example.cs

using System;
using System.IO;
using System.Threading.Tasks;

public static class C {
    public static (int, int) GetThing() => (1, 2);
    public static void A1() {
        GetThing();
    }
    
    public static void A2() {
        (_, _) = GetThing();
    }
    
    public static void B1() {
        var (a, b) = GetThing();
        Console.WriteLine(a);
    }
    
    public static void B2() {
        var (a, _) = GetThing();
        Console.WriteLine(a);
    }
}

output.il

.class private auto ansi '<Module>'
{
} // end of class <Module>

.class public auto ansi abstract sealed beforefieldinit C
    extends [System.Private.CoreLib]System.Object
{
    // Methods
    .method public hidebysig static 
        valuetype [System.Private.CoreLib]System.ValueTuple`2<int32, int32> GetThing () cil managed 
    {
        // Method begins at RVA 0x2050
        // Code size 8 (0x8)
        .maxstack 8

        IL_0000: ldc.i4.1
        IL_0001: ldc.i4.2
        IL_0002: newobj instance void valuetype [System.Private.CoreLib]System.ValueTuple`2<int32, int32>::.ctor(!0, !1)
        IL_0007: ret
    } // end of method C::GetThing

    .method public hidebysig static 
        void A1 () cil managed 
    {
        // Method begins at RVA 0x2059
        // Code size 7 (0x7)
        .maxstack 8

        IL_0000: call valuetype [System.Private.CoreLib]System.ValueTuple`2<int32, int32> C::GetThing()
        IL_0005: pop
        IL_0006: ret
    } // end of method C::A1

    .method public hidebysig static 
        void A2 () cil managed 
    {
        // Method begins at RVA 0x2059
        // Code size 7 (0x7)
        .maxstack 8

        IL_0000: call valuetype [System.Private.CoreLib]System.ValueTuple`2<int32, int32> C::GetThing()
        IL_0005: pop
        IL_0006: ret
    } // end of method C::A2

    .method public hidebysig static 
        void B1 () cil managed 
    {
        // Method begins at RVA 0x2064
        // Code size 20 (0x14)
        .maxstack 2
        .locals init (
            [0] int32 a
        )

        IL_0000: call valuetype [System.Private.CoreLib]System.ValueTuple`2<int32, int32> C::GetThing()
        IL_0005: dup
        IL_0006: ldfld !0 valuetype [System.Private.CoreLib]System.ValueTuple`2<int32, int32>::Item1
        IL_000b: stloc.0
        IL_000c: pop
        IL_000d: ldloc.0
        IL_000e: call void [System.Console]System.Console::WriteLine(int32)
        IL_0013: ret
    } // end of method C::B1

    .method public hidebysig static 
        void B2 () cil managed 
    {
        // Method begins at RVA 0x2084
        // Code size 16 (0x10)
        .maxstack 8

        IL_0000: call valuetype [System.Private.CoreLib]System.ValueTuple`2<int32, int32> C::GetThing()
        IL_0005: ldfld !0 valuetype [System.Private.CoreLib]System.ValueTuple`2<int32, int32>::Item1
        IL_000a: call void [System.Console]System.Console::WriteLine(int32)
        IL_000f: ret
    } // end of method C::B2

} // end of class C