Validate expected nodes

config.yml

@@ -811,8 +811,6 @@ nodes:
           - GlobalVariableReadNode
           - BackReferenceReadNode
           - NumberedReferenceReadNode
-          - on error: SymbolNode # alias $a b
-          - on error: MissingNode # alias $a 42
         comment: |
           Represents the old name of the global variable that can be used before aliasing.
 
@@ -853,8 +851,6 @@ nodes:
         kind:
           - SymbolNode
           - InterpolatedSymbolNode
-          - on error: GlobalVariableReadNode # alias a $b
-          - on error: MissingNode # alias a 42
         comment: |
           Represents the old name of the method that will be aliased.
 
@@ -1867,7 +1863,6 @@ nodes:
         kind:
           - ConstantReadNode
           - ConstantPathNode
-          - on error: CallNode # class 0.X end
       - name: inheritance_operator_loc
         type: location?
         comment: |
@@ -2422,6 +2417,13 @@ nodes:
           ^^^^^^
             bar
           end
+  - name: ErrorRecoveryNode
+    fields:
+      - name: child
+        type: node?
+        kind: Node
+    comment: |
+      Represents a node that is either missing or unexpected and results in a syntax error.
   - name: FalseNode
     comment: |
       Represents the use of the literal `false` keyword.
@@ -2464,9 +2466,7 @@ nodes:
                                ^^^^^^
       - name: right
         type: node
-        kind:
-          - SplatNode
-          - on error: MissingNode
+        kind: SplatNode
         comment: |
           Represents the second wildcard node in the pattern.
 
@@ -2549,9 +2549,6 @@ nodes:
           - CallTargetNode
           - IndexTargetNode
           - MultiTargetNode
-          - on error: BackReferenceReadNode # for $& in a end
-          - on error: NumberedReferenceReadNode # for $1 in a end
-          - on error: MissingNode # for in 1..10; end
         comment: |
           The index expression for `for` loops.
 
@@ -3305,10 +3302,6 @@ nodes:
           - EmbeddedStatementsNode
           - EmbeddedVariableNode
           - InterpolatedStringNode # `"a" "#{b}"`
-          - on error: XStringNode # `<<`FOO` "bar"
-          - on error: InterpolatedXStringNode
-          - on error: SymbolNode
-          - on error: InterpolatedSymbolNode
       - name: closing_loc
         type: location?
     newline: parts
@@ -3686,9 +3679,6 @@ nodes:
 
           /(?<foo>bar)/ =~ baz
           ^^^^^^^^^^^^^^^^^^^^
-  - name: MissingNode
-    comment: |
-      Represents a node that is missing from the source and results in a syntax error.
   - name: ModuleNode
     fields:
       - name: locals
@@ -3700,7 +3690,6 @@ nodes:
         kind:
           - ConstantReadNode
           - ConstantPathNode
-          - on error: MissingNode # module Parent module end
       - name: body
         type: node?
         kind:
@@ -3730,8 +3719,6 @@ nodes:
           - IndexTargetNode
           - MultiTargetNode
           - RequiredParameterNode # def m((a,b)); end
-          - on error: BackReferenceReadNode # a, (b, $&) = z
-          - on error: NumberedReferenceReadNode # a, (b, $1) = z
         comment: |
           Represents the targets expressions before a splat node.
 
@@ -3775,8 +3762,6 @@ nodes:
           - IndexTargetNode
           - MultiTargetNode
           - RequiredParameterNode # def m((*,b)); end
-          - on error: BackReferenceReadNode # a, (*, $&) = z
-          - on error: NumberedReferenceReadNode # a, (*, $1) = z
         comment: |
           Represents the targets expressions after a splat node.
 
@@ -3820,8 +3805,6 @@ nodes:
           - CallTargetNode
           - IndexTargetNode
           - MultiTargetNode
-          - on error: BackReferenceReadNode # $&, = z
-          - on error: NumberedReferenceReadNode # $1, = z
         comment: |
           Represents the targets expressions before a splat node.
 
@@ -3864,8 +3847,6 @@ nodes:
           - CallTargetNode
           - IndexTargetNode
           - MultiTargetNode
-          - on error: BackReferenceReadNode # *, $& = z
-          - on error: NumberedReferenceReadNode # *, $1 = z
         comment: |
           Represents the targets expressions after a splat node.
 
