From 0ef9e8eac9cedfaadc3f9072313cdea78472a2d5 Mon Sep 17 00:00:00 2001
From: Jake Bailey <5341706+jakebailey@users.noreply.github.com>
Date: Thu, 9 Feb 2023 11:34:47 -0800
Subject: [PATCH] Ensure we treat "type assertions" as JSX within a unary
 expression (#52667)

---
 src/compiler/parser.ts                        |  6 +++++
 ...ExpressionNoTypeAssertionInJsx1.errors.txt | 15 ++++++++++++
 ...aryExpressionNoTypeAssertionInJsx1.symbols |  7 ++++++
 ...UnaryExpressionNoTypeAssertionInJsx1.types | 13 ++++++++++
 ...ExpressionNoTypeAssertionInJsx2.errors.txt | 15 ++++++++++++
 ...aryExpressionNoTypeAssertionInJsx2.symbols |  7 ++++++
 ...UnaryExpressionNoTypeAssertionInJsx2.types | 10 ++++++++
 ...ExpressionNoTypeAssertionInJsx3.errors.txt | 15 ++++++++++++
 ...aryExpressionNoTypeAssertionInJsx3.symbols |  8 +++++++
 ...UnaryExpressionNoTypeAssertionInJsx3.types | 14 +++++++++++
 ...ExpressionNoTypeAssertionInJsx4.errors.txt | 24 +++++++++++++++++++
 ...rseUnaryExpressionNoTypeAssertionInJsx4.js | 14 +++++++++++
 ...aryExpressionNoTypeAssertionInJsx4.symbols | 10 ++++++++
 ...UnaryExpressionNoTypeAssertionInJsx4.types | 20 ++++++++++++++++
 ...rseUnaryExpressionNoTypeAssertionInJsx1.ts |  7 ++++++
 ...rseUnaryExpressionNoTypeAssertionInJsx2.ts |  7 ++++++
 ...rseUnaryExpressionNoTypeAssertionInJsx3.ts |  7 ++++++
 ...rseUnaryExpressionNoTypeAssertionInJsx4.ts |  8 +++++++
 18 files changed, 207 insertions(+)
 create mode 100644 tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx1.errors.txt
 create mode 100644 tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx1.symbols
 create mode 100644 tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx1.types
 create mode 100644 tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx2.errors.txt
 create mode 100644 tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx2.symbols
 create mode 100644 tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx2.types
 create mode 100644 tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx3.errors.txt
 create mode 100644 tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx3.symbols
 create mode 100644 tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx3.types
 create mode 100644 tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx4.errors.txt
 create mode 100644 tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx4.js
 create mode 100644 tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx4.symbols
 create mode 100644 tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx4.types
 create mode 100644 tests/cases/compiler/parseUnaryExpressionNoTypeAssertionInJsx1.ts
 create mode 100644 tests/cases/compiler/parseUnaryExpressionNoTypeAssertionInJsx2.ts
 create mode 100644 tests/cases/compiler/parseUnaryExpressionNoTypeAssertionInJsx3.ts
 create mode 100644 tests/cases/compiler/parseUnaryExpressionNoTypeAssertionInJsx4.ts

diff --git a/src/compiler/parser.ts b/src/compiler/parser.ts
index 0baf8b65bc4..4763040626b 100644
--- a/src/compiler/parser.ts
+++ b/src/compiler/parser.ts
@@ -5648,6 +5648,11 @@ namespace Parser {
             case SyntaxKind.VoidKeyword:
                 return parseVoidExpression();
             case SyntaxKind.LessThanToken:
+                // Just like in parseUpdateExpression, we need to avoid parsing type assertions when
+                // in JSX and we see an expression like "+ <foo> bar".
