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bpo-43892: Make match patterns explicit in the AST (GH-25585)

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Co-authored-by: Brandt Bucher <brandtbucher@gmail.com>
This commit is contained in:
Nick Coghlan 2021-04-29 15:58:44 +10:00 • committed by GitHub
parent e52ab42ced
commit 1e7b858575
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20 changed files with 3460 additions and 1377 deletions
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1160
Python/Python-ast.c generated
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238
Python/ast.c
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@ -7,6 +7,7 @@
#include "pycore_pystate.h" // _PyThreadState_GET()
#include <assert.h>
#include <stdbool.h>
struct validator {
int recursion_depth; /* current recursion depth */
@ -18,6 +19,7 @@ static int validate_exprs(struct validator *, asdl_expr_seq*, expr_context_ty, i
static int _validate_nonempty_seq(asdl_seq *, const char *, const char *);
static int validate_stmt(struct validator *, stmt_ty);
static int validate_expr(struct validator *, expr_ty, expr_context_ty);
static int validate_pattern(struct validator *, pattern_ty);
static int
validate_name(PyObject *name)
@ -88,9 +90,9 @@ expr_context_name(expr_context_ty ctx)
return "Store";
case Del:
return "Del";
default:
Py_UNREACHABLE();
// No default case so compiler emits warning for unhandled cases
}
Py_UNREACHABLE();
}
static int
@ -180,7 +182,7 @@ validate_constant(struct validator *state, PyObject *value)
static int
validate_expr(struct validator *state, expr_ty exp, expr_context_ty ctx)
{
int ret;
int ret = -1;
if (++state->recursion_depth > state->recursion_limit) {
PyErr_SetString(PyExc_RecursionError,
"maximum recursion depth exceeded during compilation");
@ -351,33 +353,215 @@ validate_expr(struct validator *state, expr_ty exp, expr_context_ty ctx)
case NamedExpr_kind:
ret = validate_expr(state, exp->v.NamedExpr.value, Load);
break;
case MatchAs_kind:
PyErr_SetString(PyExc_ValueError,
"MatchAs is only valid in match_case patterns");
return 0;
case MatchOr_kind:
PyErr_SetString(PyExc_ValueError,
"MatchOr is only valid in match_case patterns");
return 0;
/* This last case doesn't have any checking. */
case Name_kind:
ret = 1;
break;
default:
// No default case so compiler emits warning for unhandled cases
}
if (ret < 0) {
PyErr_SetString(PyExc_SystemError, "unexpected expression");
return 0;
ret = 0;
}
state->recursion_depth--;
return ret;
}
// Note: the ensure_literal_* functions are only used to validate a restricted
// set of non-recursive literals that have already been checked with
// validate_expr, so they don't accept the validator state
static int
validate_pattern(expr_ty p)
ensure_literal_number(expr_ty exp, bool allow_real, bool allow_imaginary)
{
// Coming soon (thanks Batuhan)!
assert(exp->kind == Constant_kind);
PyObject *value = exp->v.Constant.value;
return (allow_real && PyFloat_CheckExact(value)) ||
(allow_real && PyLong_CheckExact(value)) ||
(allow_imaginary && PyComplex_CheckExact(value));
}
static int
ensure_literal_negative(expr_ty exp, bool allow_real, bool allow_imaginary)
{
assert(exp->kind == UnaryOp_kind);
// Must be negation ...
if (exp->v.UnaryOp.op != USub) {
return 0;
}
// ... of a constant ...
expr_ty operand = exp->v.UnaryOp.operand;
if (operand->kind != Constant_kind) {
return 0;
}
// ... number
return ensure_literal_number(operand, allow_real, allow_imaginary);
}
static int
ensure_literal_complex(expr_ty exp)
{
assert(exp->kind == BinOp_kind);
expr_ty left = exp->v.BinOp.left;
expr_ty right = exp->v.BinOp.right;
// Ensure op is addition or subtraction
if (exp->v.BinOp.op != Add && exp->v.BinOp.op != Sub) {
return 0;
}
// Check LHS is a real number (potentially signed)
switch (left->kind)
{
case Constant_kind:
if (!ensure_literal_number(left, /*real=*/true, /*imaginary=*/false)) {
return 0;
}
break;
case UnaryOp_kind:
if (!ensure_literal_negative(left, /*real=*/true, /*imaginary=*/false)) {
return 0;
}
break;
default:
return 0;
}
// Check RHS is an imaginary number (no separate sign allowed)
switch (right->kind)
{
case Constant_kind:
if (!ensure_literal_number(right, /*real=*/false, /*imaginary=*/true)) {
return 0;
}
break;
default:
return 0;
}
return 1;
}
static int
validate_pattern_match_value(struct validator *state, expr_ty exp)
{
if (!validate_expr(state, exp, Load)) {
return 0;
}
switch (exp->kind)
{
case Constant_kind:
case Attribute_kind:
// Constants and attribute lookups are always permitted
return 1;
case UnaryOp_kind:
// Negated numbers are permitted (whether real or imaginary)
// Compiler will complain if AST folding doesn't create a constant
if (ensure_literal_negative(exp, /*real=*/true, /*imaginary=*/true)) {
return 1;
}
break;
case BinOp_kind:
// Complex literals are permitted
// Compiler will complain if AST folding doesn't create a constant
if (ensure_literal_complex(exp)) {
return 1;
}
break;
default:
break;
}
PyErr_SetString(PyExc_SyntaxError,
"patterns may only match literals and attribute lookups");
return 0;
}
static int
validate_pattern(struct validator *state, pattern_ty p)
{
int ret = -1;
if (++state->recursion_depth > state->recursion_limit) {
PyErr_SetString(PyExc_RecursionError,
"maximum recursion depth exceeded during compilation");
return 0;
}
// Coming soon: https://bugs.python.org/issue43897 (thanks Batuhan)!
