diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 2f9ad3e33041d..acdb6025c2dfa 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -18176,7 +18176,14 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                     const declarations = concatenate(leftProp.declarations, rightProp.declarations);
                     const flags = SymbolFlags.Property | (leftProp.flags & SymbolFlags.Optional);
                     const result = createSymbol(flags, leftProp.escapedName);
-                    result.links.type = getUnionType([getTypeOfSymbol(leftProp), removeMissingOrUndefinedType(rightType)], UnionReduction.Subtype);
+                    // Optimization: avoid calculating the union type if spreading into the exact same type.
+                    // This is common, e.g. spreading one options bag into another where the bags have the
+                    // same type, or have properties which overlap. If the unions are large, it may turn out
+                    // to be expensive to perform subtype reduction.
+                    const leftType = getTypeOfSymbol(leftProp);
+                    const leftTypeWithoutUndefined = removeMissingOrUndefinedType(leftType);
+                    const rightTypeWithoutUndefined = removeMissingOrUndefinedType(rightType);
+                    result.links.type = leftTypeWithoutUndefined === rightTypeWithoutUndefined ? leftType : getUnionType([leftType, rightTypeWithoutUndefined], UnionReduction.Subtype);
                     result.links.leftSpread = leftProp;
                     result.links.rightSpread = rightProp;
                     result.declarations = declarations;
diff --git a/tests/baselines/reference/spreadObjectPermutations(exactoptionalpropertytypes=false).js b/tests/baselines/reference/spreadObjectPermutations(exactoptionalpropertytypes=false).js
new file mode 100644
index 0000000000000..98964c65cab8b
--- /dev/null
+++ b/tests/baselines/reference/spreadObjectPermutations(exactoptionalpropertytypes=false).js
@@ -0,0 +1,50 @@
+//// [spreadObjectPermutations.ts]
+declare const a: { x: string | number };
+declare const b: { x?: string | number };
+declare const c: { x?: string | number | undefined };
+
+const v_a = { ...a };
+const v_b = { ...b };
+const v_c = { ...c };
+const v_ab = { ...a, ...b };
+const v_ac = { ...a, ...c };
+const v_ba = { ...b, ...a };
+const v_bc = { ...b, ...c };
+const v_ca = { ...c, ...a };
+const v_cb = { ...c, ...b };
+const v_abc = { ...a, ...b, ...c };
+const v_acb = { ...a, ...c, ...b };
+const v_bac = { ...b, ...a, ...c };
+const v_bca = { ...b, ...c, ...a };
+const v_cab = { ...c, ...a, ...b };
+const v_cba = { ...c, ...b, ...a };
+
+
+//// [spreadObjectPermutations.js]
+"use strict";
+var __assign = (this && this.__assign) || function () {
+    __assign = Object.assign || function(t) {
+        for (var s, i = 1, n = arguments.length; i < n; i++) {
+            s = arguments[i];
+            for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
+                t[p] = s[p];
+        }
+        return t;
+    };
+    return __assign.apply(this, arguments);
+};
+var v_a = __assign({}, a);
+var v_b = __assign({}, b);
+var v_c = __assign({}, c);
+var v_ab = __assign(__assign({}, a), b);
+var v_ac = __assign(__assign({}, a), c);
