diff --git a/doc/NEWS.Rd b/doc/NEWS.Rd
index 67c59fee7d6..8b2a0e8eb02 100644
--- a/doc/NEWS.Rd
+++ b/doc/NEWS.Rd
@@ -207,6 +207,12 @@
       argument descriptions when they spanned multiple lines,
       including those generated by \code{prompt()}.
       These cases are now noted by \command{R CMD check}.
+
+      \item Communication between parent and child processes in
+      \code{multicore} part of \code{parallel} could fail on platforms
+      that do not support arbitrarily large payload in system functions
+      \code{read()}/\code{write()} on pipes (seen on macOS). The payload
+      is now split into 1Gb chunks to avoid that problem. \PR{18571}
     }
   }
 }
diff --git a/src/include/Rinlinedfuns.h b/src/include/Rinlinedfuns.h
index 03ab50c1db7..9f36975a7a4 100644
--- a/src/include/Rinlinedfuns.h
+++ b/src/include/Rinlinedfuns.h
@@ -1,7 +1,7 @@
 /*
  *  R : A Computer Language for Statistical Data Analysis
+ *  Copyright (C) 1999--2023  The R Core Team.
  *  Copyright (C) 1995, 1996  Robert Gentleman and Ross Ihaka
- *  Copyright (C) 1999-2017  The R Core Team.
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -108,7 +108,7 @@ INLINE_FUN void CHKVEC(SEXP x) {
     case WEAKREFSXP:
 	break;
     default:
-	error("cannot get data pointer of '%s' objects", type2char(TYPEOF(x)));
+	error("cannot get data pointer of '%s' objects", R_typeToChar(x));
     }
 }
 #else
diff --git a/src/include/Rinternals.h b/src/include/Rinternals.h
index 17affccb12b..231783cb177 100644
--- a/src/include/Rinternals.h
+++ b/src/include/Rinternals.h
@@ -129,7 +129,8 @@ typedef unsigned int SEXPTYPE;
 #define EXTPTRSXP   22    /* external pointer */
 #define WEAKREFSXP  23    /* weak reference */
 #define RAWSXP      24    /* raw bytes */
-#define S4SXP       25    /* S4, non-vector */
+#define OBJSXP      25    /* object, non-vector  */
+#define S4SXP       25    /* same as OBJSXP, retained for back compatability */
 
 /* used for detecting PROTECT issues in memory.c */
 #define NEWSXP      30    /* fresh node created in new page */
@@ -561,6 +562,10 @@ SEXP Rf_topenv(SEXP, SEXP);
 const char * Rf_translateChar(SEXP);
 const char * Rf_translateCharUTF8(SEXP);
 const char * Rf_type2char(SEXPTYPE);
+const char * R_typeToChar(SEXP);
+#ifdef USE_TYPE2CHAR_2
+const char * R_typeToChar2(SEXP, SEXPTYPE);
+#endif
 SEXP Rf_type2rstr(SEXPTYPE);
 SEXP Rf_type2str(SEXPTYPE);
 SEXP Rf_type2str_nowarn(SEXPTYPE);
diff --git a/src/library/methods/src/methods_list_dispatch.c b/src/library/methods/src/methods_list_dispatch.c
index cb4e48a334d..6dad2451366 100644
--- a/src/library/methods/src/methods_list_dispatch.c
+++ b/src/library/methods/src/methods_list_dispatch.c
@@ -127,7 +127,7 @@ static SEXP R_conditionMessage(SEXP cond)
     /* Type check return value so callers can safely extract a C string */
     if (TYPEOF(out) != STRSXP)
 	error(_("unexpected type '%s' for condition message"),
-	      type2char(TYPEOF(out)));
+	      R_typeToChar(out));
     if (length(out) != 1)
 	error(_("condition message must be length 1"));
 
diff --git a/src/library/stats/src/complete_cases.c b/src/library/stats/src/complete_cases.c
index 4fd75fadd93..239ec1a1506 100644
--- a/src/library/stats/src/complete_cases.c
+++ b/src/library/stats/src/complete_cases.c
@@ -62,7 +62,7 @@ SEXP compcases(SEXP args)
 			goto bad;
 		}
 		else
-		    error(R_MSG_type, type2char(TYPEOF(CAR(t))));
+		    error(R_MSG_type, R_typeToChar(CAR(t)));
 	}
 	/* FIXME : Need to be careful with the use of isVector() */
 	/* since this includes lists and expressions. */
@@ -113,7 +113,7 @@ SEXP compcases(SEXP args)
 		goto bad;
 	}
 	else
-	    error(R_MSG_type, type2char(TYPEOF(CAR(s))));
+	    error(R_MSG_type, R_typeToChar(CAR(s)));
     }
 
