypeAlias && getSymbolLinks(symbol).typeParameters;
diff --git a/tests/baselines/reference/jsdocIndexSignature.errors.txt b/tests/baselines/reference/jsdocIndexSignature.errors.txt
new file mode 100644
index 0000000000..de336795b3
--- /dev/null
+++ b/tests/baselines/reference/jsdocIndexSignature.errors.txt
@@ -0,0 +1,18 @@
+tests/cases/conformance/jsdoc/indices.js(9,5): error TS2322: Type '1' is not assignable to type 'boolean'.
+
+
+==== tests/cases/conformance/jsdoc/indices.js (1 errors) ====
+    /** @type {Object.<string, number>} */
+    var o1;
+    /** @type {Object.<number, boolean>} */
+    var o2;
+    /** @type {Object.<boolean, string>} */
+    var o3;
+    /** @param {Object.<string, boolean>} o */
+    function f(o) {
+        o.foo = 1; // error
+        ~~~~~
+!!! error TS2322: Type '1' is not assignable to type 'boolean'.
+        o.bar = false; // ok
+    }
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/jsdocIndexSignature.symbols b/tests/baselines/reference/jsdocIndexSignature.symbols
index 8814fc18b6..89288458f4 100644
--- a/tests/baselines/reference/jsdocIndexSignature.symbols
+++ b/tests/baselines/reference/jsdocIndexSignature.symbols
@@ -11,3 +11,15 @@ var o2;
 var o3;
 >o3 : Symbol(o3, Decl(indices.js, 5, 3))
 
+/** @param {Object.<string, boolean>} o */
+function f(o) {
+>f : Symbol(f, Decl(indices.js, 5, 7))
+>o : Symbol(o, Decl(indices.js, 7, 11))
+
+    o.foo = 1; // error
+>o : Symbol(o, Decl(indices.js, 7, 11))
+
+    o.bar = false; // ok
+>o : Symbol(o, Decl(indices.js, 7, 11))
+}
+
diff --git a/tests/baselines/reference/jsdocIndexSignature.types b/tests/baselines/reference/jsdocIndexSignature.types
index 4c1feaa272..d9ac826309 100644
--- a/tests/baselines/reference/jsdocIndexSignature.types
+++ b/tests/baselines/reference/jsdocIndexSignature.types
@@ -11,3 +11,23 @@ var o2;
 var o3;
 >o3 : any
 
+/** @param {Object.<string, boolean>} o */
+function f(o) {
+>f : (o: { [x: string]: boolean; }) => void
+>o : { [x: string]: boolean; }
+
+    o.foo = 1; // error
+>o.foo = 1 : 1
+>o.foo : boolean
+>o : { [x: string]: boolean; }
+>foo : boolean
+>1 : 1
+
+    o.bar = false; // ok
+>o.bar = false : false
+>o.bar : boolean
+>o : { [x: string]: boolean; }
+>bar : boolean
+>false : false
+}
+