Use helper functions in a few more places

src/compiler/utilities.ts

@@ -4374,6 +4374,11 @@ namespace ts {
         return position >= span.start && position < textSpanEnd(span);
     }
 
+    /* @internal */
+    export function textRangeContainsPositionInclusive(span: TextRange, position: number): boolean {
+        return position >= span.pos && position <= span.end;
+    }
+
     // Returns true if 'span' contains 'other'.
     export function textSpanContainsTextSpan(span: TextSpan, other: TextSpan) {
         return other.start >= span.start && textSpanEnd(other) <= textSpanEnd(span);

src/services/goToDefinition.ts

@@ -271,7 +271,7 @@ namespace ts.GoToDefinition {
     }
 
     export function findReferenceInPosition(refs: ReadonlyArray<FileReference>, pos: number): FileReference | undefined {
-        return find(refs, ref => ref.pos <= pos && pos <= ref.end);
+        return find(refs, ref => textRangeContainsPositionInclusive(ref, pos));
     }
 
     function getDefinitionInfoForFileReference(name: string, targetFileName: string): DefinitionInfo {

src/services/utilities.ts

@@ -729,21 +729,14 @@ namespace ts {
                 // this is token that starts at the end of previous token - return it
                 return n;
             }
-
-            const children = n.getChildren();
-            for (const child of children) {
+            return firstDefined(n.getChildren(), child => {
                 const shouldDiveInChildNode =
                     // previous token is enclosed somewhere in the child
                     (child.pos <= previousToken.pos && child.end > previousToken.end) ||
                     // previous token ends exactly at the beginning of child
                     (child.pos === previousToken.end);
-
-                if (shouldDiveInChildNode && nodeHasTokens(child, sourceFile)) {
-                    return find(child);
-                }
-            }
-
-            return undefined;
+                return shouldDiveInChildNode && nodeHasTokens(child, sourceFile) ? find(child) : undefined;
+            });
         }
     }
 

tests/baselines/reference/api/tsserverlibrary.d.ts

@@ -6627,6 +6627,7 @@ declare namespace ts {
     function textSpanEnd(span: TextSpan): number;
     function textSpanIsEmpty(span: TextSpan): boolean;
     function textSpanContainsPosition(span: TextSpan, position: number): boolean;
+    function textRangeContainsPositionInclusive(span: TextRange, position: number): boolean;
     function textSpanContainsTextSpan(span: TextSpan, other: TextSpan): boolean;
     function textSpanOverlapsWith(span: TextSpan, other: TextSpan): boolean;
     function textSpanOverlap(span1: TextSpan, span2: TextSpan): TextSpan | undefined;