diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 9b66295a663ed..cbfc028ccb881 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -468,7 +468,29 @@ namespace ts {
             getRootSymbols,
             getContextualType: (nodeIn: Expression, contextFlags?: ContextFlags) => {
                 const node = getParseTreeNode(nodeIn, isExpression);
-                return node ? getContextualType(node, contextFlags) : undefined;
+                if (!node) {
+                    return undefined;
+                }
+                const containingCall = findAncestor(node, isCallLikeExpression);
+                const containingCallResolvedSignature = containingCall && getNodeLinks(containingCall).resolvedSignature;
+                if (contextFlags! & ContextFlags.BaseConstraint && containingCall) {
+                    let toMarkSkip = node as Node;
+                    do {
+                        getNodeLinks(toMarkSkip).skipDirectInference = true;
+                        toMarkSkip = toMarkSkip.parent;
+                    } while (toMarkSkip && toMarkSkip !== containingCall);
+                    getNodeLinks(containingCall).resolvedSignature = undefined;
+                }
+                const result = getContextualType(node, contextFlags);
+                if (contextFlags! & ContextFlags.BaseConstraint && containingCall) {
+                    let toMarkSkip = node as Node;
+                    do {
+                        getNodeLinks(toMarkSkip).skipDirectInference = undefined;
+                        toMarkSkip = toMarkSkip.parent;
+                    } while (toMarkSkip && toMarkSkip !== containingCall);
+                    getNodeLinks(containingCall).resolvedSignature = containingCallResolvedSignature;
+                }
+                return result;
             },
             getContextualTypeForObjectLiteralElement: nodeIn => {
                 const node = getParseTreeNode(nodeIn, isObjectLiteralElementLike);
@@ -17797,6 +17819,14 @@ namespace ts {
                 undefined;
         }
 
+        function hasSkipDirectInferenceFlag(node: Node) {
+            return !!getNodeLinks(node).skipDirectInference;
+        }
+
+        function isFromInferenceBlockedSource(type: Type) {
+            return !!(type.symbol && some(type.symbol.declarations, hasSkipDirectInferenceFlag));
+        }
+
         function inferTypes(inferences: InferenceInfo[], originalSource: Type, originalTarget: Type, priority: InferencePriority = 0, contravariant = false) {
             let symbolStack: Symbol[];
             let visited: Map<number>;
@@ -17887,7 +17917,7 @@ namespace ts {
                     // of inference. Also, we exclude inferences for silentNeverType (which is used as a wildcard
                     // when constructing types from type parameters that had no inference candidates).
                     if (getObjectFlags(source) & ObjectFlags.NonInferrableType || source === nonInferrableAnyType || source === silentNeverType ||
-                        (priority & InferencePriority.ReturnType && (source === autoType || source === autoArrayType))) {
+                        (priority & InferencePriority.ReturnType && (source === autoType || source === autoArrayType)) || isFromInferenceBlockedSource(source)) {
                         return;
                     }
                     const inference = getInferenceInfoForType(target);
@@ -18191,7 +18221,7 @@ namespace ts {
                     // type and then make a secondary inference from that type to T. We make a secondary inference
                     // such that direct inferences to T get priority over inferences to Partial<T>, for example.
                     const inference = getInferenceInfoForType((<IndexType>constraintType).type);
-                    if (inference && !inference.isFixed) {
+                    if (inference && !inference.isFixed && !isFromInferenceBlockedSource(source)) {
                         const inferredType = inferTypeForHomomorphicMappedType(source, target, <IndexType>constraintType);
                         if (inferredType) {
                             // We assign a lower priority to inferences made from types containing non-inferrable
@@ -21450,19 +21480,16 @@ namespace ts {
         }
 
         // In a typed function call, an argument or substitution expression is contextually typed by the type of the corresponding parameter.
-        function getContextualTypeForArgument(callTarget: CallLikeExpression, arg: Expression, contextFlags?: ContextFlags): Type | undefined {
+        function getContextualTypeForArgument(callTarget: CallLikeExpression, arg: Expression): Type | undefined {
             const args = getEffectiveCallArguments(callTarget);
             const argIndex = args.indexOf(arg); // -1 for e.g. the expression of a CallExpression, or the tag of a TaggedTemplateExpression
-            return argIndex === -1 ? undefined : getContextualTypeForArgumentAtIndex(callTarget, argIndex, contextFlags);
+            return argIndex === -1 ? undefined : getContextualTypeForArgumentAtIndex(callTarget, argIndex);
         }
 