// TODO: Ensure no subnodes use "_" as an ordinary identifier
switch (p->kind) {
case MatchValue_kind:
ret = validate_pattern_match_value(state, p->v.MatchValue.value);
break;
case MatchSingleton_kind:
// TODO: Check constant is specifically None, True, or False
ret = validate_constant(state, p->v.MatchSingleton.value);
break;
case MatchSequence_kind:
// TODO: Validate all subpatterns
// return validate_patterns(state, p->v.MatchSequence.patterns);
ret = 1;
break;
case MatchMapping_kind:
// TODO: check "rest" target name is valid
if (asdl_seq_LEN(p->v.MatchMapping.keys) != asdl_seq_LEN(p->v.MatchMapping.patterns)) {
PyErr_SetString(PyExc_ValueError,
"MatchMapping doesn't have the same number of keys as patterns");
return 0;
}
// null_ok=0 for key expressions, as rest-of-mapping is captured in "rest"
// TODO: replace with more restrictive expression validator, as per MatchValue above
if (!validate_exprs(state, p->v.MatchMapping.keys, Load, /*null_ok=*/ 0)) {
return 0;
}
// TODO: Validate all subpatterns
// ret = validate_patterns(state, p->v.MatchMapping.patterns);
ret = 1;
break;
case MatchClass_kind:
if (asdl_seq_LEN(p->v.MatchClass.kwd_attrs) != asdl_seq_LEN(p->v.MatchClass.kwd_patterns)) {
PyErr_SetString(PyExc_ValueError,
"MatchClass doesn't have the same number of keyword attributes as patterns");
return 0;
}
// TODO: Restrict cls lookup to being a name or attribute
if (!validate_expr(state, p->v.MatchClass.cls, Load)) {
return 0;
}
// TODO: Validate all subpatterns
// return validate_patterns(state, p->v.MatchClass.patterns) &&
// validate_patterns(state, p->v.MatchClass.kwd_patterns);
ret = 1;
break;
case MatchStar_kind:
// TODO: check target name is valid
ret = 1;
break;
case MatchAs_kind:
// TODO: check target name is valid
if (p->v.MatchAs.pattern == NULL) {
ret = 1;
}
else if (p->v.MatchAs.name == NULL) {
PyErr_SetString(PyExc_ValueError,
"MatchAs must specify a target name if a pattern is given");
return 0;
}
else {
ret = validate_pattern(state, p->v.MatchAs.pattern);
}
break;
case MatchOr_kind:
// TODO: Validate all subpatterns
// return validate_patterns(state, p->v.MatchOr.patterns);
ret = 1;
break;
// No default case, so the compiler will emit a warning if new pattern
// kinds are added without being handled here
}
if (ret < 0) {
PyErr_SetString(PyExc_SystemError, "unexpected pattern");
ret = 0;
}
state->recursion_depth--;
return ret;
}
static int
_validate_nonempty_seq(asdl_seq *seq, const char *what, const char *owner)
{
@ -404,7 +588,7 @@ validate_body(struct validator *state, asdl_stmt_seq *body, const char *owner)
static int
validate_stmt(struct validator *state, stmt_ty stmt)
{
int ret;
int ret = -1;
Py_ssize_t i;
if (++state->recursion_depth > state->recursion_limit) {
PyErr_SetString(PyExc_RecursionError,
@ -502,7 +686,7 @@ validate_stmt(struct validator *state, stmt_ty stmt)
}
for (i = 0; i < asdl_seq_LEN(stmt->v.Match.cases); i++) {
match_case_ty m = asdl_seq_GET(stmt->v.Match.cases, i);
if (!validate_pattern(m->pattern)
if (!validate_pattern(state, m->pattern)
|| (m->guard && !validate_expr(state, m->guard, Load))
|| !validate_body(state, m->body, "match_case")) {
return 0;
@ -582,9 +766,11 @@ validate_stmt(struct validator *state, stmt_ty stmt)
case Continue_kind:
ret = 1;
break;
default:
// No default case so compiler emits warning for unhandled cases
}
if (ret < 0) {
PyErr_SetString(PyExc_SystemError, "unexpected statement");
return 0;
ret = 0;
}
state->recursion_depth--;
return ret;
@ -635,7 +821,7 @@ validate_exprs(struct validator *state, asdl_expr_seq *exprs, expr_context_ty ct
int
_PyAST_Validate(mod_ty mod)
{
int res = 0;
int res = -1;
struct validator state;
PyThreadState *tstate;
int recursion_limit = Py_GetRecursionLimit();
@ -663,10 +849,16 @@ _PyAST_Validate(mod_ty mod)
case Expression_kind:
res = validate_expr(&state, mod->v.Expression.body, Load);
break;
default:
PyErr_SetString(PyExc_SystemError, "impossible module node");
res = 0;
case FunctionType_kind:
res = validate_exprs(&state, mod->v.FunctionType.argtypes, Load, /*null_ok=*/0) &&
validate_expr(&state, mod->v.FunctionType.returns, Load);
break;
// No default case so compiler emits warning for unhandled cases
}
if (res < 0) {
PyErr_SetString(PyExc_SystemError, "impossible module node");
return 0;
}
/* Check that the recursion depth counting balanced correctly */

124
Python/ast_opt.c
View file

@ -411,7 +411,7 @@ static int astfold_arg(arg_ty node_, PyArena *ctx_, _PyASTOptimizeState *state);
static int astfold_withitem(withitem_ty node_, PyArena *ctx_, _PyASTOptimizeState *state);
static int astfold_excepthandler(excepthandler_ty node_, PyArena *ctx_, _PyASTOptimizeState *state);
static int astfold_match_case(match_case_ty node_, PyArena *ctx_, _PyASTOptimizeState *state);
static int astfold_pattern(expr_ty node_, PyArena *ctx_, _PyASTOptimizeState *state);
static int astfold_pattern(pattern_ty node_, PyArena *ctx_, _PyASTOptimizeState *state);
#define CALL(FUNC, TYPE, ARG) \
if (!FUNC((ARG), ctx_, state)) \
@ -602,10 +602,6 @@ astfold_expr(expr_ty node_, PyArena *ctx_, _PyASTOptimizeState *state)
case Constant_kind:
// Already a constant, nothing further to do
break;
case MatchAs_kind:
case MatchOr_kind:
// These can't occur outside of patterns.