     if (len < 0)
@@ -151,7 +151,7 @@ SEXP compcases(SEXP args)
 			break;
 		    default:
 			UNPROTECT(1);
-			error(R_MSG_type, type2char(TYPEOF(u)));
+			error(R_MSG_type, R_typeToChar(u));
 		    }
 		}
 	    }
@@ -183,7 +183,7 @@ SEXP compcases(SEXP args)
 			break;
 		    default:
 			UNPROTECT(1);
-			error(R_MSG_type, type2char(TYPEOF(u)));
+			error(R_MSG_type, R_typeToChar(u));
 		    }
 		}
 	    }
@@ -211,7 +211,7 @@ SEXP compcases(SEXP args)
 		    break;
 		default:
 		    UNPROTECT(1);
-		    error(R_MSG_type, type2char(TYPEOF(u)));
+		    error(R_MSG_type, R_typeToChar(u));
 		}
 	    }
 	}
diff --git a/src/library/stats/src/deriv.c b/src/library/stats/src/deriv.c
index 4291fecbb4d..3aa42ede85b 100644
--- a/src/library/stats/src/deriv.c
+++ b/src/library/stats/src/deriv.c
@@ -786,7 +786,7 @@ SEXP doD(SEXP args)
     if (isExpression(CAR(args))) expr = VECTOR_ELT(CAR(args), 0);
     else expr = CAR(args);
     if (!(isLanguage(expr) || isSymbol(expr) || isNumeric(expr) || isComplex(expr)))
-        error(_("expression must not be type '%s'"), type2char(TYPEOF(expr)));
+        error(_("expression must not be type '%s'"), R_typeToChar(expr));
     SEXP var = CADR(args);
     if (!isString(var) || length(var) < 1)
 	error(_("variable must be a character string"));
diff --git a/src/library/stats/src/model.c b/src/library/stats/src/model.c
index 40ad9da388e..558fb8de6be 100644
--- a/src/library/stats/src/model.c
+++ b/src/library/stats/src/model.c
@@ -154,7 +154,7 @@ SEXP modelframe(SEXP call, SEXP op, SEXP args, SEXP rho)
 		break;
 	    default:
 		error(_("invalid type (%s) for variable '%s'"),
-		      type2char(TYPEOF(ans)),
+		      R_typeToChar(ans),
 		      translateChar(STRING_ELT(names, i)));
 	    }
 	    if (nrows(ans) != nr)
@@ -667,7 +667,7 @@ SEXP modelmatrix(SEXP call, SEXP op, SEXP args, SEXP rho)
 			}
 		    } else
 			error(_("variables of type '%s' are not allowed in model matrices"),
-			      type2char(TYPEOF(var_i)));
+			      R_typeToChar(var_i));
 		    indx /= ll;
 		}
 	    }
diff --git a/src/library/utils/R/str.R b/src/library/utils/R/str.R
index 0b5a67b8e18..2c8725c35e4 100644
--- a/src/library/utils/R/str.R
+++ b/src/library/utils/R/str.R
@@ -1,7 +1,7 @@
 #  File src/library/utils/R/str.R
 #  Part of the R package, https://www.R-project.org
 #
-#  Copyright (C) 1995-2021 The R Core Team
+#  Copyright (C) 1995-2023 The R Core Team
 #
 #  This program is free software; you can redistribute it and/or modify
 #  it under the terms of the GNU General Public License as published by
@@ -474,7 +474,7 @@ str.default <-
 			       )
 	    }
 	} else if(typeof(object) %in%
-		  c("externalptr", "weakref", "environment", "bytecode")) {
+		  c("externalptr", "weakref", "environment", "bytecode", "object")) {
 	    ## Careful here, we don't want to change pointer objects
 	    if(has.class)
                 cat(pClass(cl))
diff --git a/src/main/RNG.c b/src/main/RNG.c
index d685768d782..817ba3ac686 100644
--- a/src/main/RNG.c
+++ b/src/main/RNG.c
@@ -354,7 +354,7 @@ static Rboolean GetRNGkind(SEXP seeds)
 	if (seeds == R_MissingArg) /* How can this happen? */
 	    error(_("'.Random.seed' is a missing argument with no default"));
 	warning(_("'.Random.seed' is not an integer vector but of type '%s', so ignored"),
-		type2char(TYPEOF(seeds)));
+		R_typeToChar(seeds));
 	goto invalid;
     }
     is = INTEGER(seeds);
diff --git a/src/main/altclasses.c b/src/main/altclasses.c
index 9187dbc8541..96aa7a6c14d 100644
--- a/src/main/altclasses.c
+++ b/src/main/altclasses.c
@@ -1125,7 +1125,7 @@ static Rboolean mmap_Inspect(SEXP x, int pre, int deep, int pvec,
     Rboolean ptrOK = MMAP_PTROK(x);
     Rboolean wrtOK = MMAP_WRTOK(x);
     Rboolean serOK = MMAP_SEROK(x);
-    Rprintf(" mmaped %s", type2char(TYPEOF(x)));
+    Rprintf(" mmaped %s", R_typeToChar(x));
     Rprintf(" [ptr=%d,wrt=%d,ser=%d]\n", ptrOK, wrtOK, serOK);
     return TRUE;
 }
diff --git a/src/main/apply.c b/src/main/apply.c
index 43dbe6e3b51..432523ac3bb 100644
--- a/src/main/apply.c
+++ b/src/main/apply.c
@@ -126,7 +126,7 @@ attribute_hidden SEXP do_vapply(SEXP call, SEXP op, SEXP args, SEXP rho)
 	commonType != INTSXP  && commonType != LGLSXP &&
 	commonType != RAWSXP  && commonType != STRSXP &&
 	commonType != VECSXP)
-	error(_("type '%s' is not supported"), type2char(commonType));
+	error(_("type '%s' is not supported"), R_typeToChar(value));
     dim_v = getAttrib(value, R_DimSymbol);
     array_value = (TYPEOF(dim_v) == INTSXP && LENGTH(dim_v) >= 1);
     PROTECT(ans = allocVector(commonType, n*commonLen));
@@ -187,7 +187,7 @@ attribute_hidden SEXP do_vapply(SEXP call, SEXP op, SEXP args, SEXP rho)
 		}
 		if (!okay)
 		    error(_("values must be type '%s',\n but FUN(X[[%d]]) result is type '%s'"),
-			  type2char(commonType), i+1, type2char(valType));
+			  R_typeToChar(value), i+1, R_typeToChar(val));
 		REPROTECT(val = coerceVector(val, commonType), indx);
 	    }
 	    /* Take row names from the first result only */
diff --git a/src/main/array.c b/src/main/array.c
index 0a4b8197890..6e566d82bb1 100644
--- a/src/main/array.c
+++ b/src/main/array.c
@@ -84,7 +84,7 @@ attribute_hidden SEXP do_matrix(SEXP call, SEXP op, SEXP args, SEXP rho)
 	    break;
 	default:
 	    error(_("'data' must be of a vector type, was '%s'"),
-		type2char(TYPEOF(vals)));
+		R_typeToChar(vals));
     }
     lendat = XLENGTH(vals);
     snr = CAR(args); args = CDR(args);
@@ -2071,7 +2071,7 @@ attribute_hidden SEXP do_array(SEXP call, SEXP op, SEXP args, SEXP rho)
 	    break;
 	default:
 	    error(_("'data' must be of a vector type, was '%s'"),
-		type2char(TYPEOF(vals)));
+		R_typeToChar(vals));
     }
     lendat = XLENGTH(vals);
     dims = CADR(args);
diff --git a/src/main/attrib.c b/src/main/attrib.c
index 312390c0c48..f4cb057d526 100644
--- a/src/main/attrib.c
+++ b/src/main/attrib.c
@@ -75,7 +75,7 @@ static SEXP row_names_gets(SEXP vec, SEXP val)
 	}
     } else if(!isString(val))
 	error(_("row names must be 'character' or 'integer', not '%s'"),
-	      type2char(TYPEOF(val)));
+	      R_typeToChar(val));
     PROTECT(vec);
     PROTECT(val);
     ans =  installAttrib(vec, R_RowNamesSymbol, val);
@@ -135,7 +135,7 @@ attribute_hidden SEXP getAttrib0(SEXP vec, SEXP name)
 		}
 		else
 		    error(_("getAttrib: invalid type (%s) for TAG"),
-			  type2char(TYPEOF(TAG(vec))));
+			  R_typeToChar(TAG(vec)));
 	    }
 	    UNPROTECT(1);
 	    if (any) {
@@ -401,7 +401,7 @@ static void checkNames(SEXP x, SEXP s)
     if (isVector(x) || isList(x) || isLanguage(x)) {
 	if (!isVector(s) && !isList(s))
 	    error(_("invalid type (%s) for 'names': must be vector or NULL"),
-		  type2char(TYPEOF(s)));
+		  R_typeToChar(s));
 	if (xlength(x) != xlength(s))
 	    error(_("'names' attribute [%d] must be the same length as the vector [%d]"), length(s), length(x));
     }
@@ -1011,7 +1011,7 @@ SEXP namesgets(SEXP vec, SEXP val)
 	installAttrib(vec, R_NamesSymbol, val);
     else
 	error(_("invalid type (%s) to set 'names' attribute"),
-	      type2char(TYPEOF(vec)));
+	      R_typeToChar(vec));
     UNPROTECT(2);
     return vec;
 }
@@ -1131,7 +1131,7 @@ SEXP dimnamesgets(SEXP vec, SEXP val)
 	if (_this != R_NilValue) {
 	    if (!isVector(_this))
 		error(_("invalid type (%s) for 'dimnames' (must be a vector)"),
-		      type2char(TYPEOF(_this)));
+		      R_typeToChar(_this));
 	    if (INTEGER(dims)[i] != LENGTH(_this) && LENGTH(_this) != 0)
 		error(_("length of 'dimnames' [%d] not equal to array extent"),
 		      i+1);
@@ -1169,7 +1169,7 @@ attribute_hidden SEXP do_dimnames(SEXP call, SEXP op, SEXP args, SEXP env)
 }
 
 SEXP R_dim(SEXP call, SEXP op, SEXP args, SEXP env)
-{ 
+{
     SEXP ans;
     /* DispatchOrEval internal generic: dim */
     if (DispatchOrEval(call, op, "dim", args, env, &ans, 0, /* argsevald: */ 1))
@@ -1597,7 +1597,7 @@ attribute_hidden SEXP do_attrgets(SEXP call, SEXP op, SEXP args, SEXP env)
 	}
 	else {
 	    error(_("invalid type '%s' for slot name"),
-		  type2char(TYPEOF(nlist)));
+		  R_typeToChar(nlist));
 	    return R_NilValue; /*-Wall*/
 	}
 
diff --git a/src/main/bind.c b/src/main/bind.c
index e0881cecc15..cd275689a19 100644
--- a/src/main/bind.c
+++ b/src/main/bind.c
@@ -293,7 +293,7 @@ LogicalAnswer(SEXP x, struct BindData *data, SEXP call)
 	break;
     default:
 	errorcall(call, _("type '%s' is unimplemented in '%s'"),
-		  type2char(TYPEOF(x)), "LogicalAnswer");
+		  R_typeToChar(x), "LogicalAnswer");
     }
 }
 
@@ -329,7 +329,7 @@ IntegerAnswer(SEXP x, struct BindData *data, SEXP call)
 	break;
     default:
 	errorcall(call, _("type '%s' is unimplemented in '%s'"),
-		  type2char(TYPEOF(x)), "IntegerAnswer");
+		  R_typeToChar(x), "IntegerAnswer");
     }
 }
 
@@ -378,7 +378,7 @@ RealAnswer(SEXP x, struct BindData *data, SEXP call)
 	break;
     default:
 	errorcall(call, _("type '%s' is unimplemented in '%s'"),
-		  type2char(TYPEOF(x)), "RealAnswer");
+		  R_typeToChar(x), "RealAnswer");
     }
 }
 
