diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 48bc0da113816..b8f7251bb067b 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -27316,12 +27316,17 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                             if (middleLength === 2) {
                                 if (elementFlags[startLength] & elementFlags[startLength + 1] & ElementFlags.Variadic) {
                                     // Middle of target is [...T, ...U] and source is tuple type
-                                    const targetInfo = getInferenceInfoForType(elementTypes[startLength]);
+                                    let targetInfo = getInferenceInfoForType(elementTypes[startLength]);
                                     if (targetInfo && targetInfo.impliedArity !== undefined) {
                                         // Infer slices from source based on implied arity of T.
                                         inferFromTypes(sliceTupleType(source, startLength, endLength + sourceArity - targetInfo.impliedArity), elementTypes[startLength]);
                                         inferFromTypes(sliceTupleType(source, startLength + targetInfo.impliedArity, endLength), elementTypes[startLength + 1]);
                                     }
+                                    else if ((targetInfo = getInferenceInfoForType(elementTypes[startLength + 1]))?.impliedArity !== undefined) {
+                                        // Infer slices from source based on implied arity of U.
+                                        inferFromTypes(sliceTupleType(source, startLength, endLength + targetInfo!.impliedArity), elementTypes[startLength]);
+                                        inferFromTypes(sliceTupleType(source, startLength + sourceArity - endLength - targetInfo!.impliedArity, endLength), elementTypes[startLength + 1]);
+                                    }
                                 }
                                 else if (elementFlags[startLength] & ElementFlags.Variadic && elementFlags[startLength + 1] & ElementFlags.Rest) {
                                     // Middle of target is [...T, ...rest] and source is tuple type
diff --git a/tests/baselines/reference/variadicTuples4.symbols b/tests/baselines/reference/variadicTuples4.symbols
new file mode 100644
index 0000000000000..1f4cbd8ff833f
--- /dev/null
+++ b/tests/baselines/reference/variadicTuples4.symbols
@@ -0,0 +1,140 @@
+//// [tests/cases/conformance/types/tuple/variadicTuples4.ts] ////
+
+=== variadicTuples4.ts ===
+// https://github.com/microsoft/TypeScript/issues/56970
+
+function partialCall1<T extends readonly any[], U extends readonly any[], R>(
+>partialCall1 : Symbol(partialCall1, Decl(variadicTuples4.ts, 0, 0))
+>T : Symbol(T, Decl(variadicTuples4.ts, 2, 22))
+>U : Symbol(U, Decl(variadicTuples4.ts, 2, 47))
+>R : Symbol(R, Decl(variadicTuples4.ts, 2, 73))
+
+  f: (...args: [...U, ...T]) => R,
+>f : Symbol(f, Decl(variadicTuples4.ts, 2, 77))
+>args : Symbol(args, Decl(variadicTuples4.ts, 3, 6))
+>U : Symbol(U, Decl(variadicTuples4.ts, 2, 47))
+>T : Symbol(T, Decl(variadicTuples4.ts, 2, 22))
+>R : Symbol(R, Decl(variadicTuples4.ts, 2, 73))
+
+  ...tailArgs: T
+>tailArgs : Symbol(tailArgs, Decl(variadicTuples4.ts, 3, 34))
+>T : Symbol(T, Decl(variadicTuples4.ts, 2, 22))
+
+) {
+  return (...headArgs: U) => f(...headArgs, ...tailArgs);
+>headArgs : Symbol(headArgs, Decl(variadicTuples4.ts, 6, 10))
