fix(50077): skip convertOverloadListToSingleSignature refactoring if position is in function body (microsoft#50093)

Author: a-tarasyuk

src/services/refactors/convertOverloadListToSingleSignature.ts

@@ -185,6 +185,10 @@ ${newComment.split("\n").map(c => ` * ${c}`).join("\n")}
         if (!containingDecl) {
             return;
         }
+        if (isFunctionLikeDeclaration(containingDecl) && containingDecl.body && rangeContainsPosition(containingDecl.body, startPosition)) {
+            return;
+        }
+
         const checker = program.getTypeChecker();
         const signatureSymbol = containingDecl.symbol;
         if (!signatureSymbol) {

tests/cases/fourslash/refactorOverloadListToSingleSignature9.ts

@@ -0,0 +1,22 @@
+/// <reference path="fourslash.ts" />
+
+/////*a1*/function foo(a: string): void;
+/////*a2*/function foo(a: number): void;/*b2*/
+/////*a3*/function foo(a: number | string): void/*b3*/ /*a4*/{
+////    /*a5*/console.log(1);/*b5*/
+////}/*b4*//*b1*/
+
+goTo.select("a1", "b1");
+verify.refactorAvailable("Convert overload list to single signature", "Convert overload list to single signature", ts.Diagnostics.Convert_overload_list_to_single_signature.message);
+
+goTo.select("a2", "b2");
+verify.refactorAvailable("Convert overload list to single signature", "Convert overload list to single signature", ts.Diagnostics.Convert_overload_list_to_single_signature.message);
+
+goTo.select("a3", "b3");
+verify.refactorAvailable("Convert overload list to single signature", "Convert overload list to single signature", ts.Diagnostics.Convert_overload_list_to_single_signature.message);
+
+goTo.select("a4", "b4");
+verify.not.refactorAvailable("Convert overload list to single signature", "Convert overload list to single signature", ts.Diagnostics.Convert_overload_list_to_single_signature.message);
+
+goTo.select("a5", "b5");
+verify.not.refactorAvailable("Convert overload list to single signature", "Convert overload list to single signature", ts.Diagnostics.Convert_overload_list_to_single_signature.message);