+var v_ba = __assign(__assign({}, b), a);
+var v_bc = __assign(__assign({}, b), c);
+var v_ca = __assign(__assign({}, c), a);
+var v_cb = __assign(__assign({}, c), b);
+var v_abc = __assign(__assign(__assign({}, a), b), c);
+var v_acb = __assign(__assign(__assign({}, a), c), b);
+var v_bac = __assign(__assign(__assign({}, b), a), c);
+var v_bca = __assign(__assign(__assign({}, b), c), a);
+var v_cab = __assign(__assign(__assign({}, c), a), b);
+var v_cba = __assign(__assign(__assign({}, c), b), a);
diff --git a/tests/baselines/reference/spreadObjectPermutations(exactoptionalpropertytypes=false).symbols b/tests/baselines/reference/spreadObjectPermutations(exactoptionalpropertytypes=false).symbols
new file mode 100644
index 0000000000000..cc1b53acb7033
--- /dev/null
+++ b/tests/baselines/reference/spreadObjectPermutations(exactoptionalpropertytypes=false).symbols
@@ -0,0 +1,91 @@
+=== tests/cases/compiler/spreadObjectPermutations.ts ===
+declare const a: { x: string | number };
+>a : Symbol(a, Decl(spreadObjectPermutations.ts, 0, 13))
+>x : Symbol(x, Decl(spreadObjectPermutations.ts, 0, 18))
+
+declare const b: { x?: string | number };
+>b : Symbol(b, Decl(spreadObjectPermutations.ts, 1, 13))
+>x : Symbol(x, Decl(spreadObjectPermutations.ts, 1, 18))
+
+declare const c: { x?: string | number | undefined };
+>c : Symbol(c, Decl(spreadObjectPermutations.ts, 2, 13))
+>x : Symbol(x, Decl(spreadObjectPermutations.ts, 2, 18))
+
+const v_a = { ...a };
+>v_a : Symbol(v_a, Decl(spreadObjectPermutations.ts, 4, 5))
+>a : Symbol(a, Decl(spreadObjectPermutations.ts, 0, 13))
+
+const v_b = { ...b };
+>v_b : Symbol(v_b, Decl(spreadObjectPermutations.ts, 5, 5))
+>b : Symbol(b, Decl(spreadObjectPermutations.ts, 1, 13))
+
+const v_c = { ...c };
+>v_c : Symbol(v_c, Decl(spreadObjectPermutations.ts, 6, 5))
+>c : Symbol(c, Decl(spreadObjectPermutations.ts, 2, 13))
+
+const v_ab = { ...a, ...b };
+>v_ab : Symbol(v_ab, Decl(spreadObjectPermutations.ts, 7, 5))
+>a : Symbol(a, Decl(spreadObjectPermutations.ts, 0, 13))
+>b : Symbol(b, Decl(spreadObjectPermutations.ts, 1, 13))
+
+const v_ac = { ...a, ...c };
+>v_ac : Symbol(v_ac, Decl(spreadObjectPermutations.ts, 8, 5))
+>a : Symbol(a, Decl(spreadObjectPermutations.ts, 0, 13))
+>c : Symbol(c, Decl(spreadObjectPermutations.ts, 2, 13))
+
+const v_ba = { ...b, ...a };
+>v_ba : Symbol(v_ba, Decl(spreadObjectPermutations.ts, 9, 5))
+>b : Symbol(b, Decl(spreadObjectPermutations.ts, 1, 13))
+>a : Symbol(a, Decl(spreadObjectPermutations.ts, 0, 13))
+
+const v_bc = { ...b, ...c };
+>v_bc : Symbol(v_bc, Decl(spreadObjectPermutations.ts, 10, 5))
+>b : Symbol(b, Decl(spreadObjectPermutations.ts, 1, 13))
+>c : Symbol(c, Decl(spreadObjectPermutations.ts, 2, 13))
+
+const v_ca = { ...c, ...a };
+>v_ca : Symbol(v_ca, Decl(spreadObjectPermutations.ts, 11, 5))
+>c : Symbol(c, Decl(spreadObjectPermutations.ts, 2, 13))
+>a : Symbol(a, Decl(spreadObjectPermutations.ts, 0, 13))
+
+const v_cb = { ...c, ...b };
+>v_cb : Symbol(v_cb, Decl(spreadObjectPermutations.ts, 12, 5))
+>c : Symbol(c, Decl(spreadObjectPermutations.ts, 2, 13))
+>b : Symbol(b, Decl(spreadObjectPermutations.ts, 1, 13))
+
+const v_abc = { ...a, ...b, ...c };
+>v_abc : Symbol(v_abc, Decl(spreadObjectPermutations.ts, 13, 5))
+>a : Symbol(a, Decl(spreadObjectPermutations.ts, 0, 13))