-        function getContextualTypeForArgumentAtIndex(callTarget: CallLikeExpression, argIndex: number, contextFlags?: ContextFlags): Type {
+        function getContextualTypeForArgumentAtIndex(callTarget: CallLikeExpression, argIndex: number): Type {
             // If we're already in the process of resolving the given signature, don't resolve again as
             // that could cause infinite recursion. Instead, return anySignature.
-            let signature = getNodeLinks(callTarget).resolvedSignature === resolvingSignature ? resolvingSignature : getResolvedSignature(callTarget);
-            if (contextFlags && contextFlags & ContextFlags.BaseConstraint && signature.target && !hasTypeArguments(callTarget)) {
-                signature = getBaseSignature(signature.target);
-            }
+            const signature = getNodeLinks(callTarget).resolvedSignature === resolvingSignature ? resolvingSignature : getResolvedSignature(callTarget);
 
             if (isJsxOpeningLikeElement(callTarget) && argIndex === 0) {
                 return getEffectiveFirstArgumentForJsxSignature(signature, callTarget);
@@ -21858,7 +21885,7 @@ namespace ts {
                     }
                     /* falls through */
                 case SyntaxKind.NewExpression:
-                    return getContextualTypeForArgument(<CallExpression | NewExpression>parent, node, contextFlags);
+                    return getContextualTypeForArgument(<CallExpression | NewExpression>parent, node);
                 case SyntaxKind.TypeAssertionExpression:
                 case SyntaxKind.AsExpression:
                     return isConstTypeReference((<AssertionExpression>parent).type) ? undefined : getTypeFromTypeNode((<AssertionExpression>parent).type);
@@ -21908,7 +21935,7 @@ namespace ts {
                 // (as below) instead!
                 return node.parent.contextualType;
             }
-            return getContextualTypeForArgumentAtIndex(node, 0, contextFlags);
+            return getContextualTypeForArgumentAtIndex(node, 0);
         }
 
         function getEffectiveFirstArgumentForJsxSignature(signature: Signature, node: JsxOpeningLikeElement) {
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index b5760f7a88e8e..1191d541a1546 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -4249,6 +4249,7 @@ namespace ts {
         outerTypeParameters?: TypeParameter[];  // Outer type parameters of anonymous object type
         instantiations?: Map<Type>;         // Instantiations of generic type alias (undefined if non-generic)
         isExhaustive?: boolean;           // Is node an exhaustive switch statement
+        skipDirectInference?: true;         // Flag set by the API `getContextualType` call on a node when `BaseConstraint` is passed to force the checker to skip making inferences to a node's type
     }
 
     export const enum TypeFlags {
diff --git a/tests/cases/fourslash/completionsObjectLiteralWithPartialConstraint.ts b/tests/cases/fourslash/completionsObjectLiteralWithPartialConstraint.ts
new file mode 100644
index 0000000000000..ebd47f3d9a995
--- /dev/null
+++ b/tests/cases/fourslash/completionsObjectLiteralWithPartialConstraint.ts
@@ -0,0 +1,64 @@
+/// <reference path="fourslash.ts" />
+
+////interface MyOptions {
+////    hello?: boolean;
+////    world?: boolean;
+////}
+////declare function bar<T extends MyOptions>(options?: Partial<T>): void;
+////bar({ hello: true, /*1*/ });
+////
+////interface Test {
+////    keyPath?: string;
+////    autoIncrement?: boolean;
+////}
+////
+////function test<T extends Record<string, Test>>(opt: T) { }
+////
+////test({
+////    a: {
+////        keyPath: 'x.y',
+////        autoIncrement: true
+////    },
+////    b: {
+////        /*2*/
+////    }
+////});
+////type Colors = {
+////    rgb: { r: number, g: number, b: number };
+////    hsl: { h: number, s: number, l: number }
+////};
+////
+////function createColor<T extends keyof Colors>(kind: T, values: Colors[T]) { }
+////
+////createColor('rgb', {
+////  /*3*/
+////});
+////
+////declare function f<T extends 'a' | 'b', U extends { a?: string }, V extends { b?: string }>(x: T, y: { a: U, b: V }[T]): void;
+////
+////f('a', {
+////  /*4*/
+////});
+////
+////declare function f2<T extends { x?: string }>(x: T): void;
+////f2({
+////  /*5*/
+////});
+////
+////type X = { a: { a }, b: { b } }
+////
+////function f4<T extends 'a' | 'b'>(p: { kind: T } & X[T]) { }
+////
+////f4({
+////    kind: "a",
+////    /*6*/
+////})
+
+verify.completions(
+    { marker: "1", exact: [{ name: "world", sortText: completion.SortText.OptionalMember }] },
+    { marker: "2", exact: [{ name: "keyPath", sortText: completion.SortText.OptionalMember }, { name: "autoIncrement", sortText: completion.SortText.OptionalMember }] },
+    { marker: "3", exact: ["r", "g", "b"] },
+    { marker: "4", exact: [{ name: "a", sortText: completion.SortText.OptionalMember }] },
+    { marker: "5", exact: [{ name: "x", sortText: completion.SortText.OptionalMember }] },
+    { marker: "6", exact: ["a"] },
+);
\ No newline at end of file