[WIP] Port TypeScript PR #60304: More rigorous ASI prevention when emitting return/yield

internal/printer/printer.go

@@ -2949,8 +2949,56 @@ func (p *Printer) emitPartiallyEmittedExpression(node *ast.PartiallyEmittedExpre
 	}
 }
 
+func (p *Printer) commentWillEmitNewLine(comment ast.CommentRange) bool {
+	return comment.Kind == ast.KindSingleLineCommentTrivia || comment.HasTrailingNewLine
+}
+
 func (p *Printer) willEmitLeadingNewLine(node *ast.Expression) bool {
-	return false // !!! check if node will emit a leading comment that contains a trailing newline
+	if p.currentSourceFile == nil {
+		return false
+	}
+
+	text := p.currentSourceFile.Text()
+	pos := node.Pos()
+
+	// Get leading comment ranges
+	var leadingCommentRanges []ast.CommentRange
+	for commentRange := range scanner.GetLeadingCommentRanges(p.emitContext.Factory.AsNodeFactory(), text, pos) {
+		leadingCommentRanges = append(leadingCommentRanges, commentRange)
+	}
+
+	if len(leadingCommentRanges) > 0 {
+		parseNode := p.emitContext.ParseNode(node.AsNode())
+		if parseNode != nil && parseNode.Parent != nil && ast.IsParenthesizedExpression(parseNode.Parent) {
+			return true
+		}
+	}
+
+	// Check if any leading comment will emit a newline
+	for _, comment := range leadingCommentRanges {
+		if p.commentWillEmitNewLine(comment) {
+			return true
+		}
+	}
+
+	// Check synthetic leading comments (currently stubbed out in this codebase)
+	// if some(getSyntheticLeadingComments(node), commentWillEmitNewLine)) return true;
+
+	// Handle PartiallyEmittedExpression recursively
+	if node.Kind == ast.KindPartiallyEmittedExpression {
+		partiallyEmitted := node.AsPartiallyEmittedExpression()
+		if node.Pos() != partiallyEmitted.Expression.Pos() {
+			// Check trailing comments at the expression position
+			for trailingComment := range scanner.GetTrailingCommentRanges(p.emitContext.Factory.AsNodeFactory(), text, partiallyEmitted.Expression.Pos()) {
+				if p.commentWillEmitNewLine(trailingComment) {
+					return true
+				}
+			}
+		}
+		return p.willEmitLeadingNewLine(partiallyEmitted.Expression)
+	}
+
+	return false
 }
 
 func (p *Printer) emitExpressionNoASI(node *ast.Expression, precedence ast.OperatorPrecedence) {

testdata/baselines/reference/submodule/compiler/commentEmitOnParenthesizedAssertionInReturnStatement.js

@@ -21,8 +21,8 @@ export class Foo {
         getThing: () => Promise.resolve('')
     };
     foo() {
-        return 
-        /* TODO: Avoid using type assertions, please refactor. */ this.client
-            .getThing();
+        return (
+        /* TODO: Avoid using type assertions, please refactor. */ (this.client
+            .getThing()));
     }
 }

testdata/baselines/reference/submodule/compiler/commentEmitOnParenthesizedAssertionInReturnStatement.js.diff

@@ -1,13 +1,12 @@
 --- old.commentEmitOnParenthesizedAssertionInReturnStatement.js
 +++ new.commentEmitOnParenthesizedAssertionInReturnStatement.js
-@@= skipped -20, +20 lines =@@
-         getThing: () => Promise.resolve('')
+@@= skipped -21, +21 lines =@@
      };
      foo() {
--        return (
-+        return 
-         /* TODO: Avoid using type assertions, please refactor. */ this.client
+         return (
+-        /* TODO: Avoid using type assertions, please refactor. */ this.client
 -            .getThing());
-+            .getThing();
++        /* TODO: Avoid using type assertions, please refactor. */ (this.client
++            .getThing()));
      }
  }

testdata/baselines/reference/submodule/compiler/commentEmitOnParenthesizedAssertionInReturnStatement2.js

@@ -19,8 +19,8 @@ export class Foo {
         getThing: () => Promise.resolve('')
     };
     foo() {
-        return 
-        /* TODO: please refactor */ this.client
-            .getThing();
+        return (
+        /* TODO: please refactor */ (this.client
+            .getThing()));
     }
 }

testdata/baselines/reference/submodule/compiler/commentEmitOnParenthesizedAssertionInReturnStatement2.js.diff

@@ -1,13 +1,12 @@
 --- old.commentEmitOnParenthesizedAssertionInReturnStatement2.js
 +++ new.commentEmitOnParenthesizedAssertionInReturnStatement2.js
-@@= skipped -18, +18 lines =@@
-         getThing: () => Promise.resolve('')
+@@= skipped -19, +19 lines =@@
      };
      foo() {
--        return (
-+        return 
-         /* TODO: please refactor */ this.client
+         return (
+-        /* TODO: please refactor */ this.client
 -            .getThing());
-+            .getThing();
++        /* TODO: please refactor */ (this.client
++            .getThing()));
      }
  }

testdata/baselines/reference/submodule/conformance/returnStatementNoAsiAfterTransform(target=es5).js