+>b : Symbol(b, Decl(spreadObjectPermutations.ts, 1, 13))
+>c : Symbol(c, Decl(spreadObjectPermutations.ts, 2, 13))
+
+const v_acb = { ...a, ...c, ...b };
+>v_acb : Symbol(v_acb, Decl(spreadObjectPermutations.ts, 14, 5))
+>a : Symbol(a, Decl(spreadObjectPermutations.ts, 0, 13))
+>c : Symbol(c, Decl(spreadObjectPermutations.ts, 2, 13))
+>b : Symbol(b, Decl(spreadObjectPermutations.ts, 1, 13))
+
+const v_bac = { ...b, ...a, ...c };
+>v_bac : Symbol(v_bac, Decl(spreadObjectPermutations.ts, 15, 5))
+>b : Symbol(b, Decl(spreadObjectPermutations.ts, 1, 13))
+>a : Symbol(a, Decl(spreadObjectPermutations.ts, 0, 13))
+>c : Symbol(c, Decl(spreadObjectPermutations.ts, 2, 13))
+
+const v_bca = { ...b, ...c, ...a };
+>v_bca : Symbol(v_bca, Decl(spreadObjectPermutations.ts, 16, 5))
+>b : Symbol(b, Decl(spreadObjectPermutations.ts, 1, 13))
+>c : Symbol(c, Decl(spreadObjectPermutations.ts, 2, 13))
+>a : Symbol(a, Decl(spreadObjectPermutations.ts, 0, 13))
+
+const v_cab = { ...c, ...a, ...b };
+>v_cab : Symbol(v_cab, Decl(spreadObjectPermutations.ts, 17, 5))
+>c : Symbol(c, Decl(spreadObjectPermutations.ts, 2, 13))
+>a : Symbol(a, Decl(spreadObjectPermutations.ts, 0, 13))
+>b : Symbol(b, Decl(spreadObjectPermutations.ts, 1, 13))
+
+const v_cba = { ...c, ...b, ...a };
+>v_cba : Symbol(v_cba, Decl(spreadObjectPermutations.ts, 18, 5))
+>c : Symbol(c, Decl(spreadObjectPermutations.ts, 2, 13))
+>b : Symbol(b, Decl(spreadObjectPermutations.ts, 1, 13))
+>a : Symbol(a, Decl(spreadObjectPermutations.ts, 0, 13))
+
diff --git a/tests/baselines/reference/spreadObjectPermutations(exactoptionalpropertytypes=false).types b/tests/baselines/reference/spreadObjectPermutations(exactoptionalpropertytypes=false).types
new file mode 100644
index 0000000000000..cd47d89594167
--- /dev/null
+++ b/tests/baselines/reference/spreadObjectPermutations(exactoptionalpropertytypes=false).types
@@ -0,0 +1,106 @@
+=== tests/cases/compiler/spreadObjectPermutations.ts ===
+declare const a: { x: string | number };
+>a : { x: string | number; }
+>x : string | number
+
+declare const b: { x?: string | number };
+>b : { x?: string | number | undefined; }
+>x : string | number | undefined
+
+declare const c: { x?: string | number | undefined };
+>c : { x?: string | number | undefined; }
+>x : string | number | undefined
+
+const v_a = { ...a };
+>v_a : { x: string | number; }
+>{ ...a } : { x: string | number; }
+>a : { x: string | number; }
+
+const v_b = { ...b };
+>v_b : { x?: string | number | undefined; }
+>{ ...b } : { x?: string | number | undefined; }
+>b : { x?: string | number | undefined; }
+
+const v_c = { ...c };
+>v_c : { x?: string | number | undefined; }
+>{ ...c } : { x?: string | number | undefined; }
+>c : { x?: string | number | undefined; }
+
+const v_ab = { ...a, ...b };
+>v_ab : { x: string | number; }
+>{ ...a, ...b } : { x: string | number; }
+>a : { x: string | number; }
+>b : { x?: string | number | undefined; }
+
+const v_ac = { ...a, ...c };
+>v_ac : { x: string | number; }
+>{ ...a, ...c } : { x: string | number; }
+>a : { x: string | number; }
+>c : { x?: string | number | undefined; }
+
+const v_ba = { ...b, ...a };
+>v_ba : { x: string | number; }
+>{ ...b, ...a } : { x: string | number; }
+>b : { x?: string | number | undefined; }
+>a : { x: string | number; }
+
