[Typed throws] Add thrown type to effect specifiers

Author: DougGregor

CodeGeneration/Sources/SyntaxSupport/CommonNodes.swift

@@ -79,6 +79,27 @@ public let COMMON_NODES: [Node] = [
     ]
   ),
 
+  Node(
+    kind: .thrownType,
+    base: .syntax,
+    nameForDiagnostics: "thrown type",
+    children: [
+      Child(
+        name: "leftParen",
+        kind: .token(choices: [.token(.leftParen)])
+      ),
+      Child(
+        name: "type",
+        kind: .node(kind: .type),
+        nameForDiagnostics: "type"
+      ),
+      Child(
+        name: "rightParen",
+        kind: .token(choices: [.token(.rightParen)])
+      ),
+    ]
+  ),
+
   Node(
     kind: .accessorEffectSpecifiers,
     base: .syntax,
@@ -99,6 +120,11 @@ public let COMMON_NODES: [Node] = [
         documentation: "The `throws` keyword.",
         isOptional: true
       ),
+      Child(
+        name: "thrownType",
+        kind: .node(kind: .thrownType),
+        isOptional: true
+      ),
     ]
   ),
 
@@ -122,6 +148,11 @@ public let COMMON_NODES: [Node] = [
         documentation: "The `throws` or `rethrows` keyword.",
         isOptional: true
       ),
+      Child(
+        name: "thrownType",
+        kind: .node(kind: .thrownType),
+        isOptional: true
+      ),
     ]
   ),
 
@@ -324,6 +355,11 @@ public let COMMON_NODES: [Node] = [
         kind: .token(choices: [.keyword(.throws)]),
         isOptional: true
       ),
+      Child(
+        name: "thrownType",
+        kind: .node(kind: .thrownType),
+        isOptional: true
+      ),
     ]
   ),
 

CodeGeneration/Sources/SyntaxSupport/SyntaxNodeKind.swift

@@ -268,6 +268,7 @@ public enum SyntaxNodeKind: String, CaseIterable {
   case switchExpr
   case ternaryExpr
   case thenStmt
+  case thrownType
   case throwStmt
   case tryExpr
   case tupleExpr

CodeGeneration/Sources/SyntaxSupport/Traits.swift

@@ -56,7 +56,13 @@ public let TRAITS: [Trait] = [
       Child(name: "asyncSpecifier", kind: .token(choices: [.keyword(.async), .keyword(.reasync)]), isOptional: true),
       Child(name: "unexpectedBetweenAsyncSpecifierAndThrowsSpecifier", kind: .node(kind: .unexpectedNodes), isOptional: true),
       Child(name: "throwsSpecifier", kind: .token(choices: [.keyword(.throws), .keyword(.rethrows)]), isOptional: true),
-      Child(name: "unexpectedAfterThrowsSpecifier", kind: .node(kind: .unexpectedNodes), isOptional: true),
+      Child(name: "unexpectedBetweenThrowsSpecifierAndThrownType", kind: .node(kind: .unexpectedNodes), isOptional: true),
+      Child(
+        name: "thrownType",
+        kind: .node(kind: .thrownType),
+        isOptional: true
+      ),
+      Child(name: "unexpectedAfterThrownType", kind: .node(kind: .unexpectedNodes), isOptional: true),
     ]
   ),
   Trait(