@@ -67,9 +67,9 @@ function t10() {
 
 //// [returnStatementNoAsiAfterTransform.js]
 function t1() {
-    return 
+    return (
     // comment
-    a;
+    (a));
 }
 function t2() {
     return 
@@ -102,17 +102,17 @@ function t7() {
     a ``;
 }
 function t8() {
-    return 
+    return (
     // comment
-    a;
+    (a));
 }
 function t9() {
-    return 
+    return (
     // comment
-    a;
+    (a));
 }
 function t10() {
-    return 
+    return (
     // comment
-    a;
+    (a));
 }

testdata/baselines/reference/submodule/conformance/returnStatementNoAsiAfterTransform(target=es5).js.diff

@@ -9,11 +9,10 @@
 -    return cooked;
 -};
  function t1() {
--    return (
-+    return 
+     return (
      // comment
 -    a);
-+    a;
++    (a));
  }
  function t2() {
 -    return (
@@ -58,23 +57,20 @@
 +    a ``;
  }
  function t8() {
--    return (
-+    return 
+     return (
      // comment
 -    a);
-+    a;
++    (a));
  }
  function t9() {
--    return (
-+    return 
+     return (
      // comment
 -    a);
-+    a;
++    (a));
  }
  function t10() {
--    return (
-+    return 
+     return (
      // comment
 -    a);
-+    a;
++    (a));
  }

testdata/baselines/reference/submodule/conformance/returnStatementNoAsiAfterTransform(target=esnext).js

@@ -67,9 +67,9 @@ function t10() {
 
 //// [returnStatementNoAsiAfterTransform.js]
 function t1() {
-    return 
+    return (
     // comment
-    a;
+    (a));
 }
 function t2() {
     return 
@@ -102,17 +102,17 @@ function t7() {
     a ``;
 }
 function t8() {
-    return 
+    return (
     // comment
-    a;
+    (a));
 }
 function t9() {
-    return 
+    return (
     // comment
-    a;
+    (a));
 }
 function t10() {
-    return 
+    return (
     // comment
-    a;
+    (a));
 }

testdata/baselines/reference/submodule/conformance/returnStatementNoAsiAfterTransform(target=esnext).js.diff

@@ -1,14 +1,11 @@
 --- old.returnStatementNoAsiAfterTransform(target=esnext).js
 +++ new.returnStatementNoAsiAfterTransform(target=esnext).js
-@@= skipped -66, +66 lines =@@
-
- //// [returnStatementNoAsiAfterTransform.js]
+@@= skipped -68, +68 lines =@@
  function t1() {
--    return (
-+    return 
+     return (
      // comment
 -    a);
-+    a;
++    (a));
  }
  function t2() {
 -    return (
@@ -53,23 +50,20 @@
 +    a ``;
  }
  function t8() {
--    return (
-+    return 
+     return (
      // comment
 -    a);
-+    a;
++    (a));
  }
  function t9() {
--    return (
-+    return 
+     return (
      // comment
 -    a);
-+    a;
++    (a));
  }
  function t10() {
--    return (
-+    return 
+     return (
      // comment
 -    a);
-+    a;
++    (a));
  }

testdata/baselines/reference/submodule/conformance/yieldStatementNoAsiAfterTransform(target=es5).js

@@ -67,9 +67,9 @@ function *t10() {
 
 //// [yieldStatementNoAsiAfterTransform.js]
 function* t1() {
-    yield 
+    yield (
     // comment
-    a;
+    (a));
 }
 function* t2() {
     yield 
@@ -102,17 +102,17 @@ function* t7() {
     a ``;
 }
 function* t8() {
-    yield 
+    yield (
     // comment
-    a;
+    (a));
 }
 function* t9() {
-    yield 
+    yield (
     // comment
-    a;
+    (a));
 }
 function* t10() {
-    yield 
+    yield (
     // comment
-    a;
+    (a));
 }

testdata/baselines/reference/submodule/conformance/yieldStatementNoAsiAfterTransform(target=es5).js.diff

@@ -155,9 +155,9 @@
 -        }
 -    });
 +function* t1() {
-+    yield 
++    yield (
 +    // comment
-+    a;
++    (a));
 +}
 +function* t2() {
 +    yield 
@@ -190,17 +190,17 @@
 +    a ``;
 +}
 +function* t8() {
-+    yield 
++    yield (
 +    // comment
-+    a;
++    (a));
 +}
 +function* t9() {
-+    yield 
++    yield (
 +    // comment
-+    a;
++    (a));
 +}
 +function* t10() {
-+    yield 
++    yield (
 +    // comment
-+    a;
++    (a));
  }

testdata/baselines/reference/submodule/conformance/yieldStatementNoAsiAfterTransform(target=esnext).js

@@ -67,9 +67,9 @@ function *t10() {
 
 //// [yieldStatementNoAsiAfterTransform.js]
 function* t1() {
-    yield 
+    yield (
     // comment
-    a;
+    (a));
 }
 function* t2() {
     yield 
@@ -102,17 +102,17 @@ function* t7() {
     a ``;
 }
 function* t8() {
-    yield 
+    yield (
     // comment
-    a;
+    (a));
 }
 function* t9() {
-    yield 
+    yield (
     // comment
-    a;
+    (a));
 }
 function* t10() {
-    yield 
+    yield (
     // comment
-    a;
+    (a));
 }