+const v_bc = { ...b, ...c };
+>v_bc : { x?: string | number | undefined; }
+>{ ...b, ...c } : { x?: string | number | undefined; }
+>b : { x?: string | number | undefined; }
+>c : { x?: string | number | undefined; }
+
+const v_ca = { ...c, ...a };
+>v_ca : { x: string | number; }
+>{ ...c, ...a } : { x: string | number; }
+>c : { x?: string | number | undefined; }
+>a : { x: string | number; }
+
+const v_cb = { ...c, ...b };
+>v_cb : { x?: string | number | undefined; }
+>{ ...c, ...b } : { x?: string | number | undefined; }
+>c : { x?: string | number | undefined; }
+>b : { x?: string | number | undefined; }
+
+const v_abc = { ...a, ...b, ...c };
+>v_abc : { x: string | number; }
+>{ ...a, ...b, ...c } : { x: string | number; }
+>a : { x: string | number; }
+>b : { x?: string | number | undefined; }
+>c : { x?: string | number | undefined; }
+
+const v_acb = { ...a, ...c, ...b };
+>v_acb : { x: string | number; }
+>{ ...a, ...c, ...b } : { x: string | number; }
+>a : { x: string | number; }
+>c : { x?: string | number | undefined; }
+>b : { x?: string | number | undefined; }
+
+const v_bac = { ...b, ...a, ...c };
+>v_bac : { x: string | number; }
+>{ ...b, ...a, ...c } : { x: string | number; }
+>b : { x?: string | number | undefined; }
+>a : { x: string | number; }
+>c : { x?: string | number | undefined; }
+
+const v_bca = { ...b, ...c, ...a };
+>v_bca : { x: string | number; }
+>{ ...b, ...c, ...a } : { x: string | number; }
+>b : { x?: string | number | undefined; }
+>c : { x?: string | number | undefined; }
+>a : { x: string | number; }
+
+const v_cab = { ...c, ...a, ...b };
+>v_cab : { x: string | number; }
+>{ ...c, ...a, ...b } : { x: string | number; }
+>c : { x?: string | number | undefined; }
+>a : { x: string | number; }
+>b : { x?: string | number | undefined; }
+
+const v_cba = { ...c, ...b, ...a };
+>v_cba : { x: string | number; }
+>{ ...c, ...b, ...a } : { x: string | number; }
+>c : { x?: string | number | undefined; }
+>b : { x?: string | number | undefined; }
+>a : { x: string | number; }
+
diff --git a/tests/baselines/reference/spreadObjectPermutations(exactoptionalpropertytypes=true).js b/tests/baselines/reference/spreadObjectPermutations(exactoptionalpropertytypes=true).js
new file mode 100644
index 0000000000000..98964c65cab8b
--- /dev/null
+++ b/tests/baselines/reference/spreadObjectPermutations(exactoptionalpropertytypes=true).js
@@ -0,0 +1,50 @@
+//// [spreadObjectPermutations.ts]
+declare const a: { x: string | number };
+declare const b: { x?: string | number };
+declare const c: { x?: string | number | undefined };
+
+const v_a = { ...a };
+const v_b = { ...b };
+const v_c = { ...c };
+const v_ab = { ...a, ...b };
+const v_ac = { ...a, ...c };
+const v_ba = { ...b, ...a };
+const v_bc = { ...b, ...c };
+const v_ca = { ...c, ...a };
+const v_cb = { ...c, ...b };
+const v_abc = { ...a, ...b, ...c };
+const v_acb = { ...a, ...c, ...b };
+const v_bac = { ...b, ...a, ...c };
+const v_bca = { ...b, ...c, ...a };
+const v_cab = { ...c, ...a, ...b };
+const v_cba = { ...c, ...b, ...a };
+
+
+//// [spreadObjectPermutations.js]
+"use strict";
+var __assign = (this && this.__assign) || function () {
+    __assign = Object.assign || function(t) {
+        for (var s, i = 1, n = arguments.length; i < n; i++) {