+                if (languageVariant === LanguageVariant.JSX) {
+                    return parseJsxElementOrSelfClosingElementOrFragment(/*inExpressionContext*/ true);
+                }
                 // This is modified UnaryExpression grammar in TypeScript
                 //  UnaryExpression (modified):
                 //      < type > UnaryExpression
@@ -6163,6 +6168,7 @@ namespace Parser {
     }
 
     function parseTypeAssertion(): TypeAssertion {
+        Debug.assert(scriptKind === ScriptKind.TS, "Type assertions should never be parsed outside of TS; they should either be comparisons or JSX.");
         const pos = getNodePos();
         parseExpected(SyntaxKind.LessThanToken);
         const type = parseType();
diff --git a/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx1.errors.txt b/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx1.errors.txt
new file mode 100644
index 00000000000..6a77ea5512e
--- /dev/null
+++ b/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx1.errors.txt
@@ -0,0 +1,15 @@
+tests/cases/compiler/index.js(2,13): error TS17004: Cannot use JSX unless the '--jsx' flag is provided.
+tests/cases/compiler/index.js(2,14): error TS17008: JSX element 'number' has no corresponding closing tag.
+tests/cases/compiler/index.js(3,1): error TS1005: '</' expected.
+
+
+==== tests/cases/compiler/index.js (3 errors) ====
+    const x = "oops";
+    const y = + <number> x;
+                ~~~~~~~~
+!!! error TS17004: Cannot use JSX unless the '--jsx' flag is provided.
+                 ~~~~~~
+!!! error TS17008: JSX element 'number' has no corresponding closing tag.
+    
+    
+!!! error TS1005: '</' expected.
\ No newline at end of file
diff --git a/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx1.symbols b/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx1.symbols
new file mode 100644
index 00000000000..b9c72253e9a
--- /dev/null
+++ b/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx1.symbols
@@ -0,0 +1,7 @@
+=== tests/cases/compiler/index.js ===
+const x = "oops";
+>x : Symbol(x, Decl(index.js, 0, 5))
+
+const y = + <number> x;
+>y : Symbol(y, Decl(index.js, 1, 5))
+
diff --git a/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx1.types b/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx1.types
new file mode 100644
index 00000000000..e2d8b7e2fec
--- /dev/null
+++ b/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx1.types
@@ -0,0 +1,13 @@
+=== tests/cases/compiler/index.js ===
+const x = "oops";
+>x : "oops"
+>"oops" : "oops"
+
+const y = + <number> x;
+>y : number
+>+ <number> x; : number
+><number> x; : any
+>number : any
+
+> : any
+
diff --git a/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx2.errors.txt b/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx2.errors.txt
new file mode 100644
index 00000000000..b1acc4a4774
--- /dev/null
+++ b/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx2.errors.txt
@@ -0,0 +1,15 @@
+tests/cases/compiler/index.js(2,12): error TS17014: JSX fragment has no corresponding closing tag.
+tests/cases/compiler/index.js(2,13): error TS17004: Cannot use JSX unless the '--jsx' flag is provided.
+tests/cases/compiler/index.js(3,1): error TS1005: '</' expected.
+
+
+==== tests/cases/compiler/index.js (3 errors) ====
+    const x = "oops";
+    const y = + <> x;
+               ~~~
+!!! error TS17014: JSX fragment has no corresponding closing tag.
+                ~~
+!!! error TS17004: Cannot use JSX unless the '--jsx' flag is provided.
+    
+    
+!!! error TS1005: '</' expected.
\ No newline at end of file
diff --git a/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx2.symbols b/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx2.symbols
new file mode 100644
index 00000000000..0038ff63290
--- /dev/null
+++ b/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx2.symbols
@@ -0,0 +1,7 @@
+=== tests/cases/compiler/index.js ===
+const x = "oops";
+>x : Symbol(x, Decl(index.js, 0, 5))
+
+const y = + <> x;
+>y : Symbol(y, Decl(index.js, 1, 5))
+
diff --git a/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx2.types b/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx2.types
new file mode 100644
index 00000000000..b8a8ef32d64
--- /dev/null
+++ b/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx2.types
@@ -0,0 +1,10 @@
+=== tests/cases/compiler/index.js ===
+const x = "oops";
+>x : "oops"
+>"oops" : "oops"
+
+const y = + <> x;
+>y : number
+>+ <> x; : number
+><> x; : any
+
diff --git a/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx3.errors.txt b/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx3.errors.txt
new file mode 100644
index 00000000000..132f825fe40
--- /dev/null
+++ b/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx3.errors.txt
@@ -0,0 +1,15 @@
+tests/cases/compiler/index.js(2,13): error TS17004: Cannot use JSX unless the '--jsx' flag is provided.
