fix(45336): add a blank line before the comment expression to avoid disrupting return statement (#46287)

src/compiler/transformers/es2015.ts

@@ -4147,7 +4147,8 @@ namespace ts {
             // NoSubstitutionTemplateLiterals are directly emitted via emitLiteral()
             Debug.assert(node.templateSpans.length !== 0);
 
-            return node.head.text.length !== 0 || node.templateSpans[0].literal.text.length === 0;
+            const span = node.templateSpans[0];
+            return node.head.text.length !== 0 || span.literal.text.length === 0 || !!length(getLeadingCommentRangesOfNode(span.expression, currentSourceFile));
         }
 
         /**

tests/baselines/reference/templateStringWithCommentsInArrowFunction.js

@@ -0,0 +1,27 @@
+//// [templateStringWithCommentsInArrowFunction.ts]
+const a = 1;
+const f1 = () =>
+    `${
+      // a
+      a
+    }a`;
+
+const f2 = () =>
+    `${
+      // a
+      a
+    }`;
+
+
+//// [templateStringWithCommentsInArrowFunction.js]
+var a = 1;
+var f1 = function () {
+    return "" + 
+    // a
+    a + "a";
+};
+var f2 = function () {
+    return "" + 
+    // a
+    a;
+};

tests/baselines/reference/templateStringWithCommentsInArrowFunction.symbols

@@ -0,0 +1,24 @@
+=== tests/cases/conformance/es6/templates/templateStringWithCommentsInArrowFunction.ts ===
+const a = 1;
+>a : Symbol(a, Decl(templateStringWithCommentsInArrowFunction.ts, 0, 5))
+
+const f1 = () =>
+>f1 : Symbol(f1, Decl(templateStringWithCommentsInArrowFunction.ts, 1, 5))
+
+    `${
+      // a
+      a
+>a : Symbol(a, Decl(templateStringWithCommentsInArrowFunction.ts, 0, 5))
+
+    }a`;
+
+const f2 = () =>
+>f2 : Symbol(f2, Decl(templateStringWithCommentsInArrowFunction.ts, 7, 5))
+
+    `${
+      // a
+      a
+>a : Symbol(a, Decl(templateStringWithCommentsInArrowFunction.ts, 0, 5))
+
+    }`;
+

tests/baselines/reference/templateStringWithCommentsInArrowFunction.types

@@ -0,0 +1,31 @@
+=== tests/cases/conformance/es6/templates/templateStringWithCommentsInArrowFunction.ts ===
+const a = 1;
+>a : 1
+>1 : 1
+
+const f1 = () =>
+>f1 : () => string
+>() =>    `${      // a      a    }a` : () => string
+
+    `${
+>`${      // a      a    }a` : string
+
+      // a
+      a
+>a : 1
+
+    }a`;
+
+const f2 = () =>
+>f2 : () => string
+>() =>    `${      // a      a    }` : () => string
+
+    `${
+>`${      // a      a    }` : string
+
+      // a
+      a
+>a : 1
+
+    }`;
+

tests/cases/conformance/es6/templates/templateStringWithCommentsInArrowFunction.ts

@@ -0,0 +1,14 @@
+// @removeComments: false
+
+const a = 1;
+const f1 = () =>
+    `${
+      // a
+      a
+    }a`;
+
+const f2 = () =>
+    `${
+      // a
+      a
+    }`;