+            s = arguments[i];
+            for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
+                t[p] = s[p];
+        }
+        return t;
+    };
+    return __assign.apply(this, arguments);
+};
+var v_a = __assign({}, a);
+var v_b = __assign({}, b);
+var v_c = __assign({}, c);
+var v_ab = __assign(__assign({}, a), b);
+var v_ac = __assign(__assign({}, a), c);
+var v_ba = __assign(__assign({}, b), a);
+var v_bc = __assign(__assign({}, b), c);
+var v_ca = __assign(__assign({}, c), a);
+var v_cb = __assign(__assign({}, c), b);
+var v_abc = __assign(__assign(__assign({}, a), b), c);
+var v_acb = __assign(__assign(__assign({}, a), c), b);
+var v_bac = __assign(__assign(__assign({}, b), a), c);
+var v_bca = __assign(__assign(__assign({}, b), c), a);
+var v_cab = __assign(__assign(__assign({}, c), a), b);
+var v_cba = __assign(__assign(__assign({}, c), b), a);
diff --git a/tests/baselines/reference/spreadObjectPermutations(exactoptionalpropertytypes=true).symbols b/tests/baselines/reference/spreadObjectPermutations(exactoptionalpropertytypes=true).symbols
new file mode 100644
index 0000000000000..cc1b53acb7033
--- /dev/null
+++ b/tests/baselines/reference/spreadObjectPermutations(exactoptionalpropertytypes=true).symbols
@@ -0,0 +1,91 @@
+=== tests/cases/compiler/spreadObjectPermutations.ts ===
+declare const a: { x: string | number };
+>a : Symbol(a, Decl(spreadObjectPermutations.ts, 0, 13))
+>x : Symbol(x, Decl(spreadObjectPermutations.ts, 0, 18))
+
+declare const b: { x?: string | number };
+>b : Symbol(b, Decl(spreadObjectPermutations.ts, 1, 13))
+>x : Symbol(x, Decl(spreadObjectPermutations.ts, 1, 18))
+
+declare const c: { x?: string | number | undefined };
+>c : Symbol(c, Decl(spreadObjectPermutations.ts, 2, 13))
+>x : Symbol(x, Decl(spreadObjectPermutations.ts, 2, 18))
+
+const v_a = { ...a };
+>v_a : Symbol(v_a, Decl(spreadObjectPermutations.ts, 4, 5))
+>a : Symbol(a, Decl(spreadObjectPermutations.ts, 0, 13))
+
+const v_b = { ...b };
+>v_b : Symbol(v_b, Decl(spreadObjectPermutations.ts, 5, 5))
+>b : Symbol(b, Decl(spreadObjectPermutations.ts, 1, 13))
+
+const v_c = { ...c };
+>v_c : Symbol(v_c, Decl(spreadObjectPermutations.ts, 6, 5))
+>c : Symbol(c, Decl(spreadObjectPermutations.ts, 2, 13))
+
+const v_ab = { ...a, ...b };
+>v_ab : Symbol(v_ab, Decl(spreadObjectPermutations.ts, 7, 5))
+>a : Symbol(a, Decl(spreadObjectPermutations.ts, 0, 13))
+>b : Symbol(b, Decl(spreadObjectPermutations.ts, 1, 13))
+
+const v_ac = { ...a, ...c };
+>v_ac : Symbol(v_ac, Decl(spreadObjectPermutations.ts, 8, 5))
+>a : Symbol(a, Decl(spreadObjectPermutations.ts, 0, 13))
+>c : Symbol(c, Decl(spreadObjectPermutations.ts, 2, 13))
+
+const v_ba = { ...b, ...a };
+>v_ba : Symbol(v_ba, Decl(spreadObjectPermutations.ts, 9, 5))
+>b : Symbol(b, Decl(spreadObjectPermutations.ts, 1, 13))
+>a : Symbol(a, Decl(spreadObjectPermutations.ts, 0, 13))
+
+const v_bc = { ...b, ...c };
+>v_bc : Symbol(v_bc, Decl(spreadObjectPermutations.ts, 10, 5))
+>b : Symbol(b, Decl(spreadObjectPermutations.ts, 1, 13))
+>c : Symbol(c, Decl(spreadObjectPermutations.ts, 2, 13))
+
+const v_ca = { ...c, ...a };
+>v_ca : Symbol(v_ca, Decl(spreadObjectPermutations.ts, 11, 5))
+>c : Symbol(c, Decl(spreadObjectPermutations.ts, 2, 13))
+>a : Symbol(a, Decl(spreadObjectPermutations.ts, 0, 13))