+>U : Symbol(U, Decl(variadicTuples4.ts, 2, 47))
+>f : Symbol(f, Decl(variadicTuples4.ts, 2, 77))
+>headArgs : Symbol(headArgs, Decl(variadicTuples4.ts, 6, 10))
+>tailArgs : Symbol(tailArgs, Decl(variadicTuples4.ts, 3, 34))
+}
+
+function source1(a: number, b: number, c: number): number {
+>source1 : Symbol(source1, Decl(variadicTuples4.ts, 7, 1))
+>a : Symbol(a, Decl(variadicTuples4.ts, 9, 17))
+>b : Symbol(b, Decl(variadicTuples4.ts, 9, 27))
+>c : Symbol(c, Decl(variadicTuples4.ts, 9, 38))
+
+  return a + b + c;
+>a : Symbol(a, Decl(variadicTuples4.ts, 9, 17))
+>b : Symbol(b, Decl(variadicTuples4.ts, 9, 27))
+>c : Symbol(c, Decl(variadicTuples4.ts, 9, 38))
+}
+
+const result1 = partialCall1(source1, 1);
+>result1 : Symbol(result1, Decl(variadicTuples4.ts, 13, 5))
+>partialCall1 : Symbol(partialCall1, Decl(variadicTuples4.ts, 0, 0))
+>source1 : Symbol(source1, Decl(variadicTuples4.ts, 7, 1))
+
+function partialCall2<T extends readonly any[], U extends readonly any[], R>(
+>partialCall2 : Symbol(partialCall2, Decl(variadicTuples4.ts, 13, 41))
+>T : Symbol(T, Decl(variadicTuples4.ts, 15, 22))
+>U : Symbol(U, Decl(variadicTuples4.ts, 15, 47))
+>R : Symbol(R, Decl(variadicTuples4.ts, 15, 73))
+
+  f: (...args: [number, ...U, ...T]) => R,
+>f : Symbol(f, Decl(variadicTuples4.ts, 15, 77))
+>args : Symbol(args, Decl(variadicTuples4.ts, 16, 6))
+>U : Symbol(U, Decl(variadicTuples4.ts, 15, 47))
+>T : Symbol(T, Decl(variadicTuples4.ts, 15, 22))
+>R : Symbol(R, Decl(variadicTuples4.ts, 15, 73))
+
+  ...tailArgs: T
+>tailArgs : Symbol(tailArgs, Decl(variadicTuples4.ts, 16, 42))
+>T : Symbol(T, Decl(variadicTuples4.ts, 15, 22))
+
+) {
+  return (...headArgs: U) => f(0, ...headArgs, ...tailArgs);
+>headArgs : Symbol(headArgs, Decl(variadicTuples4.ts, 19, 10))
+>U : Symbol(U, Decl(variadicTuples4.ts, 15, 47))
+>f : Symbol(f, Decl(variadicTuples4.ts, 15, 77))
+>headArgs : Symbol(headArgs, Decl(variadicTuples4.ts, 19, 10))
+>tailArgs : Symbol(tailArgs, Decl(variadicTuples4.ts, 16, 42))
+}
+
+function source2(a: number, b: number, c: number, d: number): number {
+>source2 : Symbol(source2, Decl(variadicTuples4.ts, 20, 1))
+>a : Symbol(a, Decl(variadicTuples4.ts, 22, 17))
+>b : Symbol(b, Decl(variadicTuples4.ts, 22, 27))
+>c : Symbol(c, Decl(variadicTuples4.ts, 22, 38))
+>d : Symbol(d, Decl(variadicTuples4.ts, 22, 49))
+
+  return a + b + c + d;
+>a : Symbol(a, Decl(variadicTuples4.ts, 22, 17))
+>b : Symbol(b, Decl(variadicTuples4.ts, 22, 27))
+>c : Symbol(c, Decl(variadicTuples4.ts, 22, 38))
+>d : Symbol(d, Decl(variadicTuples4.ts, 22, 49))
+}
+
+const result2 = partialCall2(source2, 1);
+>result2 : Symbol(result2, Decl(variadicTuples4.ts, 26, 5))
+>partialCall2 : Symbol(partialCall2, Decl(variadicTuples4.ts, 13, 41))
+>source2 : Symbol(source2, Decl(variadicTuples4.ts, 20, 1))
+
+function partialCall3<T extends readonly any[], U extends readonly any[], R>(
+>partialCall3 : Symbol(partialCall3, Decl(variadicTuples4.ts, 26, 41))
+>T : Symbol(T, Decl(variadicTuples4.ts, 28, 22))
+>U : Symbol(U, Decl(variadicTuples4.ts, 28, 47))
+>R : Symbol(R, Decl(variadicTuples4.ts, 28, 73))
+
+  f: (...args: [...U, ...T, number]) => R,
+>f : Symbol(f, Decl(variadicTuples4.ts, 28, 77))
+>args : Symbol(args, Decl(variadicTuples4.ts, 29, 6))
+>U : Symbol(U, Decl(variadicTuples4.ts, 28, 47))
+>T : Symbol(T, Decl(variadicTuples4.ts, 28, 22))
+>R : Symbol(R, Decl(variadicTuples4.ts, 28, 73))
+
+  ...tailArgs: T