@@ -4051,11 +4032,6 @@ nodes:
         kind:
           - RequiredParameterNode
           - MultiTargetNode
-          # On parsing error of `f(**kwargs, ...)` or `f(**nil, ...)`, the keyword_rest value is moved here:
-          - on error: KeywordRestParameterNode
-          - on error: NoKeywordsParameterNode
-          # On parsing error of `f(..., ...)`, the first forwarding parameter is moved here:
-          - on error: ForwardingParameterNode
       - name: keywords
         type: node[]
         kind:
@@ -4140,7 +4116,6 @@ nodes:
           - BackReferenceReadNode # foo in ^$&
           - NumberedReferenceReadNode # foo in ^$1
           - ItLocalVariableReadNode # proc { 1 in ^it }
-          - on error: MissingNode # foo in ^Bar
         comment: |
           The variable used in the pinned expression
 
@@ -4223,7 +4198,7 @@ nodes:
 
               1...foo
                   ^^^
-          If neither right-hand or left-hand side was included, this will be a MissingNode.
+          If neither right-hand or left-hand side was included, this will be an ErrorRecoveryNode.
       - name: operator_loc
         type: location
         comment: |
@@ -4338,9 +4313,6 @@ nodes:
           - ConstantPathTargetNode
           - CallTargetNode
           - IndexTargetNode
-          - on error: BackReferenceReadNode # => begin; rescue => $&; end
-          - on error: NumberedReferenceReadNode # => begin; rescue => $1; end
-          - on error: MissingNode # begin; rescue =>; end
       - name: then_keyword_loc
         type: location?
       - name: statements

lib/prism/node_ext.rb

@@ -208,7 +208,7 @@ def child
       if name
         ConstantReadNode.new(source, -1, name_loc, 0, name)
       else
-        MissingNode.new(source, -1, location, 0)
+        ErrorRecoveryNode.new(source, -1, location, 0, nil)
       end
     end
   end
@@ -249,7 +249,7 @@ def child
       if name
         ConstantReadNode.new(source, -1, name_loc, 0, name)
       else
-        MissingNode.new(source, -1, location, 0)
+        ErrorRecoveryNode.new(source, -1, location, 0, nil)
       end
     end
   end

rakelib/lint.rake

@@ -29,7 +29,7 @@ task :lint do
     exit(1)
   end
 
-  if (uncommented = nodes.select { |node| !%w[MissingNode ProgramNode].include?(node.fetch("name")) && !node.fetch("comment").match?(/^\s{4}/) }).any?
+  if (uncommented = nodes.select { |node| !%w[ErrorRecoveryNode ProgramNode].include?(node.fetch("name")) && !node.fetch("comment").match?(/^\s{4}/) }).any?
     names = uncommented.map { |node| node.fetch("name") }
     warn("Expected all nodes to have an example, missing comments for #{names.join(", ")}")
     exit(1)

rust/ruby-prism/build.rs

@@ -47,27 +47,12 @@ enum NodeFieldType {
     Double,
 }
 
-#[derive(Debug, Deserialize)]
-#[allow(dead_code)]
-struct OnErrorType {
-    #[serde(rename = "on error")]
-    kind: String,
-}
-
-#[derive(Debug, Deserialize)]
-#[serde(untagged)]
-#[allow(dead_code)]
-enum UnionKind {
-    OnSuccess(String),
-    OnError(OnErrorType),
-}
-
 #[derive(Debug, Deserialize)]
 #[serde(untagged)]
 #[allow(dead_code)]
 enum NodeFieldKind {
     Concrete(String),
-    Union(Vec<UnionKind>),
+    Union(Vec<String>),
 }
 
 #[derive(Debug, Deserialize)]

sig/prism/node_ext.rbs

@@ -60,18 +60,18 @@ module Prism
     class DynamicPartsInConstantPathError < StandardError
     end
 
-    class MissingNodesInConstantPathError < StandardError
+    class ErrorRecoveryNodesInConstantPathError < StandardError
     end
 
     def full_name_parts: () -> Array[Symbol]
     def full_name: () -> String
-    def child: () -> (ConstantReadNode | MissingNode)
+    def child: () -> (ConstantReadNode | ErrorRecoveryNode)
   end
 
   class ConstantPathTargetNode < Node
     def full_name_parts: () -> Array[Symbol]
     def full_name: () -> String
-    def child: () -> (ConstantReadNode | MissingNode)
+    def child: () -> (ConstantReadNode | ErrorRecoveryNode)
   end
 
   class ConstantTargetNode < Node