+tests/cases/compiler/index.js(2,14): error TS1003: Identifier expected.
+tests/cases/compiler/index.js(2,14): error TS2365: Operator '>' cannot be applied to types 'number' and 'string'.
+
+
+==== tests/cases/compiler/index.js (3 errors) ====
+    const x = "oops";
+    const y = + <1234> x;
+                ~
+!!! error TS17004: Cannot use JSX unless the '--jsx' flag is provided.
+                 ~~~~
+!!! error TS1003: Identifier expected.
+                 ~~~~~~~
+!!! error TS2365: Operator '>' cannot be applied to types 'number' and 'string'.
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx3.symbols b/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx3.symbols
new file mode 100644
index 00000000000..a8c0e88d945
--- /dev/null
+++ b/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx3.symbols
@@ -0,0 +1,8 @@
+=== tests/cases/compiler/index.js ===
+const x = "oops";
+>x : Symbol(x, Decl(index.js, 0, 5))
+
+const y = + <1234> x;
+>y : Symbol(y, Decl(index.js, 1, 5))
+>x : Symbol(x, Decl(index.js, 0, 5))
+
diff --git a/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx3.types b/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx3.types
new file mode 100644
index 00000000000..9cdbabb588e
--- /dev/null
+++ b/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx3.types
@@ -0,0 +1,14 @@
+=== tests/cases/compiler/index.js ===
+const x = "oops";
+>x : "oops"
+>"oops" : "oops"
+
+const y = + <1234> x;
+>y : number
+>+ < : number
+>< : any
+> : any
+>1234> x : boolean
+>1234 : 1234
+>x : "oops"
+
diff --git a/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx4.errors.txt b/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx4.errors.txt
new file mode 100644
index 00000000000..24710242160
--- /dev/null
+++ b/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx4.errors.txt
@@ -0,0 +1,24 @@
+tests/cases/compiler/index.tsx(3,14): error TS17008: JSX element 'number' has no corresponding closing tag.
+tests/cases/compiler/index.tsx(4,13): error TS17014: JSX fragment has no corresponding closing tag.
+tests/cases/compiler/index.tsx(5,14): error TS1003: Identifier expected.
+tests/cases/compiler/index.tsx(5,18): error TS1382: Unexpected token. Did you mean `{'>'}` or `&gt;`?
+tests/cases/compiler/index.tsx(6,1): error TS1005: '</' expected.
+
+
+==== tests/cases/compiler/index.tsx (5 errors) ====
+    const x = "oops";
+    
+    const a = + <number> x;
+                 ~~~~~~
+!!! error TS17008: JSX element 'number' has no corresponding closing tag.
+    const b = + <> x;
+                ~~
+!!! error TS17014: JSX fragment has no corresponding closing tag.
+    const c = + <1234> x;
+                 ~~~~
+!!! error TS1003: Identifier expected.
+                     ~
+!!! error TS1382: Unexpected token. Did you mean `{'>'}` or `&gt;`?
+    
+    
+!!! error TS1005: '</' expected.