Py_UNREACHABLE();
// No default case, so the compiler will emit a warning if new expression
// kinds are added without being handled here
}
@ -797,112 +793,48 @@ astfold_withitem(withitem_ty node_, PyArena *ctx_, _PyASTOptimizeState *state)
}
static int
astfold_pattern_negative(expr_ty node_, PyArena *ctx_, _PyASTOptimizeState *state)
astfold_pattern(pattern_ty node_, PyArena *ctx_, _PyASTOptimizeState *state)
{
assert(node_->kind == UnaryOp_kind);
assert(node_->v.UnaryOp.op == USub);
assert(node_->v.UnaryOp.operand->kind == Constant_kind);
PyObject *value = node_->v.UnaryOp.operand->v.Constant.value;
assert(PyComplex_CheckExact(value) ||
PyFloat_CheckExact(value) ||
PyLong_CheckExact(value));
PyObject *negated = PyNumber_Negative(value);
if (negated == NULL) {
// Currently, this is really only used to form complex/negative numeric
// constants in MatchValue and MatchMapping nodes
// We still recurse into all subexpressions and subpatterns anyway
if (++state->recursion_depth > state->recursion_limit) {
PyErr_SetString(PyExc_RecursionError,
"maximum recursion depth exceeded during compilation");
return 0;
}
assert(PyComplex_CheckExact(negated) ||
PyFloat_CheckExact(negated) ||
PyLong_CheckExact(negated));
return make_const(node_, negated, ctx_);
}
static int
astfold_pattern_complex(expr_ty node_, PyArena *ctx_, _PyASTOptimizeState *state)
{
expr_ty left = node_->v.BinOp.left;
expr_ty right = node_->v.BinOp.right;
if (left->kind == UnaryOp_kind) {
CALL(astfold_pattern_negative, expr_ty, left);
}
assert(left->kind = Constant_kind);
assert(right->kind = Constant_kind);
// LHS must be real, RHS must be imaginary:
if (!(PyFloat_CheckExact(left->v.Constant.value) ||
PyLong_CheckExact(left->v.Constant.value)) ||
!PyComplex_CheckExact(right->v.Constant.value))
{
// Not actually valid, but it's the compiler's job to complain:
return 1;
}
PyObject *new;
if (node_->v.BinOp.op == Add) {
new = PyNumber_Add(left->v.Constant.value, right->v.Constant.value);
}
else {
assert(node_->v.BinOp.op == Sub);
new = PyNumber_Subtract(left->v.Constant.value, right->v.Constant.value);
}
if (new == NULL) {
return 0;
}
assert(PyComplex_CheckExact(new));
return make_const(node_, new, ctx_);
}
static int
astfold_pattern_keyword(keyword_ty node_, PyArena *ctx_, _PyASTOptimizeState *state)
{
CALL(astfold_pattern, expr_ty, node_->value);
return 1;
}
static int
astfold_pattern(expr_ty node_, PyArena *ctx_, _PyASTOptimizeState *state)
{
// Don't blindly optimize the pattern as an expr; it plays by its own rules!
// Currently, this is only used to form complex/negative numeric constants.
switch (node_->kind) {
case Attribute_kind:
case MatchValue_kind:
CALL(astfold_expr, expr_ty, node_->v.MatchValue.value);
break;
case BinOp_kind:
CALL(astfold_pattern_complex, expr_ty, node_);
case MatchSingleton_kind:
break;
case Call_kind:
CALL_SEQ(astfold_pattern, expr, node_->v.Call.args);
CALL_SEQ(astfold_pattern_keyword, keyword, node_->v.Call.keywords);
case MatchSequence_kind:
CALL_SEQ(astfold_pattern, pattern, node_->v.MatchSequence.patterns);
break;
case Constant_kind:
case MatchMapping_kind:
CALL_SEQ(astfold_expr, expr, node_->v.MatchMapping.keys);
CALL_SEQ(astfold_pattern, pattern, node_->v.MatchMapping.patterns);
break;
case Dict_kind:
CALL_SEQ(astfold_pattern, expr, node_->v.Dict.keys);
CALL_SEQ(astfold_pattern, expr, node_->v.Dict.values);
case MatchClass_kind:
CALL(astfold_expr, expr_ty, node_->v.MatchClass.cls);
CALL_SEQ(astfold_pattern, pattern, node_->v.MatchClass.patterns);
CALL_SEQ(astfold_pattern, pattern, node_->v.MatchClass.kwd_patterns);
break;
// Not actually valid, but it's the compiler's job to complain:
case JoinedStr_kind:
break;
case List_kind:
CALL_SEQ(astfold_pattern, expr, node_->v.List.elts);
case MatchStar_kind:
break;
case MatchAs_kind:
CALL(astfold_pattern, expr_ty, node_->v.MatchAs.pattern);
if (node_->v.MatchAs.pattern) {
CALL(astfold_pattern, expr_ty, node_->v.MatchAs.pattern);
}
break;
case MatchOr_kind:
CALL_SEQ(astfold_pattern, expr, node_->v.MatchOr.patterns);
CALL_SEQ(astfold_pattern, pattern, node_->v.MatchOr.patterns);
break;
case Name_kind:
break;
case Starred_kind:
CALL(astfold_pattern, expr_ty, node_->v.Starred.value);
break;
case Tuple_kind:
CALL_SEQ(astfold_pattern, expr, node_->v.Tuple.elts);
break;
case UnaryOp_kind:
CALL(astfold_pattern_negative, expr_ty, node_);
break;
default:
Py_UNREACHABLE();
// No default case, so the compiler will emit a warning if new pattern
// kinds are added without being handled here
}
state->recursion_depth--;
return 1;
}

13
Python/ast_unparse.c
View file

@ -3,6 +3,11 @@
#include <float.h> // DBL_MAX_10_EXP
#include <stdbool.h>
/* This limited unparser is used to convert annotations back to strings
* during compilation rather than being a full AST unparser.
* See ast.unparse for a full unparser (written in Python)
*/
static PyObject *_str_open_br;
static PyObject *_str_dbl_open_br;
static PyObject *_str_close_br;
@ -912,11 +917,11 @@ append_ast_expr(_PyUnicodeWriter *writer, expr_ty e, int level)
return append_ast_tuple(writer, e, level);
case NamedExpr_kind:
return append_named_expr(writer, e, level);
default:
PyErr_SetString(PyExc_SystemError,
"unknown expression kind");
return -1;
// No default so compiler emits a warning for unhandled cases
}
PyErr_SetString(PyExc_SystemError,
"unknown expression kind");
return -1;
}
static int

6
Python/bltinmodule.c
View file

@ -831,11 +831,7 @@ builtin_compile_impl(PyObject *module, PyObject *source, PyObject *filename,
if (arena == NULL)
goto error;
mod = PyAST_obj2mod(source, arena, compile_mode);
if (mod == NULL) {
_PyArena_Free(arena);
goto error;
}
if (!_PyAST_Validate(mod)) {
if (mod == NULL || !_PyAST_Validate(mod)) {
_PyArena_Free(arena);
goto error;
}

383
Python/compile.c
View file

@ -280,9 +280,9 @@ static int compiler_async_comprehension_generator(
int depth,
expr_ty elt, expr_ty val, int type);
static int compiler_pattern(struct compiler *, expr_ty, pattern_context *);
static int compiler_pattern(struct compiler *, pattern_ty, pattern_context *);
static int compiler_match(struct compiler *, stmt_ty);
static int compiler_pattern_subpattern(struct compiler *, expr_ty,
static int compiler_pattern_subpattern(struct compiler *, pattern_ty,
pattern_context *);
static PyCodeObject *assemble(struct compiler *, int addNone);
@ -5263,10 +5263,6 @@ compiler_visit_expr1(struct compiler *c, expr_ty e)
return compiler_list(c, e);
case Tuple_kind:
return compiler_tuple(c, e);
case MatchAs_kind:
case MatchOr_kind:
// Can only occur in patterns, which are handled elsewhere.