+
+const v_cb = { ...c, ...b };
+>v_cb : Symbol(v_cb, Decl(spreadObjectPermutations.ts, 12, 5))
+>c : Symbol(c, Decl(spreadObjectPermutations.ts, 2, 13))
+>b : Symbol(b, Decl(spreadObjectPermutations.ts, 1, 13))
+
+const v_abc = { ...a, ...b, ...c };
+>v_abc : Symbol(v_abc, Decl(spreadObjectPermutations.ts, 13, 5))
+>a : Symbol(a, Decl(spreadObjectPermutations.ts, 0, 13))
+>b : Symbol(b, Decl(spreadObjectPermutations.ts, 1, 13))
+>c : Symbol(c, Decl(spreadObjectPermutations.ts, 2, 13))
+
+const v_acb = { ...a, ...c, ...b };
+>v_acb : Symbol(v_acb, Decl(spreadObjectPermutations.ts, 14, 5))
+>a : Symbol(a, Decl(spreadObjectPermutations.ts, 0, 13))
+>c : Symbol(c, Decl(spreadObjectPermutations.ts, 2, 13))
+>b : Symbol(b, Decl(spreadObjectPermutations.ts, 1, 13))
+
+const v_bac = { ...b, ...a, ...c };
+>v_bac : Symbol(v_bac, Decl(spreadObjectPermutations.ts, 15, 5))
+>b : Symbol(b, Decl(spreadObjectPermutations.ts, 1, 13))
+>a : Symbol(a, Decl(spreadObjectPermutations.ts, 0, 13))
+>c : Symbol(c, Decl(spreadObjectPermutations.ts, 2, 13))
+
+const v_bca = { ...b, ...c, ...a };
+>v_bca : Symbol(v_bca, Decl(spreadObjectPermutations.ts, 16, 5))
+>b : Symbol(b, Decl(spreadObjectPermutations.ts, 1, 13))
+>c : Symbol(c, Decl(spreadObjectPermutations.ts, 2, 13))
+>a : Symbol(a, Decl(spreadObjectPermutations.ts, 0, 13))
+
+const v_cab = { ...c, ...a, ...b };
+>v_cab : Symbol(v_cab, Decl(spreadObjectPermutations.ts, 17, 5))
+>c : Symbol(c, Decl(spreadObjectPermutations.ts, 2, 13))
+>a : Symbol(a, Decl(spreadObjectPermutations.ts, 0, 13))
+>b : Symbol(b, Decl(spreadObjectPermutations.ts, 1, 13))
+
+const v_cba = { ...c, ...b, ...a };
+>v_cba : Symbol(v_cba, Decl(spreadObjectPermutations.ts, 18, 5))
+>c : Symbol(c, Decl(spreadObjectPermutations.ts, 2, 13))
+>b : Symbol(b, Decl(spreadObjectPermutations.ts, 1, 13))
+>a : Symbol(a, Decl(spreadObjectPermutations.ts, 0, 13))
+
diff --git a/tests/baselines/reference/spreadObjectPermutations(exactoptionalpropertytypes=true).types b/tests/baselines/reference/spreadObjectPermutations(exactoptionalpropertytypes=true).types
new file mode 100644
index 0000000000000..58332782b0335
--- /dev/null
+++ b/tests/baselines/reference/spreadObjectPermutations(exactoptionalpropertytypes=true).types
@@ -0,0 +1,106 @@
+=== tests/cases/compiler/spreadObjectPermutations.ts ===
+declare const a: { x: string | number };
+>a : { x: string | number; }
+>x : string | number
+
+declare const b: { x?: string | number };
+>b : { x?: string | number; }
+>x : string | number | undefined
+
+declare const c: { x?: string | number | undefined };
+>c : { x?: string | number | undefined; }
+>x : string | number | undefined
+
+const v_a = { ...a };
+>v_a : { x: string | number; }
+>{ ...a } : { x: string | number; }
+>a : { x: string | number; }
+
+const v_b = { ...b };
+>v_b : { x?: string | number; }
+>{ ...b } : { x?: string | number; }
+>b : { x?: string | number; }
+
+const v_c = { ...c };
+>v_c : { x?: string | number | undefined; }
+>{ ...c } : { x?: string | number | undefined; }
+>c : { x?: string | number | undefined; }
+
+const v_ab = { ...a, ...b };
+>v_ab : { x: string | number; }
+>{ ...a, ...b } : { x: string | number; }
+>a : { x: string | number; }
+>b : { x?: string | number; }
+
+const v_ac = { ...a, ...c };
