Refine format according to code review

Author: Changqing-JING

src/compiler.ts

@@ -6610,8 +6610,8 @@ export class Compiler extends DiagnosticEmitter {
         let overrideInstance = overrideInstances[i];
         if (!overrideInstance.is(CommonFlags.Compiled)) continue; // errored
 
-        const overrideSignature = overrideInstance.signature;
-        const originalSignature = instance.signature;
+        let overrideSignature = overrideInstance.signature;
+        let originalSignature = instance.signature;
 
         if (!overrideSignature.isAssignableTo(originalSignature, true)) {
           this.error(

src/types.ts

@@ -1052,13 +1052,12 @@ export class Signature {
     let thisThisType = this.thisType;
     let targetThisType = target.thisType;
 
-    if (thisThisType != null && targetThisType != null){
-      const compatibleThisType = checkCompatibleOverride ? thisThisType.canExtendOrImplement(targetThisType)
+    if (thisThisType && targetThisType) {
+      const compatibleThisType = checkCompatibleOverride 
+        ? thisThisType.canExtendOrImplement(targetThisType)
         : targetThisType.isAssignableTo(thisThisType);
-      if (!compatibleThisType) {
-        return false;
-      }
-    }else if (thisThisType || targetThisType){
+      if (!compatibleThisType) return false; 
+    } else if (thisThisType || targetThisType) {
       return false;
     }
 

tests/compiler/class-member-function-as-parameter.ts

@@ -1,14 +1,19 @@
 class A {
   foo(): void { }
 }
+
 class B extends A {
   foo(): void { }
 }
+
 function foo(): void { }
+
 function consumeA(callback: (this: A) => void): void { }
 function consumeB(callback: (this: B) => void): void { }
+
 const a = new A();
 const b = new B();
+
 consumeB(a.foo); // shouldn't error
 consumeA(foo);   // should error
 consumeA(b.foo); // should error