Py_UNREACHABLE();
}
return 1;
}
@ -5600,16 +5596,22 @@ compiler_slice(struct compiler *c, expr_ty s)
// that it's much easier to smooth out any redundant pushing, popping, and
// jumping in the peephole optimizer than to detect or predict it here.
#define WILDCARD_CHECK(N) \
((N)->kind == Name_kind && \
_PyUnicode_EqualToASCIIString((N)->v.Name.id, "_"))
((N)->kind == MatchAs_kind && !(N)->v.MatchAs.name)
#define WILDCARD_STAR_CHECK(N) \
((N)->kind == MatchStar_kind && !(N)->v.MatchStar.name)
// Limit permitted subexpressions, even if the parser & AST validator let them through
#define MATCH_VALUE_EXPR(N) \
((N)->kind == Constant_kind || (N)->kind == Attribute_kind)
static int
pattern_helper_store_name(struct compiler *c, identifier n, pattern_context *pc)
{
assert(!_PyUnicode_EqualToASCIIString(n, "_"));
if (forbidden_name(c, n, Store)) {
return 0;
}
// Can't assign to the same name twice:
if (pc->stores == NULL) {
RETURN_IF_FALSE(pc->stores = PySet_New(NULL));
@ -5631,16 +5633,43 @@ pattern_helper_store_name(struct compiler *c, identifier n, pattern_context *pc)
static int
pattern_helper_sequence_unpack(struct compiler *c, asdl_expr_seq *values,
pattern_unpack_helper(struct compiler *c, asdl_pattern_seq *elts)
{
Py_ssize_t n = asdl_seq_LEN(elts);
int seen_star = 0;
for (Py_ssize_t i = 0; i < n; i++) {
pattern_ty elt = asdl_seq_GET(elts, i);
if (elt->kind == MatchStar_kind && !seen_star) {
if ((i >= (1 << 8)) ||
(n-i-1 >= (INT_MAX >> 8)))
return compiler_error(c,
"too many expressions in "
"star-unpacking sequence pattern");
ADDOP_I(c, UNPACK_EX, (i + ((n-i-1) << 8)));
seen_star = 1;
}
else if (elt->kind == MatchStar_kind) {
return compiler_error(c,
"multiple starred expressions in sequence pattern");
}
}
if (!seen_star) {
ADDOP_I(c, UNPACK_SEQUENCE, n);
}
return 1;
}
static int
pattern_helper_sequence_unpack(struct compiler *c, asdl_pattern_seq *patterns,
Py_ssize_t star, pattern_context *pc)
{
RETURN_IF_FALSE(unpack_helper(c, values));
RETURN_IF_FALSE(pattern_unpack_helper(c, patterns));
// We've now got a bunch of new subjects on the stack. If any of them fail
// to match, we need to pop everything else off, then finally push False.
// fails is an array of blocks that correspond to the necessary amount of
// popping for each element:
basicblock **fails;
Py_ssize_t size = asdl_seq_LEN(values);
Py_ssize_t size = asdl_seq_LEN(patterns);
fails = (basicblock **)PyObject_Malloc(sizeof(basicblock*) * size);
if (fails == NULL) {
PyErr_NoMemory();
@ -5655,12 +5684,9 @@ pattern_helper_sequence_unpack(struct compiler *c, asdl_expr_seq *values,
}
}
for (Py_ssize_t i = 0; i < size; i++) {
expr_ty value = asdl_seq_GET(values, i);
if (i == star) {
assert(value->kind == Starred_kind);
value = value->v.Starred.value;
}
if (!compiler_pattern_subpattern(c, value, pc) ||
pattern_ty pattern = asdl_seq_GET(patterns, i);
assert((i == star) == (pattern->kind == MatchStar_kind));
if (!compiler_pattern_subpattern(c, pattern, pc) ||
!compiler_addop_j(c, POP_JUMP_IF_FALSE, fails[i]) ||
compiler_next_block(c) == NULL)
{
@ -5703,21 +5729,20 @@ error:
// UNPACK_SEQUENCE / UNPACK_EX. This is more efficient for patterns with a
// starred wildcard like [first, *_] / [first, *_, last] / [*_, last] / etc.
static int
pattern_helper_sequence_subscr(struct compiler *c, asdl_expr_seq *values,
pattern_helper_sequence_subscr(struct compiler *c, asdl_pattern_seq *patterns,
Py_ssize_t star, pattern_context *pc)
{
basicblock *end, *fail_pop_1;
RETURN_IF_FALSE(end = compiler_new_block(c));
RETURN_IF_FALSE(fail_pop_1 = compiler_new_block(c));
Py_ssize_t size = asdl_seq_LEN(values);
Py_ssize_t size = asdl_seq_LEN(patterns);
for (Py_ssize_t i = 0; i < size; i++) {
expr_ty value = asdl_seq_GET(values, i);
if (WILDCARD_CHECK(value)) {
pattern_ty pattern = asdl_seq_GET(patterns, i);
if (WILDCARD_CHECK(pattern)) {
continue;
}
if (i == star) {
assert(value->kind == Starred_kind);
assert(WILDCARD_CHECK(value->v.Starred.value));
assert(WILDCARD_STAR_CHECK(pattern));
continue;
}
ADDOP(c, DUP_TOP);
@ -5732,7 +5757,7 @@ pattern_helper_sequence_subscr(struct compiler *c, asdl_expr_seq *values,
ADDOP(c, BINARY_SUBTRACT);
}
ADDOP(c, BINARY_SUBSCR);
RETURN_IF_FALSE(compiler_pattern_subpattern(c, value, pc));
RETURN_IF_FALSE(compiler_pattern_subpattern(c, pattern, pc));
ADDOP_JUMP(c, POP_JUMP_IF_FALSE, fail_pop_1);
NEXT_BLOCK(c);
}
@ -5746,10 +5771,9 @@ pattern_helper_sequence_subscr(struct compiler *c, asdl_expr_seq *values,
return 1;
}
// Like compiler_pattern, but turn off checks for irrefutability.
