The check for 'sym1 == sym2' is redundant here because it has already
been done a few lines above:

    if (sym1 != sym2)
            return NULL;

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Currently, comparisons to 'm' or 'n' result in incorrect output.

[Test Code]

    config MODULES
            def_bool y
            modules

    config A
            def_tristate m

    config B
            def_bool A > n

CONFIG_B is unset, while CONFIG_B=y is expected.

The reason for the issue is because Kconfig compares the tristate values
as strings.

Currently, the .type fields in the constant symbol definitions,
symbol_{yes,mod,no} are unspecified, i.e., S_UNKNOWN.

When expr_calc_value() evaluates 'A > n', it checks the types of 'A' and
'n' to determine how to compare them.

The left-hand side, 'A', is a tristate symbol with a value of 'm', which
corresponds to a numeric value of 1. (Internally, 'y', 'm', and 'n' are
represented as 2, 1, and 0, respectively.)

The right-hand side, 'n', has an unknown type, so it is treated as the
string "n" during the comparison.

expr_calc_value() compares two values numerically only when both can
have numeric values. Otherwise, they are compared as strings.

    symbol    numeric value    ASCII code
    -------------------------------------
      y           2             0x79
      m           1             0x6d
      n           0             0x6e

'm' is greater than 'n' if compared numerically (since 1 is greater
than 0), but smaller than 'n' if compared as strings (since the ASCII
code 0x6d is smaller than 0x6e).

Specifying .type=S_TRISTATE for symbol_{yes,mod,no} fixes the above
test code.

Doing so, however, would cause a regression to the following test code.

[Test Code 2]

    config MODULES
            def_bool n
            modules

    config A
            def_tristate n

    config B
            def_bool A = m

You would get CONFIG_B=y, while CONFIG_B should not be set.

The reason is because sym_get_string_value() turns 'm' into 'n' when the
module feature is disabled. Consequently, expr_calc_value() evaluates
'A = n' instead of 'A = m'. This oddity has been hidden because the type
of 'm' was previously S_UNKNOWN instead of S_TRISTATE.

sym_get_string_value() should not tweak the string because the tristate
value has already been correctly calculated. There is no reason to
return the string "n" where its tristate value is mod.

Fixes: 31847b67bec0 ("kconfig: allow use of relations other than (in)equality")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

This has not been used since commit e911503085ae ("Kconfig: Remove
bad inference rules expr_eliminate_dups2()").

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Choices and their members are associated via the P_CHOICE property.

Currently, prop_get_symbol(sym_get_choice_prop()) is used to obtain
the choice of the given choice member.

Replace it with sym_get_choice_menu(), which retrieves the choice
without relying on P_CHOICE.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

A_NORMAL is zero, so the attribute is set to the default A_NORMAL
without explicit assignment.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Just trivial cleanups.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Previously, optional bool choices met the following conditions
simultaneously:

 - sym_is_choice(sym)
 - sym_is_changeable(sym)
 - type == S_BOOLEAN

It no longer occurs since 6a1215888e23 ("kconfig: remove 'optional'
property support"). Remove the dead code.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

This code previously displayed child symbols of the selected choice
member.

Since commit 7e3465f63a0a ("kconfig: do not reparent the menu inside
a choice block"), choice members never have child symbols, therefore
this is dead code.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Currently, bool choices have a checkbox, but tristate choices do not.
It is opposite.

Bool choices should not have a checkbox, as they are fixed to 'y' since
commit 6a1215888e23 ("kconfig: remove 'optional' property support").
Tristate choices, however, should have a checkbox to allow users to
toggle the value.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Choices and their members are associated via the P_CHOICE property.

Currently, sym_get_choice_prop() and expr_list_for_each_sym() are
used to iterate on choice members.

Replace them with menu_for_each_sub_entry(), which achieves the same
without relying on P_CHOICE.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>