@@ -451,7 +451,7 @@ ComplexAnswer(SEXP x, struct BindData *data, SEXP call)
 
     default:
 	errorcall(call, _("type '%s' is unimplemented in '%s'"),
-		  type2char(TYPEOF(x)), "ComplexAnswer");
+		  R_typeToChar(x), "ComplexAnswer");
     }
 }
 
@@ -479,7 +479,7 @@ RawAnswer(SEXP x, struct BindData *data, SEXP call)
 	break;
     default:
 	errorcall(call, _("type '%s' is unimplemented in '%s'"),
-		  type2char(TYPEOF(x)), "RawAnswer");
+		  R_typeToChar(x), "RawAnswer");
     }
 }
 
@@ -1162,8 +1162,8 @@ attribute_hidden SEXP do_bind(SEXP call, SEXP op, SEXP args, SEXP env)
 	   to an expression is not ideal.
 	   FIXME?  had  cbind(y ~ x, 1) work using lists, before */
     default:
-	error(_("cannot create a matrix from type '%s'"),
-	      type2char(mode));
+	error(_("cannot create a matrix from type '%s'"), 
+	      type2char(mode)); /* mode can only be EXPRSXP here */
     }
 
     if (PRIMVAL(op) == 1)
@@ -1396,6 +1396,8 @@ static SEXP cbind(SEXP call, SEXP args, SEXPTYPE mode, SEXP rho,
 			});
 		    } else
 			/* not sure this can be reached, but to be safe: */
+                        /* `mode` is created in do_bind(), it can only be one of the following:
+                         NILSXP, LGLSXP, INTSXP, REALSXP, CPLXSXP, STRSXP, VECSXP, RAWSXP */
 			error(_("cannot create a matrix of type '%s'"),
 			      type2char(mode));
 		}
diff --git a/src/main/builtin.c b/src/main/builtin.c
index a2ba2a70cce..6ddbd9c159a 100644
--- a/src/main/builtin.c
+++ b/src/main/builtin.c
@@ -667,7 +667,7 @@ attribute_hidden SEXP do_cat(SEXP call, SEXP op, SEXP args, SEXP rho)
 #endif
 	    else
 		error(_("argument %d (type '%s') cannot be handled by 'cat'"),
-		      1+iobj, type2char(TYPEOF(s)));
+		      1+iobj, R_typeToChar(s));
 	    /* FIXME : cat(...) should handle ANYTHING */
 	    size_t w = strlen(p);
 	    cat_sepwidth(sepr, &sepw, ntot);
diff --git a/src/main/coerce.c b/src/main/coerce.c
index 8a528dc6bb6..a3ee8ce907a 100644
--- a/src/main/coerce.c
+++ b/src/main/coerce.c
@@ -413,7 +413,7 @@ static SEXP coerceToSymbol(SEXP v)
     int warn = 0;
     if (length(v) <= 0)
 	error(_("invalid data of mode '%s' (too short)"),
-	      type2char(TYPEOF(v)));
+	      R_typeToChar(v));
     PROTECT(v);
     switch(TYPEOF(v)) {
     case LGLSXP:
@@ -1014,7 +1014,7 @@ static SEXP coercePairList(SEXP v, SEXPTYPE type)
     }
     else
 	error(_("'%s' object cannot be coerced to type '%s'"),
-	      type2char(TYPEOF(v)), type2char(type));
+	      R_typeToChar(v), type2char(type));
 
     /* If any tags are non-null then we */
     /* need to add a names attribute. */
@@ -1269,7 +1269,7 @@ SEXP coerceVector(SEXP v, SEXPTYPE type)
 #define COERCE_ERROR_STRING "cannot coerce type '%s' to vector of type '%s'"
 
 #define COERCE_ERROR							\
-	error(_(COERCE_ERROR_STRING), type2char(TYPEOF(v)), type2char(type))
+	error(_(COERCE_ERROR_STRING), R_typeToChar(v), type2char(type))
 
 	switch (type) {
 	case SYMSXP:
@@ -1397,7 +1397,7 @@ static SEXP ascommon(SEXP call, SEXP u, SEXPTYPE type)
 	return v;
     }
     else errorcall(call, _(COERCE_ERROR_STRING),
-		   type2char(TYPEOF(u)), type2char(type));
+		   R_typeToChar(u), type2char(type));
     return u;/* -Wall */
 }
 
@@ -1955,6 +1955,9 @@ Rcomplex asComplex(SEXP x)
 attribute_hidden SEXP do_typeof(SEXP call, SEXP op, SEXP args, SEXP rho)
 {
     checkArity(op, args);
+  if(TYPEOF(CAR(args)) == OBJSXP && !IS_S4_OBJECT(CAR(args)))
+    return mkString("object");
+  else
     return type2rstr(TYPEOF(CAR(args)));
 }
 
@@ -2156,7 +2159,7 @@ attribute_hidden SEXP do_isvector(SEXP call, SEXP op, SEXP args, SEXP rho)
     }
     /* So this allows any type, including undocumented ones such as
        "closure", but not aliases such as "name" and "function". */
-    else if (streql(stype, type2char(TYPEOF(x)))) {
+    else if (streql(stype, R_typeToChar(x))) {
 	LOGICAL0(ans)[0] = 1;
     }
     else
@@ -2310,7 +2313,7 @@ attribute_hidden SEXP do_isna(SEXP call, SEXP op, SEXP args, SEXP rho)
     case NILSXP: break;
     default:
 	warningcall(call, _("%s() applied to non-(list or vector) of type '%s'"),
-		    "is.na", type2char(TYPEOF(x)));
+		    "is.na", R_typeToChar(x));
 	for (i = 0; i < n; i++)
 	    pa[i] = 0;
     }
@@ -2428,7 +2431,7 @@ static Rboolean anyNA(SEXP call, SEXP op, SEXP args, SEXP env)
 
     default:
 	error("anyNA() applied to non-(list or vector) of type '%s'",
-	      type2char(TYPEOF(x)));
+	      R_typeToChar(x));
     }
     return FALSE;
 } // anyNA()
@@ -2506,7 +2509,7 @@ attribute_hidden SEXP do_isnan(SEXP call, SEXP op, SEXP args, SEXP rho)
 	break;
     default:
 	errorcall(call, _("default method not implemented for type '%s'"),
-		  type2char(TYPEOF(x)));
+		  R_typeToChar(x));
     }
     copyDimAndNames(x, ans);
     UNPROTECT(2); /* args, ans*/
@@ -2567,7 +2570,7 @@ attribute_hidden SEXP do_isfinite(SEXP call, SEXP op, SEXP args, SEXP rho)
 	break;
     default:
 	errorcall(call, _("default method not implemented for type '%s'"),
-		  type2char(TYPEOF(x)));
+		  R_typeToChar(x));
     }
     if (dims != R_NilValue)
 	setAttrib(ans, R_DimSymbol, dims);
@@ -2643,7 +2646,7 @@ attribute_hidden SEXP do_isinfinite(SEXP call, SEXP op, SEXP args, SEXP rho)
 	break;
     default:
 	errorcall(call, _("default method not implemented for type '%s'"),
-		  type2char(TYPEOF(x)));
+		  R_typeToChar(x));
     }
     if (!isNull(dims))
 	setAttrib(ans, R_DimSymbol, dims);
@@ -3011,7 +3014,7 @@ static SEXP R_set_class(SEXP obj, SEXP value, SEXP call)
 	    }
 	    else if(valueType != TYPEOF(obj))
 		error(_("\"%s\" can only be set as the class if the object has this type; found \"%s\""),
-		      valueString, type2char(TYPEOF(obj)));
+		      valueString, R_typeToChar(obj));
 	    /* else, leave alone */
 	}
 	else if(!strcmp("numeric", valueString)) {
diff --git a/src/main/deparse.c b/src/main/deparse.c
index 67b1db699e2..b4dcbd0a7dc 100644
--- a/src/main/deparse.c
+++ b/src/main/deparse.c
@@ -1506,9 +1506,15 @@ static void deparse2buff(SEXP s, LocalParseData *d)
 	d->sourceable = FALSE;
 	print2buff("<weak reference>", d);
 	break;
-    case S4SXP: {
-	error("'S4SXP': should not happen - please report");
-      break;
+    case OBJSXP: {
+	/*
+	print2buff("object(", d);
+	if(attr >= STRUC_ATTR) attr2(s, d, (attr == STRUC_ATTR));
+	 print2buff(")", d);
+	*/
+	d->sourceable = FALSE;
+	print2buff("<object>", d);
+	break;
     }
     default:
 	d->sourceable = FALSE;
diff --git a/src/main/dotcode.c b/src/main/dotcode.c
index d6b6bf32ab3..d867f1e4a30 100644
--- a/src/main/dotcode.c
+++ b/src/main/dotcode.c
@@ -395,7 +395,7 @@ static SEXP naokfind(SEXP args, int * len, int *naok, DllReference *dll)
 		    dll->dll = (HINSTANCE) R_ExternalPtrAddr(VECTOR_ELT(s, 4));
 		} else
 		    error("incorrect type (%s) of PACKAGE argument\n",
-			  type2char(TYPEOF(CAR(s))));
+			  R_typeToChar(CAR(s)));
 	    }
 	} else {
 	    nargs++;
@@ -542,7 +542,7 @@ static SEXP check_retval(SEXP call, SEXP val)
 