static int
compiler_pattern_subpattern(struct compiler *c, expr_ty p, pattern_context *pc)
compiler_pattern_subpattern(struct compiler *c, pattern_ty p, pattern_context *pc)
{
int allow_irrefutable = pc->allow_irrefutable;
pc->allow_irrefutable = 1;
@ -5758,11 +5782,43 @@ compiler_pattern_subpattern(struct compiler *c, expr_ty p, pattern_context *pc)
return 1;
}
static int
compiler_pattern_capture(struct compiler *c, identifier n, pattern_context *pc)
{
RETURN_IF_FALSE(pattern_helper_store_name(c, n, pc));
ADDOP_LOAD_CONST(c, Py_True);
return 1;
}
static int
compiler_pattern_as(struct compiler *c, expr_ty p, pattern_context *pc)
compiler_pattern_wildcard(struct compiler *c, pattern_ty p, pattern_context *pc)
{
assert(p->kind == MatchAs_kind);
if (!pc->allow_irrefutable) {
// Whoops, can't have a wildcard here!
const char *e = "wildcard makes remaining patterns unreachable";
return compiler_error(c, e);
}
ADDOP(c, POP_TOP);
ADDOP_LOAD_CONST(c, Py_True);
return 1;
}
static int
compiler_pattern_as(struct compiler *c, pattern_ty p, pattern_context *pc)
{
assert(p->kind == MatchAs_kind);
if (p->v.MatchAs.name == NULL) {
return compiler_pattern_wildcard(c, p, pc);
}
if (p->v.MatchAs.pattern == NULL) {
if (!pc->allow_irrefutable) {
// Whoops, can't have a name capture here!
const char *e = "name capture %R makes remaining patterns unreachable";
return compiler_error(c, e, p->v.MatchAs.name);
}
return compiler_pattern_capture(c, p->v.MatchAs.name, pc);
}
basicblock *end, *fail_pop_1;
RETURN_IF_FALSE(end = compiler_new_block(c));
RETURN_IF_FALSE(fail_pop_1 = compiler_new_block(c));
@ -5782,71 +5838,101 @@ compiler_pattern_as(struct compiler *c, expr_ty p, pattern_context *pc)
return 1;
}
static int
compiler_pattern_capture(struct compiler *c, expr_ty p, pattern_context *pc)
compiler_pattern_star(struct compiler *c, pattern_ty p, pattern_context *pc)
{
assert(p->kind == Name_kind);
assert(p->v.Name.ctx == Store);
assert(!WILDCARD_CHECK(p));
assert(p->kind == MatchStar_kind);
if (!pc->allow_irrefutable) {
// Whoops, can't have a name capture here!
const char *e = "name capture %R makes remaining patterns unreachable";
return compiler_error(c, e, p->v.Name.id);
// Whoops, can't have a star capture here!
const char *e = "star captures are only allowed as part of sequence patterns";
return compiler_error(c, e);
}
RETURN_IF_FALSE(pattern_helper_store_name(c, p->v.Name.id, pc));
ADDOP_LOAD_CONST(c, Py_True);
return 1;
return compiler_pattern_capture(c, p->v.MatchStar.name, pc);
}
static int
validate_kwd_attrs(struct compiler *c, asdl_identifier_seq *attrs, asdl_pattern_seq* patterns)
{
// Any errors will point to the pattern rather than the arg name as the
// parser is only supplying identifiers rather than Name or keyword nodes
Py_ssize_t nattrs = asdl_seq_LEN(attrs);
for (Py_ssize_t i = 0; i < nattrs; i++) {
identifier attr = ((identifier)asdl_seq_GET(attrs, i));
c->u->u_col_offset = ((pattern_ty) asdl_seq_GET(patterns, i))->col_offset;
if (forbidden_name(c, attr, Store)) {
return -1;
}
for (Py_ssize_t j = i + 1; j < nattrs; j++) {
identifier other = ((identifier)asdl_seq_GET(attrs, j));
if (!PyUnicode_Compare(attr, other)) {
c->u->u_col_offset = ((pattern_ty) asdl_seq_GET(patterns, j))->col_offset;
compiler_error(c, "attribute name repeated in class pattern: %U", attr);
return -1;
}
}
}
return 0;
}
static int
compiler_pattern_class(struct compiler *c, expr_ty p, pattern_context *pc)
compiler_pattern_class(struct compiler *c, pattern_ty p, pattern_context *pc)
{
asdl_expr_seq *args = p->v.Call.args;
asdl_keyword_seq *kwargs = p->v.Call.keywords;
Py_ssize_t nargs = asdl_seq_LEN(args);
Py_ssize_t nkwargs = asdl_seq_LEN(kwargs);
if (INT_MAX < nargs || INT_MAX < nargs + nkwargs - 1) {
const char *e = "too many sub-patterns in class pattern %R";
return compiler_error(c, e, p->v.Call.func);
assert(p->kind == MatchClass_kind);
asdl_pattern_seq *patterns = p->v.MatchClass.patterns;
asdl_identifier_seq *kwd_attrs = p->v.MatchClass.kwd_attrs;
asdl_pattern_seq *kwd_patterns = p->v.MatchClass.kwd_patterns;
Py_ssize_t nargs = asdl_seq_LEN(patterns);
Py_ssize_t nattrs = asdl_seq_LEN(kwd_attrs);
Py_ssize_t nkwd_patterns = asdl_seq_LEN(kwd_patterns);
if (nattrs != nkwd_patterns) {
// AST validator shouldn't let this happen, but if it does,
// just fail, don't crash out of the interpreter
const char * e = "kwd_attrs (%d) / kwd_patterns (%d) length mismatch in class pattern";
return compiler_error(c, e, nattrs, nkwd_patterns);
}
if (INT_MAX < nargs || INT_MAX < nargs + nattrs - 1) {
const char *e = "too many sub-patterns in class pattern %R";
return compiler_error(c, e, p->v.MatchClass.cls);
}
if (nattrs) {
RETURN_IF_FALSE(!validate_kwd_attrs(c, kwd_attrs, kwd_patterns));
c->u->u_col_offset = p->col_offset; // validate_kwd_attrs moves this
}
RETURN_IF_FALSE(!validate_keywords(c, kwargs));
basicblock *end, *fail_pop_1;
RETURN_IF_FALSE(end = compiler_new_block(c));
RETURN_IF_FALSE(fail_pop_1 = compiler_new_block(c));
VISIT(c, expr, p->v.Call.func);
PyObject *kwnames;
RETURN_IF_FALSE(kwnames = PyTuple_New(nkwargs));
VISIT(c, expr, p->v.MatchClass.cls);
PyObject *attr_names;
RETURN_IF_FALSE(attr_names = PyTuple_New(nattrs));
Py_ssize_t i;
for (i = 0; i < nkwargs; i++) {
PyObject *name = ((keyword_ty) asdl_seq_GET(kwargs, i))->arg;
for (i = 0; i < nattrs; i++) {
PyObject *name = asdl_seq_GET(kwd_attrs, i);
Py_INCREF(name);
PyTuple_SET_ITEM(kwnames, i, name);
PyTuple_SET_ITEM(attr_names, i, name);
}
ADDOP_LOAD_CONST_NEW(c, kwnames);
ADDOP_LOAD_CONST_NEW(c, attr_names);
ADDOP_I(c, MATCH_CLASS, nargs);
ADDOP_JUMP(c, POP_JUMP_IF_FALSE, fail_pop_1);
NEXT_BLOCK(c);
// TOS is now a tuple of (nargs + nkwargs) attributes.
