Fix jsx element parsing within ternary (microsoft#24149)

weswigham · web-flow · commit 60df4671d04f · 2018-05-16T09:28:22.000-07:00
diff --git a/src/compiler/parser.ts b/src/compiler/parser.ts
@@ -2436,20 +2436,24 @@ namespace ts {
             return finishNode(node);
         }
 
+        /**
+         * @returns If return type parsing succeeds
+         */
         function fillSignature(
             returnToken: SyntaxKind.ColonToken | SyntaxKind.EqualsGreaterThanToken,
             flags: SignatureFlags,
-            signature: SignatureDeclaration): void {
+            signature: SignatureDeclaration): boolean {
             if (!(flags & SignatureFlags.JSDoc)) {
                 signature.typeParameters = parseTypeParameters();
             }
             signature.parameters = parseParameterList(flags);
-            signature.type = parseReturnType(returnToken, !!(flags & SignatureFlags.Type));
+            if (shouldParseReturnType(returnToken, !!(flags & SignatureFlags.Type))) {
+                signature.type = parseTypeOrTypePredicate();
+                return signature.type !== undefined;
+            }
+            return true;
         }
 
-        function parseReturnType(returnToken: SyntaxKind.ColonToken | SyntaxKind.EqualsGreaterThanToken, isType: boolean): TypeNode | undefined {
-            return shouldParseReturnType(returnToken, isType) ? parseTypeOrTypePredicate() : undefined;
-        }
         function shouldParseReturnType(returnToken: SyntaxKind.ColonToken | SyntaxKind.EqualsGreaterThanToken, isType: boolean): boolean {
             if (returnToken === SyntaxKind.EqualsGreaterThanToken) {
                 parseExpected(returnToken);
@@ -2758,6 +2762,9 @@ namespace ts {
             const node = <ParenthesizedTypeNode>createNode(SyntaxKind.ParenthesizedType);
             parseExpected(SyntaxKind.OpenParenToken);
             node.type = parseType();
+            if (!node.type) {
+                return undefined;
+            }
             parseExpected(SyntaxKind.CloseParenToken);
             return finishNode(node);
         }
@@ -2767,7 +2774,12 @@ namespace ts {
             if (kind === SyntaxKind.ConstructorType) {
                 parseExpected(SyntaxKind.NewKeyword);
             }
-            fillSignature(SyntaxKind.EqualsGreaterThanToken, SignatureFlags.Type, node);
+            if (!fillSignature(SyntaxKind.EqualsGreaterThanToken, SignatureFlags.Type | (sourceFile.languageVariant === LanguageVariant.JSX ? SignatureFlags.RequireCompleteParameterList : 0), node)) {
+                return undefined;
+            }
+            if (!node.parameters) {
+                return undefined;
+            }
             return finishNode(node);
         }
 
@@ -3598,7 +3610,9 @@ namespace ts {
             // a => (b => c)
             // And think that "(b =>" was actually a parenthesized arrow function with a missing
             // close paren.
-            fillSignature(SyntaxKind.ColonToken, isAsync | (allowAmbiguity ? SignatureFlags.None : SignatureFlags.RequireCompleteParameterList), node);
+            if (!fillSignature(SyntaxKind.ColonToken, isAsync | (allowAmbiguity ? SignatureFlags.None : SignatureFlags.RequireCompleteParameterList), node)) {
+                return undefined;
+            }
 
             // If we couldn't get parameters, we definitely could not parse out an arrow function.
             if (!node.parameters) {
diff --git a/tests/baselines/reference/jsxNestedWithinTernaryParsesCorrectly.js b/tests/baselines/reference/jsxNestedWithinTernaryParsesCorrectly.js
@@ -0,0 +1,25 @@
+//// [jsxNestedWithinTernaryParsesCorrectly.tsx]
+const emptyMessage = null as any;
+const a = (
+    <div>
+      {0 ? (
+        emptyMessage // must be identifier?
+      ) : (
+          // must be exactly two expression holes
+        <span>
+          {0}{0}
+        </span>
+      )}
+    </div>
+);
+
+//// [jsxNestedWithinTernaryParsesCorrectly.jsx]
+var emptyMessage = null;
+var a = (<div>
+      {0 ? (emptyMessage // must be identifier?
+) : (
+// must be exactly two expression holes
+<span>
+          {0}{0}
+        </span>)}
+    </div>);
diff --git a/tests/baselines/reference/jsxNestedWithinTernaryParsesCorrectly.symbols b/tests/baselines/reference/jsxNestedWithinTernaryParsesCorrectly.symbols
@@ -0,0 +1,20 @@
+=== tests/cases/compiler/jsxNestedWithinTernaryParsesCorrectly.tsx ===
+const emptyMessage = null as any;
+>emptyMessage : Symbol(emptyMessage, Decl(jsxNestedWithinTernaryParsesCorrectly.tsx, 0, 5))
+
+const a = (
+>a : Symbol(a, Decl(jsxNestedWithinTernaryParsesCorrectly.tsx, 1, 5))
+
+    <div>
+      {0 ? (
+        emptyMessage // must be identifier?
+>emptyMessage : Symbol(emptyMessage, Decl(jsxNestedWithinTernaryParsesCorrectly.tsx, 0, 5))
+
+      ) : (
+          // must be exactly two expression holes
+        <span>
+          {0}{0}
+        </span>
+      )}
+    </div>
+);
diff --git a/tests/baselines/reference/jsxNestedWithinTernaryParsesCorrectly.types b/tests/baselines/reference/jsxNestedWithinTernaryParsesCorrectly.types
@@ -0,0 +1,42 @@
+=== tests/cases/compiler/jsxNestedWithinTernaryParsesCorrectly.tsx ===
+const emptyMessage = null as any;
+>emptyMessage : any
+>null as any : any
+>null : null
+
+const a = (
+>a : any
+>(    <div>      {0 ? (        emptyMessage // must be identifier?      ) : (          // must be exactly two expression holes        <span>          {0}{0}        </span>      )}    </div>) : any
+
+    <div>
+><div>      {0 ? (        emptyMessage // must be identifier?      ) : (          // must be exactly two expression holes        <span>          {0}{0}        </span>      )}    </div> : any
+>div : any
+
+      {0 ? (
+>0 ? (        emptyMessage // must be identifier?      ) : (          // must be exactly two expression holes        <span>          {0}{0}        </span>      ) : any
+>0 : 0
+>(        emptyMessage // must be identifier?      ) : any
+
+        emptyMessage // must be identifier?
+>emptyMessage : any
+
+      ) : (
+>(          // must be exactly two expression holes        <span>          {0}{0}        </span>      ) : any
+
+          // must be exactly two expression holes
+        <span>
+><span>          {0}{0}        </span> : any
+>span : any
+
+          {0}{0}
+>0 : 0
+>0 : 0
+
+        </span>
+>span : any
+
+      )}
+    </div>
+>div : any
+
+);
diff --git a/tests/cases/compiler/jsxNestedWithinTernaryParsesCorrectly.tsx b/tests/cases/compiler/jsxNestedWithinTernaryParsesCorrectly.tsx
@@ -0,0 +1,14 @@
+// @jsx: preserve
+const emptyMessage = null as any;
+const a = (
+    <div>
+      {0 ? (
+        emptyMessage // must be identifier?
+      ) : (
+          // must be exactly two expression holes
+        <span>
+          {0}{0}
+        </span>
+      )}
+    </div>
+);