\ No newline at end of file
diff --git a/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx4.js b/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx4.js
new file mode 100644
index 00000000000..61ad18639b9
--- /dev/null
+++ b/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx4.js
@@ -0,0 +1,14 @@
+//// [index.tsx]
+const x = "oops";
+
+const a = + <number> x;
+const b = + <> x;
+const c = + <1234> x;
+
+
+//// [index.jsx]
+var x = "oops";
+var a = +<number> x;
+const b = + <> x;
+const c = + < />1234> x;
+</></>;
diff --git a/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx4.symbols b/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx4.symbols
new file mode 100644
index 00000000000..50a8c1e513c
--- /dev/null
+++ b/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx4.symbols
@@ -0,0 +1,10 @@
+=== tests/cases/compiler/index.tsx ===
+const x = "oops";
+>x : Symbol(x, Decl(index.tsx, 0, 5))
+
+const a = + <number> x;
+>a : Symbol(a, Decl(index.tsx, 2, 5))
+
+const b = + <> x;
+const c = + <1234> x;
+
diff --git a/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx4.types b/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx4.types
new file mode 100644
index 00000000000..e0e0c0d4d64
--- /dev/null
+++ b/tests/baselines/reference/parseUnaryExpressionNoTypeAssertionInJsx4.types
@@ -0,0 +1,20 @@
+=== tests/cases/compiler/index.tsx ===
+const x = "oops";
+>x : "oops"
+>"oops" : "oops"
+
+const a = + <number> x;
+>a : number
+>+ <number> x;const b = + <> x;const c = + <1234> x; : number
+><number> x;const b = + <> x;const c = + <1234> x; : any
+>number : any
+
+const b = + <> x;
+><> x;const c = + <1234> x; : any
+
+const c = + <1234> x;
+>< : any
+> : any
+
+> : any
+
diff --git a/tests/cases/compiler/parseUnaryExpressionNoTypeAssertionInJsx1.ts b/tests/cases/compiler/parseUnaryExpressionNoTypeAssertionInJsx1.ts
new file mode 100644
index 00000000000..1c9be1bd45a
--- /dev/null
+++ b/tests/cases/compiler/parseUnaryExpressionNoTypeAssertionInJsx1.ts
@@ -0,0 +1,7 @@
+// @allowJs: true
+// @noEmit: true
+// @checkJs: true
+// @filename: index.js
+
+const x = "oops";
+const y = + <number> x;
diff --git a/tests/cases/compiler/parseUnaryExpressionNoTypeAssertionInJsx2.ts b/tests/cases/compiler/parseUnaryExpressionNoTypeAssertionInJsx2.ts
new file mode 100644
index 00000000000..1b6b86d830d
--- /dev/null
+++ b/tests/cases/compiler/parseUnaryExpressionNoTypeAssertionInJsx2.ts
@@ -0,0 +1,7 @@
+// @allowJs: true
+// @noEmit: true
+// @checkJs: true
+// @filename: index.js
+
+const x = "oops";
+const y = + <> x;
diff --git a/tests/cases/compiler/parseUnaryExpressionNoTypeAssertionInJsx3.ts b/tests/cases/compiler/parseUnaryExpressionNoTypeAssertionInJsx3.ts
new file mode 100644
index 00000000000..09407f0a85f
--- /dev/null
+++ b/tests/cases/compiler/parseUnaryExpressionNoTypeAssertionInJsx3.ts
@@ -0,0 +1,7 @@
+// @allowJs: true
+// @noEmit: true
+// @checkJs: true
+// @filename: index.js
+
+const x = "oops";
+const y = + <1234> x;
diff --git a/tests/cases/compiler/parseUnaryExpressionNoTypeAssertionInJsx4.ts b/tests/cases/compiler/parseUnaryExpressionNoTypeAssertionInJsx4.ts
new file mode 100644
index 00000000000..4f892516d10
--- /dev/null
+++ b/tests/cases/compiler/parseUnaryExpressionNoTypeAssertionInJsx4.ts
@@ -0,0 +1,8 @@
+// @filename: index.tsx
+// @jsx: preserve
+
+const x = "oops";
+
+const a = + <number> x;
+const b = + <> x;
+const c = + <1234> x;