for (i = 0; i < nargs + nkwargs; i++) {
expr_ty arg;
for (i = 0; i < nargs + nattrs; i++) {
pattern_ty pattern;
if (i < nargs) {
// Positional:
arg = asdl_seq_GET(args, i);
pattern = asdl_seq_GET(patterns, i);
}
else {
// Keyword:
arg = ((keyword_ty) asdl_seq_GET(kwargs, i - nargs))->value;
pattern = asdl_seq_GET(kwd_patterns, i - nargs);
}
if (WILDCARD_CHECK(arg)) {
if (WILDCARD_CHECK(pattern)) {
continue;
}
// Get the i-th attribute, and match it against the i-th pattern:
ADDOP(c, DUP_TOP);
ADDOP_LOAD_CONST_NEW(c, PyLong_FromSsize_t(i));
ADDOP(c, BINARY_SUBSCR);
RETURN_IF_FALSE(compiler_pattern_subpattern(c, arg, pc));
RETURN_IF_FALSE(compiler_pattern_subpattern(c, pattern, pc));
ADDOP_JUMP(c, POP_JUMP_IF_FALSE, fail_pop_1);
NEXT_BLOCK(c);
}
@ -5861,36 +5947,30 @@ compiler_pattern_class(struct compiler *c, expr_ty p, pattern_context *pc)
return 1;
}
static int
compiler_pattern_literal(struct compiler *c, expr_ty p, pattern_context *pc)
{
assert(p->kind == Constant_kind);
PyObject *v = p->v.Constant.value;
ADDOP_LOAD_CONST(c, v);
// Literal True, False, and None are compared by identity. All others use
// equality:
ADDOP_COMPARE(c, (v == Py_None || PyBool_Check(v)) ? Is : Eq);
return 1;
}
static int
compiler_pattern_mapping(struct compiler *c, expr_ty p, pattern_context *pc)
compiler_pattern_mapping(struct compiler *c, pattern_ty p, pattern_context *pc)
{
assert(p->kind == MatchMapping_kind);
basicblock *end, *fail_pop_1, *fail_pop_3;
RETURN_IF_FALSE(end = compiler_new_block(c));
RETURN_IF_FALSE(fail_pop_1 = compiler_new_block(c));
RETURN_IF_FALSE(fail_pop_3 = compiler_new_block(c));
asdl_expr_seq *keys = p->v.Dict.keys;
asdl_expr_seq *values = p->v.Dict.values;
Py_ssize_t size = asdl_seq_LEN(values);
// A starred pattern will be a keyless value. It is guaranteed to be last:
int star = size ? !asdl_seq_GET(keys, size - 1) : 0;
asdl_expr_seq *keys = p->v.MatchMapping.keys;
asdl_pattern_seq *patterns = p->v.MatchMapping.patterns;
Py_ssize_t size = asdl_seq_LEN(keys);
Py_ssize_t npatterns = asdl_seq_LEN(patterns);
if (size != npatterns) {
// AST validator shouldn't let this happen, but if it does,
// just fail, don't crash out of the interpreter
const char * e = "keys (%d) / patterns (%d) length mismatch in mapping pattern";
return compiler_error(c, e, size, npatterns);
}
// We have a double-star target if "rest" is set
PyObject *star_target = p->v.MatchMapping.rest;
ADDOP(c, MATCH_MAPPING);
ADDOP_JUMP(c, POP_JUMP_IF_FALSE, fail_pop_1);
NEXT_BLOCK(c);
if (!size) {
if (!size && !star_target) {
// If the pattern is just "{}", we're done!
ADDOP(c, POP_TOP);
ADDOP_LOAD_CONST(c, Py_True);
@ -5901,53 +5981,57 @@ compiler_pattern_mapping(struct compiler *c, expr_ty p, pattern_context *pc)
compiler_use_next_block(c, end);
return 1;
}
if (size - star) {
if (size) {
// If the pattern has any keys in it, perform a length check:
ADDOP(c, GET_LEN);
ADDOP_LOAD_CONST_NEW(c, PyLong_FromSsize_t(size - star));
ADDOP_LOAD_CONST_NEW(c, PyLong_FromSsize_t(size));
ADDOP_COMPARE(c, GtE);
ADDOP_JUMP(c, POP_JUMP_IF_FALSE, fail_pop_1);
NEXT_BLOCK(c);
}
if (INT_MAX < size - star - 1) {
if (INT_MAX < size - 1) {
return compiler_error(c, "too many sub-patterns in mapping pattern");
}
// Collect all of the keys into a tuple for MATCH_KEYS and
// COPY_DICT_WITHOUT_KEYS. They can either be dotted names or literals:
for (Py_ssize_t i = 0; i < size - star; i++) {
for (Py_ssize_t i = 0; i < size; i++) {
expr_ty key = asdl_seq_GET(keys, i);
if (key == NULL) {
const char *e = "can't use starred name here "
"(consider moving to end)";
const char *e = "can't use NULL keys in MatchMapping "
"(set 'rest' parameter instead)";
c->u->u_col_offset = ((pattern_ty) asdl_seq_GET(patterns, i))->col_offset;
return compiler_error(c, e);
}
if (!MATCH_VALUE_EXPR(key)) {
const char *e = "mapping pattern keys may only match literals and attribute lookups";
return compiler_error(c, e);
}
VISIT(c, expr, key);
}
ADDOP_I(c, BUILD_TUPLE, size - star);
ADDOP_I(c, BUILD_TUPLE, size);
ADDOP(c, MATCH_KEYS);
ADDOP_JUMP(c, POP_JUMP_IF_FALSE, fail_pop_3);
NEXT_BLOCK(c);
// So far so good. There's now a tuple of values on the stack to match
// sub-patterns against:
for (Py_ssize_t i = 0; i < size - star; i++) {
expr_ty value = asdl_seq_GET(values, i);
if (WILDCARD_CHECK(value)) {
for (Py_ssize_t i = 0; i < size; i++) {
pattern_ty pattern = asdl_seq_GET(patterns, i);
if (WILDCARD_CHECK(pattern)) {
continue;
}
ADDOP(c, DUP_TOP);
ADDOP_LOAD_CONST_NEW(c, PyLong_FromSsize_t(i));
ADDOP(c, BINARY_SUBSCR);
RETURN_IF_FALSE(compiler_pattern_subpattern(c, value, pc));
RETURN_IF_FALSE(compiler_pattern_subpattern(c, pattern, pc));
ADDOP_JUMP(c, POP_JUMP_IF_FALSE, fail_pop_3);
NEXT_BLOCK(c);
}
// If we get this far, it's a match! We're done with that tuple of values.
