Fix JSDoc comment of elided import being preserved in declaration emit (#3963)

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: jakebailey <5341706+jakebailey@users.noreply.github.com>

Author: Copilot

internal/printer/printer.go

@@ -5671,10 +5671,7 @@ func (p *Printer) emitDetachedComments(textRange core.TextRange) (result detache
 				}
 			}
 
-			if p.shouldWriteComment(comment) {
-				detachedComments = append(detachedComments, comment)
-			}
-
+			detachedComments = append(detachedComments, comment)
 			lastComment = comment
 		}
 
@@ -5687,11 +5684,21 @@ func (p *Printer) emitDetachedComments(textRange core.TextRange) (result detache
 			if nodeLine >= lastCommentLine+2 {
 				// Valid detachedComments
 
-				if len(leadingComments) > 0 && p.shouldEmitNewLineBeforeLeadingCommentOfPosition(textRange.Pos(), leadingComments[0].Pos()) {
-					p.writeLine()
+				// Filter to only comments that should be written (e.g., JSDoc-style in declaration emit)
+				var commentsToEmit []ast.CommentRange
+				for _, comment := range detachedComments {
+					if p.shouldWriteComment(comment) {
+						commentsToEmit = append(commentsToEmit, comment)
+					}
 				}
 
-				p.emitComments(detachedComments, commentSeparatorAfter)
+				if len(commentsToEmit) > 0 {
+					if p.shouldEmitNewLineBeforeLeadingCommentOfPosition(textRange.Pos(), commentsToEmit[0].Pos()) {
+						p.writeLine()
+					}
+
+					p.emitComments(commentsToEmit, commentSeparatorAfter)
+				}
 				result = detachedCommentsInfo{nodePos: textRange.Pos(), detachedCommentEndPos: core.LastOrNil(detachedComments).End()}
 				hasResult = true
 			}

testdata/baselines/reference/compiler/jsDocCommentOfElidedImportPreserved.js

@@ -0,0 +1,54 @@
+//// [tests/cases/compiler/jsDocCommentOfElidedImportPreserved.ts] ////
+
+//// [index.ts]
+export interface Foo {}
+
+//// [main.ts]
+/**
+ * Some random docs not related to foo
+ */
+/* trigger */
+import * as x from './index.js';
+export const foo = 1;
+
+//// [detachedCopyright.ts]
+/**
+ * Copyright header
+ */
+
+import * as x from './index.js';
+export const bar = 2;
+
+//// [detachedCopyrightNonJSDoc.ts]
+/* Non-JSDoc copyright header */
+
+import * as x from './index.js';
+export const baz = 3;
+
+
+//// [index.js]
+export {};
+//// [main.js]
+export const foo = 1;
+//// [detachedCopyright.js]
+/**
+ * Copyright header
+ */
+export const bar = 2;
+//// [detachedCopyrightNonJSDoc.js]
+/* Non-JSDoc copyright header */
+export const baz = 3;
+
+
+//// [index.d.ts]
+export interface Foo {
+}
+//// [main.d.ts]
+export declare const foo = 1;
+//// [detachedCopyright.d.ts]
+/**
+ * Copyright header
+ */
+export declare const bar = 2;
+//// [detachedCopyrightNonJSDoc.d.ts]
+export declare const baz = 3;

testdata/baselines/reference/compiler/jsDocCommentOfElidedImportPreserved.symbols

@@ -0,0 +1,37 @@
+//// [tests/cases/compiler/jsDocCommentOfElidedImportPreserved.ts] ////
+
+=== index.ts ===
+export interface Foo {}
+>Foo : Symbol(Foo, Decl(index.ts, 0, 0))
+
+=== main.ts ===
+/**
+ * Some random docs not related to foo
+ */
+/* trigger */
+import * as x from './index.js';
+>x : Symbol(x, Decl(main.ts, 4, 6))
+
+export const foo = 1;
+>foo : Symbol(foo, Decl(main.ts, 5, 12))
+
+=== detachedCopyright.ts ===
+/**
+ * Copyright header
+ */
+
+import * as x from './index.js';
+>x : Symbol(x, Decl(detachedCopyright.ts, 4, 6))
+
+export const bar = 2;
+>bar : Symbol(bar, Decl(detachedCopyright.ts, 5, 12))
+
+=== detachedCopyrightNonJSDoc.ts ===
+/* Non-JSDoc copyright header */
+
+import * as x from './index.js';
+>x : Symbol(x, Decl(detachedCopyrightNonJSDoc.ts, 2, 6))
+
+export const baz = 3;
+>baz : Symbol(baz, Decl(detachedCopyrightNonJSDoc.ts, 3, 12))
+

testdata/baselines/reference/compiler/jsDocCommentOfElidedImportPreserved.types

@@ -0,0 +1,40 @@
+//// [tests/cases/compiler/jsDocCommentOfElidedImportPreserved.ts] ////
+
+=== index.ts ===
+
+export interface Foo {}
+
+=== main.ts ===
+/**
+ * Some random docs not related to foo
+ */
+/* trigger */
+import * as x from './index.js';
+>x : typeof x
+
+export const foo = 1;
+>foo : 1
+>1 : 1
+
+=== detachedCopyright.ts ===
+/**
+ * Copyright header
+ */
+
+import * as x from './index.js';
+>x : typeof x
+
+export const bar = 2;
+>bar : 2
+>2 : 2
+
+=== detachedCopyrightNonJSDoc.ts ===
+/* Non-JSDoc copyright header */
+
+import * as x from './index.js';
+>x : typeof x
+
+export const baz = 3;
+>baz : 3
+>3 : 3
+

testdata/tests/cases/compiler/jsDocCommentOfElidedImportPreserved.ts

@@ -0,0 +1,26 @@
+// @declaration: true
+
+// @filename: index.ts
+export interface Foo {}
+
+// @filename: main.ts
+/**
+ * Some random docs not related to foo
+ */
+/* trigger */
+import * as x from './index.js';
+export const foo = 1;
+
+// @filename: detachedCopyright.ts
+/**
+ * Copyright header
+ */
+
+import * as x from './index.js';
+export const bar = 2;
+
+// @filename: detachedCopyrightNonJSDoc.ts
+/* Non-JSDoc copyright header */
+
+import * as x from './index.js';
+export const baz = 3;