diff --git a/src/go/parser/parser.go b/src/go/parser/parser.go
index 18278ba4b7..e82c0bd122 100644
--- a/src/go/parser/parser.go
+++ b/src/go/parser/parser.go
@@ -7,6 +7,13 @@
 // output is an abstract syntax tree (AST) representing the Go source. The
 // parser is invoked through one of the Parse* functions.
 //
+// The parser accepts a larger language than is syntactically permitted by
+// the Go spec, for simplicity, and for improved robustness in the presence
+// of syntax errors. For instance, in method declarations, the receiver is
+// treated like an ordinary parameter list and thus may contain multiple
+// entries where the spec permits exactly one. Consequently, the corresponding
+// field in the AST (ast.FuncDecl.Recv) field is not restricted to one entry.
+//
 package parser
 
 import (