     return val;
 }
-    
+
 attribute_hidden SEXP do_External(SEXP call, SEXP op, SEXP args, SEXP env)
 {
     DL_FUNC ofun = NULL;
@@ -2024,7 +2024,7 @@ attribute_hidden SEXP do_dotCode(SEXP call, SEXP op, SEXP args, SEXP env)
 	    break;
 	case VECSXP:
 	    if (Fort) error(_("invalid mode (%s) to pass to Fortran (arg %d)"),
-			    type2char(t), na + 1);
+			    R_typeToChar(s), na + 1);
 	    /* Used read-only, so this is safe */
 #ifdef USE_RINTERNALS
             if (!ALTREP(s))
@@ -2045,20 +2045,20 @@ attribute_hidden SEXP do_dotCode(SEXP call, SEXP op, SEXP args, SEXP env)
 	case SPECIALSXP:
 	case ENVSXP:
 	    if (Fort) error(_("invalid mode (%s) to pass to Fortran (arg %d)"),
-			    type2char(t), na + 1);
+			    R_typeToChar(s), na + 1);
 	    cargs[na] =  (void*) s;
 	    break;
 	case NILSXP:
 	    error(_("invalid mode (%s) to pass to C or Fortran (arg %d)"),
-		  type2char(t), na + 1);
+		  R_typeToChar(s), na + 1);
 	    cargs[na] =  (void*) s;
 	    break;
 	default:
 	    /* Includes pairlists from R 2.15.0 */
 	    if (Fort) error(_("invalid mode (%s) to pass to Fortran (arg %d)"),
-			    type2char(t), na + 1);
+			    R_typeToChar(s), na + 1);
 	    warning("passing an object of type '%s' to .C (arg %d) is deprecated",
-		    type2char(t), na + 1);
+		    R_typeToChar(s), na + 1);
 	    if (t == LISTSXP)
 		warning(_("pairlists are passed as SEXP as from R 2.15.0"));
 	    cargs[na] =  (void*) s;
diff --git a/src/main/errors.c b/src/main/errors.c
index 9d9bba5e19c..8a0ff380619 100644
--- a/src/main/errors.c
+++ b/src/main/errors.c
@@ -2339,7 +2339,7 @@ R_BadValueInRCode(SEXP value, SEXP call, SEXP rho, const char *rawmsg,
 	REprintf(" --- R stacktrace ---\n");
 	printwhere();
 	REprintf(" --- value of length: %d type: %s ---\n",
-		 length(value), type2char(TYPEOF(value)));
+		 length(value), R_typeToChar(value));
 	PrintValue(value);
 	REprintf(" --- function from context --- \n");
 	if (R_GlobalContext->callfun != NULL &&
@@ -2792,7 +2792,7 @@ attribute_hidden
 SEXP R_makeNotSubsettableError(SEXP x, SEXP call)
 {
     SEXP cond = R_makeErrorCondition(call, "notSubsettableError", NULL, 1,
-				     R_MSG_ob_nonsub, type2char(TYPEOF(x)));
+				     R_MSG_ob_nonsub, R_typeToChar(x));
     PROTECT(cond);
     R_setConditionField(cond, 2, "object", x);
     UNPROTECT(1);
diff --git a/src/main/eval.c b/src/main/eval.c
index 0f63a62a43d..a9c4399b956 100644
--- a/src/main/eval.c
+++ b/src/main/eval.c
@@ -970,7 +970,7 @@ SEXP eval(SEXP e, SEXP rho)
 	error("'rho' cannot be C NULL: detected in C-level eval");
     if (!isEnvironment(rho))
 	error("'rho' must be an environment not %s: detected in C-level eval",
-	      type2char(TYPEOF(rho)));
+	      R_typeToChar(rho));
 
     /* Save the current srcref context. */
 
@@ -2062,7 +2062,7 @@ SEXP applyClosure(SEXP call, SEXP op, SEXP arglist, SEXP rho, SEXP suppliedvars)
 		  "'rho' cannot be C NULL: detected in C-level applyClosure");
     if (!isEnvironment(rho))
 	errorcall(call, "'rho' must be an environment not %s: detected in C-level applyClosure",
-		  type2char(TYPEOF(rho)));
+		  R_typeToChar(rho));
 
     formals = FORMALS(op);
     savedrho = CLOENV(op);
@@ -3581,7 +3581,7 @@ attribute_hidden SEXP do_eval(SEXP call, SEXP op, SEXP args, SEXP rho)
     } else if ( !isEnvironment(encl) &&
 		!isEnvironment((encl = simple_as_environment(encl))) ) {
 	error(_("invalid '%s' argument of type '%s'"),
-	      "enclos", type2char(tEncl));
+	      "enclos", R_typeToChar(encl));
     }
     if(IS_S4_OBJECT(env) && (TYPEOF(env) == S4SXP))
 	env = R_getS4DataSlot(env, ANYSXP); /* usually an ENVSXP */
@@ -3612,12 +3612,12 @@ attribute_hidden SEXP do_eval(SEXP call, SEXP op, SEXP args, SEXP rho)
 	frame = asInteger(env);
 	if (frame == NA_INTEGER)
 	    error(_("invalid '%s' argument of type '%s'"),
-		  "envir", type2char(TYPEOF(env)));
+		  "envir", R_typeToChar(env));
 	PROTECT(env = R_sysframe(frame, R_GlobalContext));
 	break;
     default:
 	error(_("invalid '%s' argument of type '%s'"),
-	      "envir", type2char(TYPEOF(env)));
+	      "envir", R_typeToChar(env));
     }
 
     /* isLanguage include NILSXP, and that does not need to be
diff --git a/src/main/identical.c b/src/main/identical.c
index edc5d089425..52dbbc3b278 100644
--- a/src/main/identical.c
+++ b/src/main/identical.c
@@ -364,7 +364,7 @@ R_compute_identical(SEXP x, SEXP y, int flags)
     default:
 	/* these are all supposed to be types that represent constant
 	   entities, so no further testing required ?? */
-	printf("Unknown Type in identical(): %s (%x)\n", type2char(TYPEOF(x)), TYPEOF(x));
+	printf("Unknown Type in identical(): %s (%x)\n", R_typeToChar(x), TYPEOF(x));
 	return TRUE;
     }
 }
diff --git a/src/main/inspect.c b/src/main/inspect.c
index 59da140914d..07f71355a28 100644
--- a/src/main/inspect.c
+++ b/src/main/inspect.c
@@ -67,6 +67,8 @@ static void pp(int pre) {
 }
 
 static const char *typename(SEXP v) {
+    if(TYPEOF(v) == OBJSXP && IS_S4_OBJECT(v))
+	return "S4SXP";
     return sexptype2char(TYPEOF(v)); // -> memory.c
 }
 
