// first function that got substituted => allocate new out slice
				// and copy all functions
				new := make([]*Term, len(in))
				copy(new, out)
				out = new
				copied = true
			}
			out[i] = NewTerm(t.tilde, u)
		}
	}
	return
}

// replaceRecvType updates any function receivers that have type old to have
// type new. It does not modify the input slice; if modifications are required,

			// representable by each specific type in the type set of T.
			return Tp.is(func(t *term) bool {
				if t == nil {
					return false
				}
				// A term may be a tilde term but the underlying
				// type of an untyped value doesn't change so we
				// don't need to do anything special.
				newType, _, _ := check.implicitTypeAndValue(x, t.typ)
				return newType != nil

				// first function that got substituted => allocate new out slice
				// and copy all functions
				new := make([]*Term, len(in))
				copy(new, out)
				out = new
				copied = true
			}
			out[i] = NewTerm(t.tilde, u)
		}
	}
	return
}

// replaceRecvType updates any function receivers that have type old to have
// type new. It does not modify the input slice; if modifications are required,

	"∴":                       "\u2234",
	"Θ":                           "\u0398",
	"  ":                      "\u205f\u200a",
	" ":                       "\u2009",
	"∼":                           "\u223c",
	"≃":                      "\u2243",
	"≅":                  "\u2245",
	"≈":                      "\u2248",

}

func (h Hasher) hashTermSet(terms []*types.Term) uint32 {
	hash := 9157 + 2*uint32(len(terms))
	for _, term := range terms {
		// term order is not significant.
		termHash := h.Hash(term.Type())
		if term.Tilde() {
			termHash *= 9161
		}
		hash += 3 * termHash
	}
	return hash
}

// hashTypeParam returns a hash of the type parameter t, with a hash value
// depending on whether t is contained in h.sigTParams.

		"Tfr;":                             '\U0001D517',
		"Therefore;":                       '\U00002234',
		"Theta;":                           '\U00000398',
		"ThinSpace;":                       '\U00002009',
		"Tilde;":                           '\U0000223C',
		"TildeEqual;":                      '\U00002243',
		"TildeFullEqual;":                  '\U00002245',
		"TildeTilde;":                      '\U00002248',

		if s.ch == '=' {
			s.nextch()
			s.op, s.prec = Neq, precCmp
			s.tok = _Operator
			break
		}
		s.op, s.prec = Not, 0
		s.tok = _Operator

	case '~':
		s.nextch()
		s.op, s.prec = Tilde, 0
		s.tok = _Operator

	default:
		s.errorf("invalid character %#U", s.ch)
		s.nextch()
		goto redo
	}

	return

assignop:
	if s.ch == '=' {
		s.nextch()
		s.tok = _AssignOp

	{_Literal, "'\\U0000ff16'", 0, 0},
	{_Literal, "`foobar`", 0, 0},
	{_Literal, "`foo\tbar`", 0, 0},
	{_Literal, "`\r`", 0, 0},

	// operators
	{_Operator, "!", Not, 0},
	{_Operator, "~", Tilde, 0},

	{_Operator, "||", OrOr, precOrOr},

	{_Operator, "&&", AndAnd, precAndAnd},

	{_Operator, "==", Eql, precCmp},
	{_Operator, "!=", Neq, precCmp},
	{_Operator, "<", Lss, precCmp},

		{"!\"#$%&'()*+,-.／:;<=>?@[\\]^_`{|}~", true},
		{"␀␁␂␃␄␅␆␇␈␉␊␋␌␍␎␏␐␑␒␓␔␕␖␗␘␙␚␛␜␝␞␟␡", true},
		{"trailing VT␋/trailing VT␋", true},
		{"␋leading VT/␋leading VT", true},
		{"~leading tilde", true},
		{"\rleading CR", true},
		{"\nleading LF", true},
		{"\tleading HT", true},
		{"trailing CR\r", true},
		{"trailing LF\n", true},
		{"trailing HT\t", true},
		// cases for which test should fail.

        entities.put("Scaron", "\u0160");
        entities.put("scaron", "\u0161");
        entities.put("Yuml", "\u0178");
        entities.put("circ", "\u02c6");
        entities.put("tilde", "\u02dc");
        entities.put("ensp", "\u2002");
        entities.put("emsp", "\u2003");
        entities.put("thinsp", "\u2009");
        entities.put("zwnj", "\u200c");
        entities.put("zwj", "\u200d");