+>tailArgs : Symbol(tailArgs, Decl(variadicTuples4.ts, 29, 42))
+>T : Symbol(T, Decl(variadicTuples4.ts, 28, 22))
+
+) {
+  return (...headArgs: U) => f(...headArgs, ...tailArgs, 100);
+>headArgs : Symbol(headArgs, Decl(variadicTuples4.ts, 32, 10))
+>U : Symbol(U, Decl(variadicTuples4.ts, 28, 47))
+>f : Symbol(f, Decl(variadicTuples4.ts, 28, 77))
+>headArgs : Symbol(headArgs, Decl(variadicTuples4.ts, 32, 10))
+>tailArgs : Symbol(tailArgs, Decl(variadicTuples4.ts, 29, 42))
+}
+
+function source3(a: number, b: number, c: number, d: number): number {
+>source3 : Symbol(source3, Decl(variadicTuples4.ts, 33, 1))
+>a : Symbol(a, Decl(variadicTuples4.ts, 35, 17))
+>b : Symbol(b, Decl(variadicTuples4.ts, 35, 27))
+>c : Symbol(c, Decl(variadicTuples4.ts, 35, 38))
+>d : Symbol(d, Decl(variadicTuples4.ts, 35, 49))
+
+  return a + b + c + d;
+>a : Symbol(a, Decl(variadicTuples4.ts, 35, 17))
+>b : Symbol(b, Decl(variadicTuples4.ts, 35, 27))
+>c : Symbol(c, Decl(variadicTuples4.ts, 35, 38))
+>d : Symbol(d, Decl(variadicTuples4.ts, 35, 49))
+}
+
+const result3 = partialCall3(source3, 1);
+>result3 : Symbol(result3, Decl(variadicTuples4.ts, 39, 5))
+>partialCall3 : Symbol(partialCall3, Decl(variadicTuples4.ts, 26, 41))
+>source3 : Symbol(source3, Decl(variadicTuples4.ts, 33, 1))
+
+export {}
+
diff --git a/tests/baselines/reference/variadicTuples4.types b/tests/baselines/reference/variadicTuples4.types
new file mode 100644
index 0000000000000..181f1d90f82af
--- /dev/null
+++ b/tests/baselines/reference/variadicTuples4.types
@@ -0,0 +1,224 @@
+//// [tests/cases/conformance/types/tuple/variadicTuples4.ts] ////
+
+=== variadicTuples4.ts ===
+// https://github.com/microsoft/TypeScript/issues/56970
+
+function partialCall1<T extends readonly any[], U extends readonly any[], R>(
+>partialCall1 : <T extends readonly any[], U extends readonly any[], R>(f: (...args: [...U, ...T]) => R, ...tailArgs: T) => (...headArgs: U) => R
+>             : ^ ^^^^^^^^^              ^^ ^^^^^^^^^              ^^ ^^ ^^                            ^^^^^        ^^ ^^^^^^              ^^^^^^
+
+  f: (...args: [...U, ...T]) => R,
+>f : (...args: [...U, ...T]) => R
+>  : ^^^^    ^^            ^^^^^ 
+>args : [...U, ...T]
+>     : ^^^^^^^^^^^^
+
+  ...tailArgs: T
+>tailArgs : T
+>         : ^
+
+) {
+  return (...headArgs: U) => f(...headArgs, ...tailArgs);
+>(...headArgs: U) => f(...headArgs, ...tailArgs) : (...headArgs: U) => R
+>                                                : ^^^^        ^^ ^^^^^^
+>headArgs : U
+>         : ^
+>f(...headArgs, ...tailArgs) : R
+>                            : ^
+>f : (...args: [...U, ...T]) => R
+>  : ^^^^    ^^            ^^^^^ 
+>...headArgs : any
+>headArgs : U
+>         : ^
+>...tailArgs : any
+>tailArgs : T
+>         : ^
+}
+
+function source1(a: number, b: number, c: number): number {
+>source1 : (a: number, b: number, c: number) => number
+>        : ^ ^^      ^^ ^^      ^^ ^^      ^^^^^      
+>a : number
+>  : ^^^^^^
+>b : number
+>  : ^^^^^^
+>c : number
+>  : ^^^^^^
+
+  return a + b + c;
+>a + b + c : number
+>          : ^^^^^^
+>a + b : number
+>      : ^^^^^^
+>a : number
+>  : ^^^^^^
+>b : number
+>  : ^^^^^^
+>c : number
+>  : ^^^^^^
+}
+
+const result1 = partialCall1(source1, 1);
+>result1 : (a: number, b: number) => number
+>        : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+>partialCall1(source1, 1) : (a: number, b: number) => number