diff --git a/src/main/logic.c b/src/main/logic.c
index 293439793f5..445066b2b93 100644
--- a/src/main/logic.c
+++ b/src/main/logic.c
@@ -482,7 +482,7 @@ attribute_hidden SEXP do_logic3(SEXP call, SEXP op, SEXP args, SEXP env)
 	    if(TYPEOF(t) != INTSXP)
 		warningcall(call,
 			    _("coercing argument of type '%s' to logical"),
-			    type2char(TYPEOF(t)));
+			    R_typeToChar(t));
 	    t = coerceVector(t, LGLSXP);
 	}
 	val = checkValues(PRIMVAL(op), narm, t, XLENGTH(t));
diff --git a/src/main/memory.c b/src/main/memory.c
index d6add5eed57..16a2f0b28fd 100644
--- a/src/main/memory.c
+++ b/src/main/memory.c
@@ -215,7 +215,7 @@ const char *sexptype2char(SEXPTYPE type) {
     case BCODESXP:	return "BCODESXP";
     case EXTPTRSXP:	return "EXTPTRSXP";
     case WEAKREFSXP:	return "WEAKREFSXP";
-    case S4SXP:		return "S4SXP";
+    case OBJSXP:	return "OBJSXP"; /* was S4SXP */
     case RAWSXP:	return "RAWSXP";
     case NEWSXP:	return "NEWSXP"; /* should never happen */
     case FREESXP:	return "FREESXP";
@@ -1039,7 +1039,7 @@ static void TryToReleasePages(void)
 
 	    maxrel = R_GenHeap[i].AllocCount;
 	    for (gen = 0; gen < NUM_OLD_GENERATIONS; gen++)
-		maxrel -= (int)((1.0 + R_MaxKeepFrac) * 
+		maxrel -= (int)((1.0 + R_MaxKeepFrac) *
 				R_GenHeap[i].OldCount[gen]);
 	    maxrel_pages = maxrel > 0 ? maxrel / page_count : 0;
 
@@ -3101,7 +3101,7 @@ attribute_hidden void R_check_thread(const char *s)
     }
 }
 # else
-/* This could be implemented for Windows using their threading API */ 
+/* This could be implemented for Windows using their threading API */
 attribute_hidden void R_check_thread(const char *s) {}
 # endif
 #endif
@@ -3817,7 +3817,7 @@ void (MARK_ASSIGNMENT_CALL)(SEXP x) { MARK_ASSIGNMENT_CALL(CHK(x)); }
 void (SET_ATTRIB)(SEXP x, SEXP v) {
     if(TYPEOF(v) != LISTSXP && TYPEOF(v) != NILSXP)
 	error("value of 'SET_ATTRIB' must be a pairlist or NULL, not a '%s'",
-	      type2char(TYPEOF(v)));
+	      R_typeToChar(v));
     FIX_REFCNT(x, ATTRIB(x), v);
     CHECK_OLD_TO_NEW(x, v);
     ATTRIB(x) = v;
@@ -3875,7 +3875,7 @@ static R_INLINE SEXP CHK2(SEXP x)
 {
     x = CHK(x);
     if(nvec[TYPEOF(x)])
-	error("LENGTH or similar applied to %s object", type2char(TYPEOF(x)));
+	error("LENGTH or similar applied to %s object", R_typeToChar(x));
     return x;
 }
 
@@ -3890,7 +3890,7 @@ void (SETLENGTH)(SEXP x, R_xlen_t v)
 	error("SETLENGTH() cannot be applied to an ALTVEC object.");
     if (! isVector(x))
 	error(_("SETLENGTH() can only be applied to a standard vector, "
-		"not a '%s'"), type2char(TYPEOF(x)));
+		"not a '%s'"), R_typeToChar(x));
     SET_STDVEC_LENGTH(CHK2(x), v);
 }
 
@@ -3908,14 +3908,14 @@ R_xlen_t Rf_XLENGTH(SEXP x) { return XLENGTH(x); }
 const char *(R_CHAR)(SEXP x) {
     if(TYPEOF(x) != CHARSXP) // Han-Tak proposes to prepend  'x && '
 	error("%s() can only be applied to a '%s', not a '%s'",
-	      "CHAR", "CHARSXP", type2char(TYPEOF(x)));
+	      "CHAR", "CHARSXP", R_typeToChar(x));
     return (const char *) CHAR(CHK(x));
 }
 
