Remove redundant checks in getNameOfDeclaration (microsoft#25244)

Author: Andy

src/compiler/checker.ts

@@ -8807,7 +8807,7 @@ namespace ts {
             if (!(getDeclarationModifierFlagsFromSymbol(prop) & ModifierFlags.NonPublicAccessibilityModifier)) {
                 let type = getLateBoundSymbol(prop).nameType;
                 if (!type && !isKnownSymbol(prop)) {
-                    const name = getNameOfDeclaration(prop.valueDeclaration);
+                    const name = prop.valueDeclaration && getNameOfDeclaration(prop.valueDeclaration);
                     type = name && isNumericLiteral(name) ? getLiteralType(+name.text) :
                         name && name.kind === SyntaxKind.ComputedPropertyName && isNumericLiteral(name.expression) ? getLiteralType(+name.expression.text) :
                         getLiteralType(symbolName(prop));
@@ -23244,7 +23244,7 @@ namespace ts {
                     }
                     else {
                         const parameter = local.valueDeclaration && tryGetRootParameterDeclaration(local.valueDeclaration);
-                        const name = getNameOfDeclaration(local.valueDeclaration);
+                        const name = local.valueDeclaration && getNameOfDeclaration(local.valueDeclaration);
                         if (parameter && name) {
                             if (!isParameterPropertyDeclaration(parameter) && !parameterIsThisKeyword(parameter) && !isIdentifierThatStartsWithUnderscore(name)) {
                                 addDiagnostic(UnusedKind.Parameter, createDiagnosticForNode(name, Diagnostics._0_is_declared_but_its_value_is_never_read, symbolName(local)));
@@ -24541,7 +24541,7 @@ namespace ts {
                 }
 
                 const propDeclaration = prop.valueDeclaration;
-                const name = getNameOfDeclaration(propDeclaration);
+                const name = propDeclaration && getNameOfDeclaration(propDeclaration);
 
                 // index is numeric and property name is not valid numeric literal
                 if (indexKind === IndexKind.Number && !(name ? isNumericName(name) : isNumericLiteralName(prop.escapedName))) {

src/compiler/utilities.ts

@@ -4875,9 +4875,6 @@ namespace ts {
     }
 
     export function getNameOfDeclaration(declaration: Declaration | Expression): DeclarationName | undefined {
-        if (!declaration) {
-            return undefined;
-        }
         switch (declaration.kind) {
             case SyntaxKind.ClassExpression:
             case SyntaxKind.FunctionExpression:
@@ -4907,8 +4904,6 @@ namespace ts {
                         return undefined;
                 }
             }
-            case SyntaxKind.JSDocCallbackTag:
-                return (declaration as JSDocCallbackTag).name;
             case SyntaxKind.JSDocTypedefTag:
                 return getNameOfJSDocTypedef(declaration as JSDocTypedefTag);
             case SyntaxKind.ExportAssignment: {

src/services/codefixes/inferFromUsage.ts

@@ -33,7 +33,7 @@ namespace ts.codefix {
             const token = getTokenAtPosition(sourceFile, start);
             let declaration!: Declaration | undefined;
             const changes = textChanges.ChangeTracker.with(context, changes => { declaration = doChange(changes, sourceFile, token, errorCode, program, cancellationToken, /*markSeenseen*/ returnTrue); });
-            const name = getNameOfDeclaration(declaration!);
+            const name = declaration && getNameOfDeclaration(declaration);
             return !name || changes.length === 0 ? undefined
                 : [createCodeFixAction(fixId, changes, [getDiagnostic(errorCode, token), name.getText(sourceFile)], fixId, Diagnostics.Infer_all_types_from_usage)];
         },

src/services/findAllReferences.ts

@@ -1023,7 +1023,7 @@ namespace ts.FindAllReferences.Core {
 
     function getReferenceForShorthandProperty({ flags, valueDeclaration }: Symbol, search: Search, state: State): void {
         const shorthandValueSymbol = state.checker.getShorthandAssignmentValueSymbol(valueDeclaration)!;
-        const name = getNameOfDeclaration(valueDeclaration);
+        const name = valueDeclaration && getNameOfDeclaration(valueDeclaration);
         /*
          * Because in short-hand property assignment, an identifier which stored as name of the short-hand property assignment
          * has two meanings: property name and property value. Therefore when we do findAllReference at the position where