+>                         : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+>partialCall1 : <T extends readonly any[], U extends readonly any[], R>(f: (...args: [...U, ...T]) => R, ...tailArgs: T) => (...headArgs: U) => R
+>             : ^ ^^^^^^^^^              ^^ ^^^^^^^^^              ^^ ^^ ^^                            ^^^^^        ^^ ^^^^^^              ^^^^^^
+>source1 : (a: number, b: number, c: number) => number
+>        : ^ ^^      ^^ ^^      ^^ ^^      ^^^^^      
+>1 : 1
+>  : ^
+
+function partialCall2<T extends readonly any[], U extends readonly any[], R>(
+>partialCall2 : <T extends readonly any[], U extends readonly any[], R>(f: (...args: [number, ...U, ...T]) => R, ...tailArgs: T) => (...headArgs: U) => R
+>             : ^ ^^^^^^^^^              ^^ ^^^^^^^^^              ^^ ^^ ^^                                    ^^^^^        ^^ ^^^^^^              ^^^^^^
+
+  f: (...args: [number, ...U, ...T]) => R,
+>f : (...args: [number, ...U, ...T]) => R
+>  : ^^^^    ^^                    ^^^^^ 
+>args : [number, ...U, ...T]
+>     : ^^^^^^^^^^^^^^^^^^^^
+
+  ...tailArgs: T
+>tailArgs : T
+>         : ^
+
+) {
+  return (...headArgs: U) => f(0, ...headArgs, ...tailArgs);
+>(...headArgs: U) => f(0, ...headArgs, ...tailArgs) : (...headArgs: U) => R
+>                                                   : ^^^^        ^^ ^^^^^^
+>headArgs : U
+>         : ^
+>f(0, ...headArgs, ...tailArgs) : R
+>                               : ^
+>f : (...args: [number, ...U, ...T]) => R
+>  : ^^^^    ^^                    ^^^^^ 
+>0 : 0
+>  : ^
+>...headArgs : any
+>headArgs : U
+>         : ^
+>...tailArgs : any
+>tailArgs : T
+>         : ^
+}
+
+function source2(a: number, b: number, c: number, d: number): number {
+>source2 : (a: number, b: number, c: number, d: number) => number
+>        : ^ ^^      ^^ ^^      ^^ ^^      ^^ ^^      ^^^^^      
+>a : number
+>  : ^^^^^^
+>b : number
+>  : ^^^^^^
+>c : number
+>  : ^^^^^^
+>d : number
+>  : ^^^^^^
+
+  return a + b + c + d;
+>a + b + c + d : number
+>              : ^^^^^^
+>a + b + c : number
+>          : ^^^^^^
+>a + b : number
+>      : ^^^^^^
+>a : number
+>  : ^^^^^^
+>b : number
+>  : ^^^^^^
+>c : number
+>  : ^^^^^^
+>d : number
+>  : ^^^^^^
+}
+
+const result2 = partialCall2(source2, 1);
+>result2 : (b: number, c: number) => number
+>        : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+>partialCall2(source2, 1) : (b: number, c: number) => number
+>                         : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+>partialCall2 : <T extends readonly any[], U extends readonly any[], R>(f: (...args: [number, ...U, ...T]) => R, ...tailArgs: T) => (...headArgs: U) => R
+>             : ^ ^^^^^^^^^              ^^ ^^^^^^^^^              ^^ ^^ ^^                                    ^^^^^        ^^ ^^^^^^              ^^^^^^
+>source2 : (a: number, b: number, c: number, d: number) => number
+>        : ^ ^^      ^^ ^^      ^^ ^^      ^^ ^^      ^^^^^      
+>1 : 1
+>  : ^
+
+function partialCall3<T extends readonly any[], U extends readonly any[], R>(
+>partialCall3 : <T extends readonly any[], U extends readonly any[], R>(f: (...args: [...U, ...T, number]) => R, ...tailArgs: T) => (...headArgs: U) => R
+>             : ^ ^^^^^^^^^              ^^ ^^^^^^^^^              ^^ ^^ ^^                                    ^^^^^        ^^ ^^^^^^              ^^^^^^
+
+  f: (...args: [...U, ...T, number]) => R,
+>f : (...args: [...U, ...T, number]) => R
+>  : ^^^^    ^^                    ^^^^^ 