 SEXP (STRING_ELT)(SEXP x, R_xlen_t i) {
     if(TYPEOF(x) != STRSXP)
 	error("%s() can only be applied to a '%s', not a '%s'",
-	      "STRING_ELT", "character vector", type2char(TYPEOF(x)));
+	      "STRING_ELT", "character vector", R_typeToChar(x));
     if (ALTREP(x))
 	return CHK(ALTSTRING_ELT(CHK(x), i));
     else {
@@ -3930,7 +3930,7 @@ SEXP (VECTOR_ELT)(SEXP x, R_xlen_t i) {
        TYPEOF(x) != EXPRSXP &&
        TYPEOF(x) != WEAKREFSXP)
 	error("%s() can only be applied to a '%s', not a '%s'",
-	      "VECTOR_ELT", "list", type2char(TYPEOF(x)));
+	      "VECTOR_ELT", "list", R_typeToChar(x));
     if (ALTREP(x)) {
 	SEXP ans = CHK(ALTLIST_ELT(CHK(x), i));
 	/* the element is marked as not mutable since complex
@@ -3965,7 +3965,7 @@ void *(STDVEC_DATAPTR)(SEXP x)
 	error("cannot get STDVEC_DATAPTR from ALTREP object");
     if (! isVector(x) && TYPEOF(x) != WEAKREFSXP)
 	error("STDVEC_DATAPTR can only be applied to a vector, not a '%s'",
-	      type2char(TYPEOF(x)));
+	      R_typeToChar(x));
     CHKZLN(x);
     return STDVEC_DATAPTR(x);
 }
@@ -3973,7 +3973,7 @@ void *(STDVEC_DATAPTR)(SEXP x)
 int *(LOGICAL)(SEXP x) {
     if(TYPEOF(x) != LGLSXP)
 	error("%s() can only be applied to a '%s', not a '%s'",
-	      "LOGICAL",  "logical", type2char(TYPEOF(x)));
+	      "LOGICAL",  "logical", R_typeToChar(x));
     CHKZLN(x);
     return LOGICAL(x);
 }
@@ -3981,7 +3981,7 @@ int *(LOGICAL)(SEXP x) {
 const int *(LOGICAL_RO)(SEXP x) {
     if(TYPEOF(x) != LGLSXP)
 	error("%s() can only be applied to a '%s', not a '%s'",
-	      "LOGICAL",  "logical", type2char(TYPEOF(x)));
+	      "LOGICAL",  "logical", R_typeToChar(x));
     CHKZLN(x);
     return LOGICAL_RO(x);
 }
@@ -3990,7 +3990,7 @@ const int *(LOGICAL_RO)(SEXP x) {
 int *(INTEGER)(SEXP x) {
     if(TYPEOF(x) != INTSXP && TYPEOF(x) != LGLSXP)
 	error("%s() can only be applied to a '%s', not a '%s'",
-	      "INTEGER", "integer", type2char(TYPEOF(x)));
+	      "INTEGER", "integer", R_typeToChar(x));
     CHKZLN(x);
     return INTEGER(x);
 }
@@ -3998,7 +3998,7 @@ int *(INTEGER)(SEXP x) {
 const int *(INTEGER_RO)(SEXP x) {
     if(TYPEOF(x) != INTSXP && TYPEOF(x) != LGLSXP)
 	error("%s() can only be applied to a '%s', not a '%s'",
-	      "INTEGER", "integer", type2char(TYPEOF(x)));
+	      "INTEGER", "integer", R_typeToChar(x));
     CHKZLN(x);
     return INTEGER_RO(x);
 }
@@ -4006,7 +4006,7 @@ const int *(INTEGER_RO)(SEXP x) {
 Rbyte *(RAW)(SEXP x) {
     if(TYPEOF(x) != RAWSXP)
 	error("%s() can only be applied to a '%s', not a '%s'",
-	      "RAW", "raw", type2char(TYPEOF(x)));
+	      "RAW", "raw", R_typeToChar(x));
     CHKZLN(x);
     return RAW(x);
 }
@@ -4014,7 +4014,7 @@ Rbyte *(RAW)(SEXP x) {
 const Rbyte *(RAW_RO)(SEXP x) {
     if(TYPEOF(x) != RAWSXP)
 	error("%s() can only be applied to a '%s', not a '%s'",
-	      "RAW", "raw", type2char(TYPEOF(x)));
+	      "RAW", "raw", R_typeToChar(x));
     CHKZLN(x);
     return RAW(x);
 }
@@ -4022,7 +4022,7 @@ const Rbyte *(RAW_RO)(SEXP x) {
 double *(REAL)(SEXP x) {
     if(TYPEOF(x) != REALSXP)
 	error("%s() can only be applied to a '%s', not a '%s'",
-	      "REAL", "numeric", type2char(TYPEOF(x)));
+	      "REAL", "numeric", R_typeToChar(x));
     CHKZLN(x);
     return REAL(x);
 }
@@ -4030,7 +4030,7 @@ double *(REAL)(SEXP x) {
 const double *(REAL_RO)(SEXP x) {
     if(TYPEOF(x) != REALSXP)
 	error("%s() can only be applied to a '%s', not a '%s'",
-	      "REAL", "numeric", type2char(TYPEOF(x)));
+	      "REAL", "numeric", R_typeToChar(x));
     CHKZLN(x);
     return REAL_RO(x);
 }
@@ -4038,7 +4038,7 @@ const double *(REAL_RO)(SEXP x) {
 Rcomplex *(COMPLEX)(SEXP x) {
     if(TYPEOF(x) != CPLXSXP)
 	error("%s() can only be applied to a '%s', not a '%s'",
-	      "COMPLEX", "complex", type2char(TYPEOF(x)));
+	      "COMPLEX", "complex", R_typeToChar(x));
     CHKZLN(x);
     return COMPLEX(x);
 }
@@ -4046,7 +4046,7 @@ Rcomplex *(COMPLEX)(SEXP x) {
 const Rcomplex *(COMPLEX_RO)(SEXP x) {
     if(TYPEOF(x) != CPLXSXP)
 	error("%s() can only be applied to a '%s', not a '%s'",
-	      "COMPLEX", "complex", type2char(TYPEOF(x)));
+	      "COMPLEX", "complex", R_typeToChar(x));
     CHKZLN(x);
     return COMPLEX_RO(x);
 }
@@ -4054,7 +4054,7 @@ const Rcomplex *(COMPLEX_RO)(SEXP x) {
 SEXP *(STRING_PTR)(SEXP x) {
     if(TYPEOF(x) != STRSXP)
 	error("%s() can only be applied to a '%s', not a '%s'",
-	      "STRING_PTR", "character", type2char(TYPEOF(x)));
+	      "STRING_PTR", "character", R_typeToChar(x));
     CHKZLN(x);
     return STRING_PTR(x);
 }
@@ -4062,7 +4062,7 @@ SEXP *(STRING_PTR)(SEXP x) {
 const SEXP *(STRING_PTR_RO)(SEXP x) {
     if(TYPEOF(x) != STRSXP)
 	error("%s() can only be applied to a '%s', not a '%s'",
-	      "STRING_PTR_RO", "character", type2char(TYPEOF(x)));
+	      "STRING_PTR_RO", "character", R_typeToChar(x));
     CHKZLN(x);
     return STRING_PTR_RO(x);
 }
@@ -4075,10 +4075,10 @@ NORET SEXP * (VECTOR_PTR)(SEXP x)
 void (SET_STRING_ELT)(SEXP x, R_xlen_t i, SEXP v) {
     if(TYPEOF(CHK(x)) != STRSXP)
 	error("%s() can only be applied to a '%s', not a '%s'",
-	      "SET_STRING_ELT", "character vector", type2char(TYPEOF(x)));
+	      "SET_STRING_ELT", "character vector", R_typeToChar(x));
     if(TYPEOF(CHK(v)) != CHARSXP)
        error("Value of SET_STRING_ELT() must be a 'CHARSXP' not a '%s'",
-	     type2char(TYPEOF(v)));
+	     R_typeToChar(v));
     if (i < 0 || i >= XLENGTH(x))
 	error(_("attempt to set index %lld/%lld in SET_STRING_ELT"),
 	      (long long)i, (long long)XLENGTH(x));
@@ -4098,7 +4098,7 @@ SEXP (SET_VECTOR_ELT)(SEXP x, R_xlen_t i, SEXP v) {
        TYPEOF(x) != EXPRSXP &&
        TYPEOF(x) != WEAKREFSXP) {
 	error("%s() can only be applied to a '%s', not a '%s'",
-	      "SET_VECTOR_ELT", "list", type2char(TYPEOF(x)));
+	      "SET_VECTOR_ELT", "list", R_typeToChar(x));
     }
     if (i < 0 || i >= XLENGTH(x))
 	error(_("attempt to set index %lld/%lld in SET_VECTOR_ELT"),
@@ -4132,7 +4132,7 @@ static R_INLINE SEXP CHKCONS(SEXP e)
 	return CHK(e);
     default:
 	error("CAR/CDR/TAG or similar applied to %s object",
-	      type2char(TYPEOF(e)));
+	      R_typeToChar(e));
     }
 }
 #else
@@ -4438,7 +4438,7 @@ void (SET_PRSEEN)(SEXP x, int v) { SET_PRSEEN(CHK(x), v); }
 void (SET_PRVALUE)(SEXP x, SEXP v)
 {
     if (TYPEOF(x) != PROMSXP)
-	error("expecting a 'PROMSXP', not a '%s'", type2char(TYPEOF(x)));
+	error("expecting a 'PROMSXP', not a '%s'", R_typeToChar(x));
     FIX_REFCNT(x, PRVALUE(x), v);
     CHECK_OLD_TO_NEW(x, v);
     PRVALUE(x) = v;
@@ -4471,7 +4471,7 @@ SEXP (SET_CXTAIL)(SEXP x, SEXP v) {
 #ifdef USE_TYPE_CHECKING
     if(TYPEOF(v) != CHARSXP && TYPEOF(v) != NILSXP)
 	error("value of 'SET_CXTAIL' must be a char or NULL, not a '%s'",
-	      type2char(TYPEOF(v)));
+	      R_typeToChar(v));
 #endif
     /*CHECK_OLD_TO_NEW(x, v); *//* not needed since not properly traced */
     ATTRIB(x) = v;
diff --git a/src/main/objects.c b/src/main/objects.c
index a4369697009..4ddc5067dc5 100644
--- a/src/main/objects.c
+++ b/src/main/objects.c
@@ -1421,7 +1421,7 @@ SEXP do_set_prim_method(SEXP op, const char *code_string, SEXP fundef,
     else if(fundef && !isNull(fundef) && !prim_generics[offset]) {
 	if(TYPEOF(fundef) != CLOSXP)
 	    error(_("the formal definition of a primitive generic must be a function object (got type '%s')"),
-		  type2char(TYPEOF(fundef)));
+		  R_typeToChar(fundef));
 	R_PreserveObject(fundef);
 	prim_generics[offset] = fundef;
     }
diff --git a/src/main/print.c b/src/main/print.c
index 79a7f63c0b4..e20596a6bd0 100644
--- a/src/main/print.c
+++ b/src/main/print.c
@@ -1,6 +1,6 @@
 /*
  *  R : A Computer Language for Statistical Data Analysis
- *  Copyright (C) 2000-2022	The R Core Team.
+ *  Copyright (C) 2000-2023	The R Core Team.
  *  Copyright (C) 1995-1998	Robert Gentleman and Ross Ihaka.
  *
  *  This program is free software; you can redistribute it and/or modify
@@ -852,7 +852,7 @@ attribute_hidden void PrintValueRec(SEXP s, R_PrintData *data)
 		Rprintf("<S4 object without a class>\n");
 	    else
 		Rprintf("<Object of type '%s' with S4 bit but without a class>\n",
-			type2char(TYPEOF(s)));
+			R_typeToChar(s));
 	} else {
 	    SEXP pkg = getAttrib(s, R_PackageSymbol);
 	    if(isNull(pkg)) {
@@ -967,11 +967,16 @@ attribute_hidden void PrintValueRec(SEXP s, R_PrintData *data)
     case WEAKREFSXP:
 	Rprintf("<weak reference>\n");
 	break;
-    case S4SXP:
+    case OBJSXP:
+      if(IS_S4_OBJECT(s)) {
 	/*  we got here because no show method, usually no class.
 	    Print the "slots" as attributes, since we don't know the class.
 	*/
 	Rprintf("<S4 Type Object>\n");
+      } else {
+	  /* OBJSXP type, S4 obj bit not set*/
+	  Rprintf("<object>\n");
+      }
 	break;
     default:
 	UNIMPLEMENTED_TYPE("PrintValueRec", s);
diff --git a/src/main/radixsort.c b/src/main/radixsort.c
index 0d3d1636408..c56e737766d 100644
--- a/src/main/radixsort.c
+++ b/src/main/radixsort.c
@@ -1648,7 +1648,7 @@ attribute_hidden SEXP do_radixsort(SEXP call, SEXP op, SEXP args, SEXP rho)
 	break;
     default :
         Error("First arg is type '%s', not yet supported",
-              type2char(TYPEOF(x)));
+              R_typeToChar(x));
     }
     if (tmp) {
 	// -1 or 1. NEW: or -2 in case of nalast == 0 and all NAs
@@ -1755,7 +1755,7 @@ attribute_hidden SEXP do_radixsort(SEXP call, SEXP op, SEXP args, SEXP rho)
 	    break;
 	default:
 	    Error("Arg %d is type '%s', not yet supported",
-		  col, type2char(TYPEOF(x)));
+		  col, R_typeToChar(x));
 	}
 	int i = 0;
 	for (int grp = 0; grp < ngrp; grp++) {
diff --git a/src/main/seq.c b/src/main/seq.c
index 37d1d06f65f..a98db408c69 100644
--- a/src/main/seq.c
+++ b/src/main/seq.c
@@ -352,11 +352,11 @@ attribute_hidden SEXP do_rep_int(SEXP call, SEXP op, SEXP args, SEXP rho)
 