ADDOP(c, POP_TOP);
if (star) {
// If we had a starred name, bind a dict of remaining items to it:
if (star_target) {
// If we have a starred name, bind a dict of remaining items to it:
ADDOP(c, COPY_DICT_WITHOUT_KEYS);
PyObject *id = asdl_seq_GET(values, size - 1)->v.Name.id;
RETURN_IF_FALSE(pattern_helper_store_name(c, id, pc));
RETURN_IF_FALSE(pattern_helper_store_name(c, star_target, pc));
}
else {
// Otherwise, we don't care about this tuple of keys anymore:
@ -5970,9 +6054,8 @@ compiler_pattern_mapping(struct compiler *c, expr_ty p, pattern_context *pc)
return 1;
}
static int
compiler_pattern_or(struct compiler *c, expr_ty p, pattern_context *pc)
compiler_pattern_or(struct compiler *c, pattern_ty p, pattern_context *pc)
{
assert(p->kind == MatchOr_kind);
// control is the set of names bound by the first alternative. If all of the
@ -5988,7 +6071,7 @@ compiler_pattern_or(struct compiler *c, expr_ty p, pattern_context *pc)
int allow_irrefutable = pc->allow_irrefutable;
for (Py_ssize_t i = 0; i < size; i++) {
// NOTE: Can't use our nice returning macros in here: they'll leak sets!
expr_ty alt = asdl_seq_GET(p->v.MatchOr.patterns, i);
pattern_ty alt = asdl_seq_GET(p->v.MatchOr.patterns, i);
pc->stores = PySet_New(stores_init);
// An irrefutable sub-pattern must be last, if it is allowed at all:
int is_last = i == size - 1;
@ -6044,28 +6127,28 @@ fail:
static int
compiler_pattern_sequence(struct compiler *c, expr_ty p, pattern_context *pc)
compiler_pattern_sequence(struct compiler *c, pattern_ty p, pattern_context *pc)
{
assert(p->kind == List_kind || p->kind == Tuple_kind);
asdl_expr_seq *values = (p->kind == Tuple_kind) ? p->v.Tuple.elts
: p->v.List.elts;
Py_ssize_t size = asdl_seq_LEN(values);
assert(p->kind == MatchSequence_kind);
asdl_pattern_seq *patterns = p->v.MatchSequence.patterns;
Py_ssize_t size = asdl_seq_LEN(patterns);
Py_ssize_t star = -1;
int only_wildcard = 1;
int star_wildcard = 0;
// Find a starred name, if it exists. There may be at most one:
for (Py_ssize_t i = 0; i < size; i++) {
expr_ty value = asdl_seq_GET(values, i);
if (value->kind == Starred_kind) {
value = value->v.Starred.value;
pattern_ty pattern = asdl_seq_GET(patterns, i);
if (pattern->kind == MatchStar_kind) {
if (star >= 0) {
const char *e = "multiple starred names in sequence pattern";
return compiler_error(c, e);
}
star_wildcard = WILDCARD_CHECK(value);
star_wildcard = WILDCARD_STAR_CHECK(pattern);
only_wildcard &= star_wildcard;
star = i;
continue;
}
only_wildcard &= WILDCARD_CHECK(value);
only_wildcard &= WILDCARD_CHECK(pattern);
}
basicblock *end, *fail_pop_1;
RETURN_IF_FALSE(end = compiler_new_block(c));
@ -6095,10 +6178,10 @@ compiler_pattern_sequence(struct compiler *c, expr_ty p, pattern_context *pc)
ADDOP_LOAD_CONST(c, Py_True);
}
else if (star_wildcard) {
RETURN_IF_FALSE(pattern_helper_sequence_subscr(c, values, star, pc));
RETURN_IF_FALSE(pattern_helper_sequence_subscr(c, patterns, star, pc));
}
else {
RETURN_IF_FALSE(pattern_helper_sequence_unpack(c, values, star, pc));
RETURN_IF_FALSE(pattern_helper_sequence_unpack(c, patterns, star, pc));
}
ADDOP_JUMP(c, JUMP_FORWARD, end);
compiler_use_next_block(c, fail_pop_1);
@ -6108,72 +6191,57 @@ compiler_pattern_sequence(struct compiler *c, expr_ty p, pattern_context *pc)
return 1;
}
static int
compiler_pattern_value(struct compiler *c, expr_ty p, pattern_context *pc)
compiler_pattern_value(struct compiler *c, pattern_ty p, pattern_context *pc)
{
assert(p->kind == Attribute_kind);
assert(p->v.Attribute.ctx == Load);
VISIT(c, expr, p);
assert(p->kind == MatchValue_kind);
expr_ty value = p->v.MatchValue.value;
if (!MATCH_VALUE_EXPR(value)) {
const char *e = "patterns may only match literals and attribute lookups";
return compiler_error(c, e);
}
VISIT(c, expr, value);
ADDOP_COMPARE(c, Eq);
return 1;
}
static int
compiler_pattern_wildcard(struct compiler *c, expr_ty p, pattern_context *pc)
compiler_pattern_constant(struct compiler *c, pattern_ty p, pattern_context *pc)
{
assert(p->kind == Name_kind);
assert(p->v.Name.ctx == Store);
assert(WILDCARD_CHECK(p));
if (!pc->allow_irrefutable) {
// Whoops, can't have a wildcard here!