+>v_ac : { x: string | number | undefined; }
+>{ ...a, ...c } : { x: string | number | undefined; }
+>a : { x: string | number; }
+>c : { x?: string | number | undefined; }
+
+const v_ba = { ...b, ...a };
+>v_ba : { x: string | number; }
+>{ ...b, ...a } : { x: string | number; }
+>b : { x?: string | number; }
+>a : { x: string | number; }
+
+const v_bc = { ...b, ...c };
+>v_bc : { x?: string | number | undefined; }
+>{ ...b, ...c } : { x?: string | number | undefined; }
+>b : { x?: string | number; }
+>c : { x?: string | number | undefined; }
+
+const v_ca = { ...c, ...a };
+>v_ca : { x: string | number; }
+>{ ...c, ...a } : { x: string | number; }
+>c : { x?: string | number | undefined; }
+>a : { x: string | number; }
+
+const v_cb = { ...c, ...b };
+>v_cb : { x?: string | number | undefined; }
+>{ ...c, ...b } : { x?: string | number | undefined; }
+>c : { x?: string | number | undefined; }
+>b : { x?: string | number; }
+
+const v_abc = { ...a, ...b, ...c };
+>v_abc : { x: string | number | undefined; }
+>{ ...a, ...b, ...c } : { x: string | number | undefined; }
+>a : { x: string | number; }
+>b : { x?: string | number; }
+>c : { x?: string | number | undefined; }
+
+const v_acb = { ...a, ...c, ...b };
+>v_acb : { x: string | number | undefined; }
+>{ ...a, ...c, ...b } : { x: string | number | undefined; }
+>a : { x: string | number; }
+>c : { x?: string | number | undefined; }
+>b : { x?: string | number; }
+
+const v_bac = { ...b, ...a, ...c };
+>v_bac : { x: string | number | undefined; }
+>{ ...b, ...a, ...c } : { x: string | number | undefined; }
+>b : { x?: string | number; }
+>a : { x: string | number; }
+>c : { x?: string | number | undefined; }
+
+const v_bca = { ...b, ...c, ...a };
+>v_bca : { x: string | number; }
+>{ ...b, ...c, ...a } : { x: string | number; }
+>b : { x?: string | number; }
+>c : { x?: string | number | undefined; }
+>a : { x: string | number; }
+
+const v_cab = { ...c, ...a, ...b };
+>v_cab : { x: string | number; }
+>{ ...c, ...a, ...b } : { x: string | number; }
+>c : { x?: string | number | undefined; }
+>a : { x: string | number; }
+>b : { x?: string | number; }
+
+const v_cba = { ...c, ...b, ...a };
+>v_cba : { x: string | number; }
+>{ ...c, ...b, ...a } : { x: string | number; }
+>c : { x?: string | number | undefined; }
+>b : { x?: string | number; }
+>a : { x: string | number; }
+
diff --git a/tests/cases/compiler/spreadObjectPermutations.ts b/tests/cases/compiler/spreadObjectPermutations.ts
new file mode 100644
index 0000000000000..c047601c31d1b
--- /dev/null
+++ b/tests/cases/compiler/spreadObjectPermutations.ts
@@ -0,0 +1,23 @@
+// @strict: true
+// @exactOptionalPropertyTypes: false, true
+
+
+declare const a: { x: string | number };
+declare const b: { x?: string | number };
+declare const c: { x?: string | number | undefined };
+
+const v_a = { ...a };
+const v_b = { ...b };
+const v_c = { ...c };
+const v_ab = { ...a, ...b };
+const v_ac = { ...a, ...c };
+const v_ba = { ...b, ...a };
+const v_bc = { ...b, ...c };
+const v_ca = { ...c, ...a };
+const v_cb = { ...c, ...b };
+const v_abc = { ...a, ...b, ...c };
+const v_acb = { ...a, ...c, ...b };
+const v_bac = { ...b, ...a, ...c };
+const v_bca = { ...b, ...c, ...a };
+const v_cab = { ...c, ...a, ...b };
+const v_cba = { ...c, ...b, ...a };