     if (!isVector(ncopy))
 	error(_("invalid type (%s) for '%s' (must be a vector)"),
-	      type2char(TYPEOF(ncopy)), "times");
+	      R_typeToChar(ncopy), "times");
 
     if (!isVector(s) && s != R_NilValue)
 	error(_("attempt to replicate an object of type '%s'"),
-	      type2char(TYPEOF(s)));
+	      R_typeToChar(s));
 
     nc = xlength(ncopy); // might be 0
     if (nc == xlength(s))
@@ -706,7 +706,7 @@ attribute_hidden SEXP do_rep(SEXP call, SEXP op, SEXP args, SEXP rho)
     }
     if (!isVector(x))
 	errorcall(call, "attempt to replicate an object of type '%s'",
-		  type2char(TYPEOF(x)));
+		  R_typeToChar(x));
 
     /* So now we know x is a vector of positive length.  We need to
        replicate it, and its names if it has them. */
diff --git a/src/main/subassign.c b/src/main/subassign.c
index 449d8d88012..13b7dbef669 100644
--- a/src/main/subassign.c
+++ b/src/main/subassign.c
@@ -475,7 +475,7 @@ static int SubassignTypeFix(SEXP *x, SEXP *y, R_xlen_t stretch, int level,
 
     default:
 	error(_("incompatible types (from %s to %s) in subassignment type fix"),
-	      type2char(which%100), type2char(which/100));
+	      R_typeToChar(*x), R_typeToChar(*y));
     }
 
     if (stretch) {
@@ -1122,7 +1122,7 @@ static SEXP MatrixAssign(SEXP call, SEXP rho, SEXP x, SEXP s, SEXP y)
 
     default:
 	error(_("incompatible types (from %s to %s) in matrix subset assignment"),
-		  type2char(which%100), type2char(which/100));
+		  R_typeToChar(x), R_typeToChar(y));
     }
     UNPROTECT(2);
     return x;
@@ -1356,7 +1356,7 @@ static SEXP ArrayAssign(SEXP call, SEXP rho, SEXP x, SEXP s, SEXP y)
 
     default:
 	error(_("incompatible types (from %s to %s) in array subset assignment"),
-	      type2char(which%100), type2char(which/100));
+	      R_typeToChar(x), R_typeToChar(y));
     }
 
     UNPROTECT(3);
@@ -2019,7 +2019,7 @@ do_subassign2_dflt(SEXP call, SEXP op, SEXP args, SEXP rho)
 
 	default:
 	    error(_("incompatible types (from %s to %s) in [[ assignment"),
-		  type2char(which%100), type2char(which/100));
+		  R_typeToChar(x), R_typeToChar(y));
 	}
 	/* If we stretched, we may have a new name. */
 	/* In this case we must create a names attribute */
diff --git a/src/main/subscript.c b/src/main/subscript.c
index 751cf0632a4..a1701018174 100644
--- a/src/main/subscript.c
+++ b/src/main/subscript.c
@@ -198,7 +198,7 @@ OneIndex(SEXP x, SEXP s, R_xlen_t nx, int partial, SEXP *newname,
 	vmaxset(vmax);
 	break;
     default:
-	ECALL3(call, _("invalid subscript type '%s'"), type2char(TYPEOF(s)));
+	ECALL3(call, _("invalid subscript type '%s'"), R_typeToChar(s));
     }
     return indx;
 }
@@ -332,7 +332,7 @@ get1index(SEXP s, SEXP names, R_xlen_t len, int pok, int pos, SEXP call)
 	    }
 	break;
     default:
-	ECALL3(call, _("invalid subscript type '%s'"), type2char(TYPEOF(s)));
+	ECALL3(call, _("invalid subscript type '%s'"), R_typeToChar(s));
     }
     return indx;
 }
@@ -1021,7 +1021,7 @@ int_arraySubscript(int dim, SEXP s, SEXP dims, SEXP x, SEXP call)
 	if (s == R_MissingArg)
 	    return nullSubscript(nd);
     default:
-	ECALL3(call, _("invalid subscript type '%s'"), type2char(TYPEOF(s)));
+	ECALL3(call, _("invalid subscript type '%s'"), R_typeToChar(s));
     }
     return R_NilValue;
 }
@@ -1105,7 +1105,7 @@ makeSubscript(SEXP x, SEXP s, R_xlen_t *stretch, SEXP call)
 	    break;
 	}
     default:
-	ECALL3(call, _("invalid subscript type '%s'"), type2char(TYPEOF(s)));
+	ECALL3(call, _("invalid subscript type '%s'"), R_typeToChar(s));
     }
     return ans;
 }
diff --git a/src/main/subset.c b/src/main/subset.c
index 37862e02b18..51729e000c5 100644
--- a/src/main/subset.c
+++ b/src/main/subset.c
@@ -95,7 +95,7 @@ static R_INLINE SEXP VECTOR_ELT_FIX_NAMED(SEXP y, R_xlen_t i) {
 
 NORET static void errorcallNotSubsettable(SEXP x, SEXP call)
 {
-    SEXP cond = R_makeNotSubsettableError(x, call);
+    SEXP cond = R_makeNotSubsettableError(x, call);  // object of type '..' is not subsettable
     PROTECT(cond);
     R_signalErrorCondition(cond, call);
     UNPROTECT(1); /* cond; not reached */
@@ -734,7 +734,6 @@ attribute_hidden SEXP do_subset_dflt(SEXP call, SEXP op, SEXP args, SEXP rho)
     if (cdrArgs != R_NilValue && cddrArgs == R_NilValue &&
 	TAG(cdrArgs) == R_NilValue) {
 	/* one index, not named */
-	SEXP x = CAR(args);
 	if (ATTRIB(x) == R_NilValue) {
 	    SEXP s = CAR(cdrArgs);
 	    R_xlen_t i = scalarIndex(s);
@@ -767,7 +766,6 @@ attribute_hidden SEXP do_subset_dflt(SEXP call, SEXP op, SEXP args, SEXP rho)
     else if (cddrArgs != R_NilValue && CDR(cddrArgs) == R_NilValue &&
 	     TAG(cdrArgs) == R_NilValue && TAG(cddrArgs) == R_NilValue) {
 	/* two indices, not named */
-	SEXP x = CAR(args);
 	SEXP attr = ATTRIB(x);
 	if (TAG(attr) == R_DimSymbol && CDR(attr) == R_NilValue) {
 	    /* only attribute of x is 'dim' */
@@ -967,11 +965,8 @@ attribute_hidden SEXP do_subset2_dflt(SEXP call, SEXP op, SEXP args, SEXP rho)
     /* Is partial matching ok?  When the exact arg is NA, a warning is
        issued if partial matching occurs.
      */
-    int exact = ExtractExactArg(args), pok;
-    if (exact == -1)
-	pok = exact;
-    else
-	pok = !exact;
+    int exact = ExtractExactArg(args),
+	pok = (exact == -1) ? exact : !exact;
 
     x = CAR(args);
 
