Run ParseDiagnosticGenerator for mutated test cases

Just make sure that we don’t crash the diagnostic generator with the mutated test cases.

Author: ahoppen

Sources/SwiftParser/Nominals.swift

@@ -333,7 +333,7 @@ extension Parser {
   }
 
   mutating func parsePrimaryAssociatedTypes() -> RawPrimaryAssociatedTypeClauseSyntax {
-    let langle = self.consumeAnyToken(remapping: .leftAngle)
+    let langle = self.consumePrefix("<", as: .leftAngle)
     var associatedTypes = [RawPrimaryAssociatedTypeSyntax]()
     do {
       var keepGoing: RawTokenSyntax? = nil

Tests/SwiftParserTest/Assertions.swift

@@ -560,6 +560,8 @@ fileprivate func assertRoundTrip<S: SyntaxProtocol>(
     // the mutated source and that it round-trips
     var mutatedParser = Parser(buf)
     let mutatedTree = parse(&mutatedParser)
+    // Run the diagnostic generator to make sure it doesn’t crash
+    _ = ParseDiagnosticsGenerator.diagnostics(for: mutatedTree)
     assertStringsEqualWithDiff(
       "\(mutatedTree)",
       mutatedSource,

Tests/SwiftParserTest/DeclarationTests.swift

@@ -2222,4 +2222,14 @@ final class DeclarationTests: XCTestCase {
         """
     )
   }
+
+  func testEmptyPrimaryAssociatedType() {
+    assertParse(
+      "protocol X<1️⃣> {}",
+      diagnostics: [
+        DiagnosticSpec(message: "expected name in primary associated type clause", fixIts: ["insert name"])
+      ],
+      fixedSource: "protocol X<<#identifier#>> {}"
+    )
+  }
 }

Tests/SwiftParserTest/StatementTests.swift

@@ -96,7 +96,7 @@ final class StatementTests: XCTestCase {
   }
 
   func testNestedIfs() {
-    let nest = 20
+    let nest = 10
     var source = "func nestThoseIfs() {\n"
     for index in (0...nest) {
       let indent = String(repeating: "    ", count: index + 1)