bpo-39969: Remove ast.Param node class as is no longer used (GH-19020)

Author: isidentical

Doc/whatsnew/3.9.rst

@@ -664,8 +664,9 @@ Removed
   defining ``COUNT_ALLOCS`` macro.
   (Contributed by Victor Stinner in :issue:`39489`.)
 
-* The ``ast.Suite`` node class has been removed due to no longer being needed.
-  (Contributed by Batuhan Taskaya in :issue:`39639`.)
+* The ``ast.Suite`` and ``ast.Param`` node classes has been removed due to no
+  longer being needed.
+  (Contributed by Batuhan Taskaya in :issue:`39639` and :issue:`39969`.)
 
 
 Porting to Python 3.9

Include/Python-ast.h

@@ -0,0 +1,2 @@
+Remove ``ast.Param`` node class because it's no longer used. Patch by
+Batuhan Taskaya.

Misc/NEWS.d/next/Library/2020-03-15-17-56-48.bpo-39969.6snm0c.rst

@@ -90,7 +90,7 @@ module Python
           -- col_offset is the byte offset in the utf8 string the parser uses
           attributes (int lineno, int col_offset, int? end_lineno, int? end_col_offset)
 
-    expr_context = Load | Store | Del | AugLoad | AugStore | Param
+    expr_context = Load | Store | Del | AugLoad | AugStore
 
     boolop = And | Or
 

Parser/Python.asdl

@@ -75,8 +75,6 @@ expr_context_name(expr_context_ty ctx)
         return "AugLoad";
     case AugStore:
         return "AugStore";
-    case Param:
-        return "Param";
     default:
         Py_UNREACHABLE();
     }

Python/Python-ast.c

@@ -3579,10 +3579,10 @@ compiler_nameop(struct compiler *c, identifier name, expr_context_ty ctx)
         case AugStore:
             break;
         case Del: op = DELETE_DEREF; break;
-        case Param:
         default:
-            PyErr_SetString(PyExc_SystemError,
-                            "param invalid for deref variable");
+            PyErr_Format(PyExc_SystemError,
+                         "expr_context kind %d should not be possible",
+                         ctx);
             return 0;
         }
         break;
@@ -3596,10 +3596,10 @@ compiler_nameop(struct compiler *c, identifier name, expr_context_ty ctx)
         case AugLoad:
         case AugStore:
             break;
-        case Param:
         default:
-            PyErr_SetString(PyExc_SystemError,
-                            "param invalid for local variable");
+            PyErr_Format(PyExc_SystemError,
+                         "expr_context kind %d should not be possible",
+                         ctx);
             return 0;
         }
         ADDOP_N(c, op, mangled, varnames);
@@ -3614,10 +3614,10 @@ compiler_nameop(struct compiler *c, identifier name, expr_context_ty ctx)
         case AugLoad:
         case AugStore:
             break;
-        case Param:
         default:
-            PyErr_SetString(PyExc_SystemError,
-                            "param invalid for global variable");
+            PyErr_Format(PyExc_SystemError,
+                         "expr_context kind %d should not be possible",
+                         ctx);
             return 0;
         }
         break;
@@ -3631,10 +3631,10 @@ compiler_nameop(struct compiler *c, identifier name, expr_context_ty ctx)
         case AugLoad:
         case AugStore:
             break;
-        case Param:
         default:
-            PyErr_SetString(PyExc_SystemError,
-                            "param invalid for name variable");
+            PyErr_Format(PyExc_SystemError,
+                         "expr_context kind %d should not be possible",
+                         ctx);
             return 0;
         }
         break;
@@ -5058,10 +5058,10 @@ compiler_visit_expr1(struct compiler *c, expr_ty e)
         case Del:
             ADDOP_NAME(c, DELETE_ATTR, e->v.Attribute.attr, names);
             break;
-        case Param:
         default:
-            PyErr_SetString(PyExc_SystemError,
-                            "param invalid in attribute expression");
+            PyErr_Format(PyExc_SystemError,
+                         "expr_context kind %d should not be possible",
+                         e->v.Attribute.ctx);
             return 0;
         }
         break;
@@ -5359,9 +5359,10 @@ compiler_subscript(struct compiler *c, expr_ty e)
         case AugStore:/* fall through to Store */
         case Store:   op = STORE_SUBSCR; break;
         case Del:     op = DELETE_SUBSCR; break;
-        case Param:
-            PyErr_SetString(PyExc_SystemError,
-                "param invalid in subscript expression");
+        default:
+            PyErr_Format(PyExc_SystemError,
+                         "expr_context kind %d should not be possible",
+                         ctx);
             return 0;
     }
     if (ctx == AugStore) {