@@ -998,10 +993,12 @@ attribute_hidden SEXP do_subset2_dflt(SEXP call, SEXP op, SEXP args, SEXP rho)
 	errorcall(call, _("incorrect number of subscripts"));
 
     /* code to allow classes to extend environment */
-    if(TYPEOF(x) == S4SXP) {
+    if(TYPEOF(x) == OBJSXP) {
+	SEXP xs = x;
 	x = R_getS4DataSlot(x, ANYSXP);
 	if(x == R_NilValue)
-	  errorcall(call, _("this S4 class is not subsettable"));
+	    errorcall(call, _("this %s class is not subsettable"),
+		      IS_S4_OBJECT(xs) ? "S4" : "object");
     }
     PROTECT(x);
 
@@ -1231,7 +1228,7 @@ fixSubset3Args(SEXP call, SEXP args, SEXP env, SEXP* syminp)
     }
     else {
 	errorcall(call,_("invalid subscript type '%s'"),
-		  type2char(TYPEOF(nlist)));
+		  R_typeToChar(nlist));
 	return R_NilValue; /*-Wall*/
     }
 
diff --git a/src/main/summary.c b/src/main/summary.c
index 168efba3764..25e8503e7b9 100644
--- a/src/main/summary.c
+++ b/src/main/summary.c
@@ -552,7 +552,7 @@ attribute_hidden SEXP do_summary(SEXP call, SEXP op, SEXP args, SEXP env)
 	case REALSXP: return real_mean(x);
 	case CPLXSXP: return complex_mean(x);
 	default:
-	    error(R_MSG_type, type2char(TYPEOF(x)));
+	    error(R_MSG_type, R_typeToChar(x));
 	    return R_NilValue; // -Wall on clang 4.2
 	}
     }
@@ -625,7 +625,7 @@ attribute_hidden SEXP do_summary(SEXP call, SEXP op, SEXP args, SEXP env)
     int itmp = 0, icum = 0, warn = 0 /* dummy */;
     Rboolean use_isum = TRUE; // indicating if isum() should used; otherwise irsum()
     isum_INT iLtmp = (isum_INT)0, iLcum = iLtmp; // for isum() only
-    SEXPTYPE ans_type;/* only INTEGER, REAL, COMPLEX or STRSXP here */
+    SEXPTYPE ans_type; /* only INTEGER, REAL, COMPLEX or STRSXP here */
 
     int iop = PRIMVAL(op);
     switch(iop) {
@@ -990,7 +990,7 @@ attribute_hidden SEXP do_summary(SEXP call, SEXP op, SEXP args, SEXP env)
     return ans;
 
 invalid_type:
-    errorcall(call, R_MSG_type, type2char(TYPEOF(a)));
+    errorcall(call, R_MSG_type, R_typeToChar(a));
     return R_NilValue;
 }/* do_summary */
 
diff --git a/src/main/sysutils.c b/src/main/sysutils.c
index 23df85fba4d..1300564c930 100644
--- a/src/main/sysutils.c
+++ b/src/main/sysutils.c
@@ -883,7 +883,7 @@ attribute_hidden SEXP do_iconv(SEXP call, SEXP op, SEXP args, SEXP env)
     SEXP __x__ = (x);            \
     if(TYPEOF(__x__) != CHARSXP) \
 	error(_("'%s' must be called on a CHARSXP, but got '%s'"), \
-	      __func__, type2char(TYPEOF(__x__)));                 \
+	      __func__, R_typeToChar(__x__));			   \
 } while(0);
 
 cetype_t getCharCE(SEXP x)
diff --git a/src/main/util.c b/src/main/util.c
index 52f90342ea3..718f5f7f758 100644
--- a/src/main/util.c
+++ b/src/main/util.c
@@ -219,6 +219,7 @@ TypeTable[] = {
     { "weakref",	WEAKREFSXP },
     { "raw",		RAWSXP },
     { "S4",		S4SXP },
+    { "object",		OBJSXP }, /* == S4SXP */
     /* aliases : */
     { "numeric",	REALSXP	   },
     { "name",		SYMSXP	   },
@@ -234,6 +235,9 @@ SEXPTYPE str2type(const char *s)
 	if (!strcmp(s, TypeTable[i].str))
 	    return (SEXPTYPE) TypeTable[i].type;
     }
+    if (!strcmp(s, "object"))
+	return (SEXPTYPE) OBJSXP;
+
     /* SEXPTYPE is an unsigned int, so the compiler warns us w/o the cast. */
     return (SEXPTYPE) -1;
 }
@@ -328,6 +332,21 @@ const char *type2char(SEXPTYPE t) /* returns a char* */
     return buf;
 }
 
+#ifdef USE_TYPE2CHAR_2
+const char *R_typeToChar2(SEXP x, SEXPTYPE t) {
+    return (t != OBJSXP)
+	? type2char(t)
+	: (IS_S4_OBJECT(x) ? "S4" : "object");
+}
+#endif
+
+const char *R_typeToChar(SEXP x) { // = type2char() but distinguishing {S4, object}
+    if(TYPEOF(x) == OBJSXP)
+	return IS_S4_OBJECT(x) ? "S4" : "object";
+    // else
+    return type2char(TYPEOF(x));
+}
+
 #ifdef UNUSED
 NORET SEXP type2symbol(SEXPTYPE t)
 {
diff --git a/src/scripts/BATCH b/src/scripts/BATCH
index ece68924c3a..2e27da336f9 100644
--- a/src/scripts/BATCH
+++ b/src/scripts/BATCH
@@ -1,7 +1,7 @@
 #
 # ${R_HOME}/bin/BATCH
 
-revision='$Rev$'
+revision='$Rev: 83927 $'
 version=`set - ${revision}; echo ${2}`
 version="R batch front end: ${R_VERSION} (r${version})
 
diff --git a/src/scripts/COMPILE b/src/scripts/COMPILE
index eb121f6e8ae..ab8296778cc 100644
--- a/src/scripts/COMPILE
+++ b/src/scripts/COMPILE
@@ -3,7 +3,7 @@
 
 # @configure_input@
 
-revision='$Rev$'
+revision='$Rev: 75653 $'
 version=`set - ${revision}; echo ${2}`
 version="R compilation front end: ${R_VERSION} (r${version})
 
diff --git a/src/scripts/LINK b/src/scripts/LINK
index c3ceda2acb7..ad84733403c 100644
--- a/src/scripts/LINK
+++ b/src/scripts/LINK
@@ -1,7 +1,7 @@
 ##
 ## ${R_HOME}/bin/LINK
 
-revision='$Rev$'
+revision='$Rev: 75653 $'
 version=`set - ${revision}; echo ${2}`
 version="R linker front end: ${R_VERSION} (r${version})
 
diff --git a/src/scripts/config b/src/scripts/config
index 6d2c4e36d4d..b8d8f55ed46 100644
--- a/src/scripts/config
+++ b/src/scripts/config
@@ -20,7 +20,7 @@
 ## A copy of the GNU General Public License is available at
 ## https://www.R-project.org/Licenses/
 
-revision='$Revision$'
+revision='$Revision: 83600 $'
 version=`set - ${revision}; echo ${2}`
 version="R configuration information retrieval script: ${R_VERSION} (r${version})
 
diff --git a/src/scripts/javareconf.in b/src/scripts/javareconf.in
index ffd199e7cd6..6ffb704604c 100644
--- a/src/scripts/javareconf.in
+++ b/src/scripts/javareconf.in
@@ -9,7 +9,7 @@ fi
 DYLIB_EXT=`${R_HOME}/bin/R CMD config DYLIB_EXT`
 tools_classpath=${R_SHARE_DIR}/java
 
-revision='$Rev$'
+revision='$Rev: 84173 $'
 version=`set - ${revision}; echo ${2}`
 version="R Java configurator: ${R_VERSION} (r${version})
 
diff --git a/src/scripts/rtags.in b/src/scripts/rtags.in
index 8f30b44faec..2c3a0c42299 100644
--- a/src/scripts/rtags.in
+++ b/src/scripts/rtags.in
@@ -3,7 +3,7 @@
 ## Examples:
 ##  R CMD rtags -o TAGS /path/to/Rsrc/
 
-revision='$Rev$'
+revision='$Rev: 83932 $'
 version=`set - ${revision}; echo ${2}`
 version="rtags/etags front-end: ${R_VERSION} (r${version})