Add interface build checks for tree types and generated base listeners

runtime/Go/antlr/tree.go

@@ -56,6 +56,8 @@ type ParseTreeVisitor interface {
 
 type BaseParseTreeVisitor struct{}
 
+var _ ParseTreeVisitor = &BaseParseTreeVisitor{}
+
 func (v *BaseParseTreeVisitor) Visit(tree ParseTree) interface{}            { return nil }
 func (v *BaseParseTreeVisitor) VisitChildren(node RuleNode) interface{}     { return nil }
 func (v *BaseParseTreeVisitor) VisitTerminal(node TerminalNode) interface{} { return nil }
@@ -91,6 +93,8 @@ type ParseTreeListener interface {
 
 type BaseParseTreeListener struct{}
 
+var _ ParseTreeListener = &BaseParseTreeListener{}
+
 func (l *BaseParseTreeListener) VisitTerminal(node TerminalNode)      {}
 func (l *BaseParseTreeListener) VisitErrorNode(node ErrorNode)        {}
 func (l *BaseParseTreeListener) EnterEveryRule(ctx ParserRuleContext) {}
@@ -102,6 +106,8 @@ type TerminalNodeImpl struct {
 	symbol Token
 }
 
+var _ TerminalNode = &TerminalNodeImpl{}
+
 func NewTerminalNodeImpl(symbol Token) *TerminalNodeImpl {
 	tn := new(TerminalNodeImpl)
 
@@ -181,6 +187,8 @@ type ErrorNodeImpl struct {
 	*TerminalNodeImpl
 }
 
+var _ ErrorNode = &ErrorNodeImpl{}
+
 func NewErrorNodeImpl(token Token) *ErrorNodeImpl {
 	en := new(ErrorNodeImpl)
 	en.TerminalNodeImpl = NewTerminalNodeImpl(token)

tool/resources/org/antlr/v4/tool/templates/codegen/Go/Go.stg

@@ -75,6 +75,8 @@ import "github.com/pboyer/antlr4/runtime/Go/antlr"
 // Base<file.grammarName>Listener is a complete listener for a parse tree produced by <file.parserName>.
 type Base<file.grammarName>Listener struct{}
 
+var _ <file.grammarName>Listener = &Base<file.grammarName>Listener{}
+
 // VisitTerminal is called when a terminal node is visited.
 func (s *Base<file.grammarName>Listener) VisitTerminal(node antlr.TerminalNode) {}