+>args : [...U, ...T, number]
+>     : ^^^^^^^^^^^^^^^^^^^^
+
+  ...tailArgs: T
+>tailArgs : T
+>         : ^
+
+) {
+  return (...headArgs: U) => f(...headArgs, ...tailArgs, 100);
+>(...headArgs: U) => f(...headArgs, ...tailArgs, 100) : (...headArgs: U) => R
+>                                                     : ^^^^        ^^ ^^^^^^
+>headArgs : U
+>         : ^
+>f(...headArgs, ...tailArgs, 100) : R
+>                                 : ^
+>f : (...args: [...U, ...T, number]) => R
+>  : ^^^^    ^^                    ^^^^^ 
+>...headArgs : any
+>headArgs : U
+>         : ^
+>...tailArgs : any
+>tailArgs : T
+>         : ^
+>100 : 100
+>    : ^^^
+}
+
+function source3(a: number, b: number, c: number, d: number): number {
+>source3 : (a: number, b: number, c: number, d: number) => number
+>        : ^ ^^      ^^ ^^      ^^ ^^      ^^ ^^      ^^^^^      
+>a : number
+>  : ^^^^^^
+>b : number
+>  : ^^^^^^
+>c : number
+>  : ^^^^^^
+>d : number
+>  : ^^^^^^
+
+  return a + b + c + d;
+>a + b + c + d : number
+>              : ^^^^^^
+>a + b + c : number
+>          : ^^^^^^
+>a + b : number
+>      : ^^^^^^
+>a : number
+>  : ^^^^^^
+>b : number
+>  : ^^^^^^
+>c : number
+>  : ^^^^^^
+>d : number
+>  : ^^^^^^
+}
+
+const result3 = partialCall3(source3, 1);
+>result3 : (a: number, b: number) => number
+>        : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+>partialCall3(source3, 1) : (a: number, b: number) => number
+>                         : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+>partialCall3 : <T extends readonly any[], U extends readonly any[], R>(f: (...args: [...U, ...T, number]) => R, ...tailArgs: T) => (...headArgs: U) => R
+>             : ^ ^^^^^^^^^              ^^ ^^^^^^^^^              ^^ ^^ ^^                                    ^^^^^        ^^ ^^^^^^              ^^^^^^
+>source3 : (a: number, b: number, c: number, d: number) => number
+>        : ^ ^^      ^^ ^^      ^^ ^^      ^^ ^^      ^^^^^      
+>1 : 1
+>  : ^
+
+export {}
+
diff --git a/tests/cases/conformance/types/tuple/variadicTuples4.ts b/tests/cases/conformance/types/tuple/variadicTuples4.ts
new file mode 100644
index 0000000000000..3b530e85f195f
--- /dev/null
+++ b/tests/cases/conformance/types/tuple/variadicTuples4.ts
@@ -0,0 +1,45 @@
+// @strict: true
+// @noEmit: true
+
+// https://github.com/microsoft/TypeScript/issues/56970
+
+function partialCall1<T extends readonly any[], U extends readonly any[], R>(
+  f: (...args: [...U, ...T]) => R,
+  ...tailArgs: T
+) {
+  return (...headArgs: U) => f(...headArgs, ...tailArgs);
+}
+
+function source1(a: number, b: number, c: number): number {
+  return a + b + c;
+}
+
+const result1 = partialCall1(source1, 1);
+
+function partialCall2<T extends readonly any[], U extends readonly any[], R>(
+  f: (...args: [number, ...U, ...T]) => R,
+  ...tailArgs: T
+) {
+  return (...headArgs: U) => f(0, ...headArgs, ...tailArgs);
+}
+
+function source2(a: number, b: number, c: number, d: number): number {
+  return a + b + c + d;
+}
+
+const result2 = partialCall2(source2, 1);
+
+function partialCall3<T extends readonly any[], U extends readonly any[], R>(
+  f: (...args: [...U, ...T, number]) => R,
+  ...tailArgs: T
+) {
+  return (...headArgs: U) => f(...headArgs, ...tailArgs, 100);
+}
+
+function source3(a: number, b: number, c: number, d: number): number {
+  return a + b + c + d;
+}
+
+const result3 = partialCall3(source3, 1);
+
+export {}