const char *e = "wildcard makes remaining patterns unreachable";
return compiler_error(c, e);
}
ADDOP(c, POP_TOP);
ADDOP_LOAD_CONST(c, Py_True);
assert(p->kind == MatchSingleton_kind);
ADDOP_LOAD_CONST(c, p->v.MatchSingleton.value);
ADDOP_COMPARE(c, Is);
return 1;
}
static int
compiler_pattern(struct compiler *c, expr_ty p, pattern_context *pc)
compiler_pattern(struct compiler *c, pattern_ty p, pattern_context *pc)
{
SET_LOC(c, p);
switch (p->kind) {
case Attribute_kind:
case MatchValue_kind:
return compiler_pattern_value(c, p, pc);
case BinOp_kind:
// Because we allow "2+2j", things like "2+2" make it this far:
return compiler_error(c, "patterns cannot include operators");
case Call_kind:
return compiler_pattern_class(c, p, pc);
case Constant_kind:
return compiler_pattern_literal(c, p, pc);
case Dict_kind:
return compiler_pattern_mapping(c, p, pc);
case JoinedStr_kind:
// Because we allow strings, f-strings make it this far:
return compiler_error(c, "patterns cannot include f-strings");
case List_kind:
case Tuple_kind:
case MatchSingleton_kind:
return compiler_pattern_constant(c, p, pc);
case MatchSequence_kind:
return compiler_pattern_sequence(c, p, pc);
case MatchMapping_kind:
return compiler_pattern_mapping(c, p, pc);
case MatchClass_kind:
return compiler_pattern_class(c, p, pc);
case MatchStar_kind:
return compiler_pattern_star(c, p, pc);
case MatchAs_kind:
return compiler_pattern_as(c, p, pc);
case MatchOr_kind:
return compiler_pattern_or(c, p, pc);
case Name_kind:
if (WILDCARD_CHECK(p)) {
return compiler_pattern_wildcard(c, p, pc);
}
return compiler_pattern_capture(c, p, pc);
default:
Py_UNREACHABLE();
}
// AST validator shouldn't let this happen, but if it does,
// just fail, don't crash out of the interpreter
const char *e = "invalid match pattern node in AST (kind=%d)";
return compiler_error(c, e, p->kind);
}
static int
compiler_match(struct compiler *c, stmt_ty s)
{
@ -6181,7 +6249,7 @@ compiler_match(struct compiler *c, stmt_ty s)
basicblock *next, *end;
RETURN_IF_FALSE(end = compiler_new_block(c));
Py_ssize_t cases = asdl_seq_LEN(s->v.Match.cases);
assert(cases);
assert(cases > 0);
pattern_context pc;
// We use pc.stores to track:
// - Repeated name assignments in the same pattern.
@ -6235,9 +6303,8 @@ compiler_match(struct compiler *c, stmt_ty s)
return 1;
}
#undef WILDCARD_CHECK
#undef WILDCARD_STAR_CHECK
/* End of the compiler section, beginning of the assembler section */

64
Python/symtable.c
View file

@ -214,6 +214,7 @@ static int symtable_implicit_arg(struct symtable *st, int pos);
static int symtable_visit_annotations(struct symtable *st, arguments_ty, expr_ty);
static int symtable_visit_withitem(struct symtable *st, withitem_ty item);
static int symtable_visit_match_case(struct symtable *st, match_case_ty m);
static int symtable_visit_pattern(struct symtable *st, pattern_ty s);
static identifier top = NULL, lambda = NULL, genexpr = NULL,
@ -246,7 +247,6 @@ symtable_new(void)
goto fail;
st->st_cur = NULL;
st->st_private = NULL;
st->in_pattern = 0;
return st;
fail:
_PySymtable_Free(st);
@ -1676,13 +1676,6 @@ symtable_visit_expr(struct symtable *st, expr_ty e)
VISIT(st, expr, e->v.Slice.step)
break;
case Name_kind:
// Don't make "_" a local when used in a pattern:
if (st->in_pattern &&
e->v.Name.ctx == Store &&
_PyUnicode_EqualToASCIIString(e->v.Name.id, "_"))
{
break;
}
if (!symtable_add_def(st, e->v.Name.id,
e->v.Name.ctx == Load ? USE : DEF_LOCAL))
VISIT_QUIT(st, 0);
@ -1702,12 +1695,55 @@ symtable_visit_expr(struct symtable *st, expr_ty e)
case Tuple_kind:
VISIT_SEQ(st, expr, e->v.Tuple.elts);
break;
}
VISIT_QUIT(st, 1);
}
static int
symtable_visit_pattern(struct symtable *st, pattern_ty p)
{
if (++st->recursion_depth > st->recursion_limit) {
PyErr_SetString(PyExc_RecursionError,
"maximum recursion depth exceeded during compilation");
VISIT_QUIT(st, 0);
}
switch (p->kind) {
case MatchValue_kind:
VISIT(st, expr, p->v.MatchValue.value);
break;
case MatchSingleton_kind:
/* Nothing to do here. */
break;
case MatchSequence_kind:
VISIT_SEQ(st, pattern, p->v.MatchSequence.patterns);
break;
case MatchStar_kind:
if (p->v.MatchStar.name) {
symtable_add_def(st, p->v.MatchStar.name, DEF_LOCAL);
}
break;
case MatchMapping_kind:
VISIT_SEQ(st, expr, p->v.MatchMapping.keys);
VISIT_SEQ(st, pattern, p->v.MatchMapping.patterns);
if (p->v.MatchMapping.rest) {
symtable_add_def(st, p->v.MatchMapping.rest, DEF_LOCAL);
}
break;
case MatchClass_kind:
VISIT(st, expr, p->v.MatchClass.cls);
VISIT_SEQ(st, pattern, p->v.MatchClass.patterns);
VISIT_SEQ(st, pattern, p->v.MatchClass.kwd_patterns);
break;
case MatchAs_kind:
VISIT(st, expr, e->v.MatchAs.pattern);
symtable_add_def(st, e->v.MatchAs.name, DEF_LOCAL);
if (p->v.MatchAs.pattern) {
VISIT(st, pattern, p->v.MatchAs.pattern);
}
if (p->v.MatchAs.name) {
symtable_add_def(st, p->v.MatchAs.name, DEF_LOCAL);
}
break;
case MatchOr_kind:
VISIT_SEQ(st, expr, e->v.MatchOr.patterns);
VISIT_SEQ(st, pattern, p->v.MatchOr.patterns);
break;
}
VISIT_QUIT(st, 1);
@ -1830,11 +1866,7 @@ symtable_visit_withitem(struct symtable *st, withitem_ty item)
static int
symtable_visit_match_case(struct symtable *st, match_case_ty m)
{
assert(!st->in_pattern);
st->in_pattern = 1;
VISIT(st, expr, m->pattern);
assert(st->in_pattern);
st->in_pattern = 0;
VISIT(st, pattern, m->pattern);
if (m->guard) {
VISIT(st, expr, m->guard);
}