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use super::{
Arm, Block, Expr, ExprKind, Guard, InlineAsmOperand, Pat, PatKind, Stmt, StmtKind, Thir,
};
pub trait Visitor<'a, 'tcx: 'a>: Sized {
fn thir(&self) -> &'a Thir<'tcx>;
fn visit_expr(&mut self, expr: &Expr<'tcx>) {
walk_expr(self, expr);
}
fn visit_stmt(&mut self, stmt: &Stmt<'tcx>) {
walk_stmt(self, stmt);
}
fn visit_block(&mut self, block: &Block) {
walk_block(self, block);
}
fn visit_arm(&mut self, arm: &Arm<'tcx>) {
walk_arm(self, arm);
}
fn visit_pat(&mut self, pat: &Pat<'tcx>) {
walk_pat(self, pat);
}
// Note: We don't have visitors for `ty::Const` and `mir::ConstantKind`
// (even though these types occur in THIR) for consistency and to reduce confusion,
// since the lazy creation of constants during thir construction causes most
// 'constants' to not be of type `ty::Const` or `mir::ConstantKind` at that
// stage (they are mostly still identified by `DefId` or `hir::Lit`, see
// the variants `Literal`, `NonHirLiteral` and `NamedConst` in `thir::ExprKind`).
// You have to manually visit `ty::Const` and `mir::ConstantKind` through the
// other `visit*` functions.
}
pub fn walk_expr<'a, 'tcx: 'a, V: Visitor<'a, 'tcx>>(visitor: &mut V, expr: &Expr<'tcx>) {
use ExprKind::*;
match expr.kind {
Scope { value, region_scope: _, lint_level: _ } => {
visitor.visit_expr(&visitor.thir()[value])
}
Box { value } => visitor.visit_expr(&visitor.thir()[value]),
If { cond, then, else_opt, if_then_scope: _ } => {
visitor.visit_expr(&visitor.thir()[cond]);
visitor.visit_expr(&visitor.thir()[then]);
if let Some(else_expr) = else_opt {
visitor.visit_expr(&visitor.thir()[else_expr]);
}
}
Call { fun, ref args, ty: _, from_hir_call: _, fn_span: _ } => {
visitor.visit_expr(&visitor.thir()[fun]);
for &arg in &**args {
visitor.visit_expr(&visitor.thir()[arg]);
}
}
Deref { arg } => visitor.visit_expr(&visitor.thir()[arg]),
Binary { lhs, rhs, op: _ } | LogicalOp { lhs, rhs, op: _ } => {
visitor.visit_expr(&visitor.thir()[lhs]);
visitor.visit_expr(&visitor.thir()[rhs]);
}
Unary { arg, op: _ } => visitor.visit_expr(&visitor.thir()[arg]),
Cast { source } => visitor.visit_expr(&visitor.thir()[source]),
Use { source } => visitor.visit_expr(&visitor.thir()[source]),
NeverToAny { source } => visitor.visit_expr(&visitor.thir()[source]),
Pointer { source, cast: _ } => visitor.visit_expr(&visitor.thir()[source]),
Let { expr, .. } => {
visitor.visit_expr(&visitor.thir()[expr]);
}
Loop { body } => visitor.visit_expr(&visitor.thir()[body]),
Match { scrutinee, ref arms } => {
visitor.visit_expr(&visitor.thir()[scrutinee]);
for &arm in &**arms {
visitor.visit_arm(&visitor.thir()[arm]);
}
}
Block { ref body } => visitor.visit_block(body),
Assign { lhs, rhs } | AssignOp { lhs, rhs, op: _ } => {
visitor.visit_expr(&visitor.thir()[lhs]);
visitor.visit_expr(&visitor.thir()[rhs]);
}
Field { lhs, variant_index: _, name: _ } => visitor.visit_expr(&visitor.thir()[lhs]),
Index { lhs, index } => {
visitor.visit_expr(&visitor.thir()[lhs]);
visitor.visit_expr(&visitor.thir()[index]);
}
VarRef { id: _ } | UpvarRef { closure_def_id: _, var_hir_id: _ } => {}
Borrow { arg, borrow_kind: _ } => visitor.visit_expr(&visitor.thir()[arg]),
AddressOf { arg, mutability: _ } => visitor.visit_expr(&visitor.thir()[arg]),
Break { value, label: _ } => {
if let Some(value) = value {
visitor.visit_expr(&visitor.thir()[value])
}
}
Continue { label: _ } => {}
Return { value } => {
if let Some(value) = value {
visitor.visit_expr(&visitor.thir()[value])
}
}
ConstBlock { did: _, substs: _ } => {}
Repeat { value, count: _ } => {
visitor.visit_expr(&visitor.thir()[value]);
}
Array { ref fields } | Tuple { ref fields } => {
for &field in &**fields {
visitor.visit_expr(&visitor.thir()[field]);
}
}
Adt(box crate::thir::Adt {
ref fields,
ref base,
adt_def: _,
variant_index: _,
substs: _,
user_ty: _,
}) => {
for field in &**fields {
visitor.visit_expr(&visitor.thir()[field.expr]);
}
if let Some(base) = base {
visitor.visit_expr(&visitor.thir()[base.base]);
}
}
PlaceTypeAscription { source, user_ty: _ } | ValueTypeAscription { source, user_ty: _ } => {
visitor.visit_expr(&visitor.thir()[source])
}
Closure { closure_id: _, substs: _, upvars: _, movability: _, fake_reads: _ } => {}
Literal { lit: _, neg: _ } => {}
NonHirLiteral { lit: _, user_ty: _ } => {}
ZstLiteral { user_ty: _ } => {}
NamedConst { def_id: _, substs: _, user_ty: _ } => {}
ConstParam { param: _, def_id: _ } => {}
StaticRef { alloc_id: _, ty: _, def_id: _ } => {}
InlineAsm { ref operands, template: _, options: _, line_spans: _ } => {
for op in &**operands {
use InlineAsmOperand::*;
match op {
In { expr, reg: _ }
| Out { expr: Some(expr), reg: _, late: _ }
| InOut { expr, reg: _, late: _ } => visitor.visit_expr(&visitor.thir()[*expr]),
SplitInOut { in_expr, out_expr, reg: _, late: _ } => {
visitor.visit_expr(&visitor.thir()[*in_expr]);
if let Some(out_expr) = out_expr {
visitor.visit_expr(&visitor.thir()[*out_expr]);
}
}
Out { expr: None, reg: _, late: _ }
| Const { value: _, span: _ }
| SymFn { value: _, span: _ }
| SymStatic { def_id: _ } => {}
}
}
}
ThreadLocalRef(_) => {}
Yield { value } => visitor.visit_expr(&visitor.thir()[value]),
}
}
pub fn walk_stmt<'a, 'tcx: 'a, V: Visitor<'a, 'tcx>>(visitor: &mut V, stmt: &Stmt<'tcx>) {
match &stmt.kind {
StmtKind::Expr { expr, scope: _ } => visitor.visit_expr(&visitor.thir()[*expr]),
StmtKind::Let {
initializer,
remainder_scope: _,
init_scope: _,
ref pattern,
lint_level: _,
else_block,
} => {
if let Some(init) = initializer {
visitor.visit_expr(&visitor.thir()[*init]);
}
visitor.visit_pat(pattern);
if let Some(block) = else_block {
visitor.visit_block(block)
}
}
}
}
pub fn walk_block<'a, 'tcx: 'a, V: Visitor<'a, 'tcx>>(visitor: &mut V, block: &Block) {
for &stmt in &*block.stmts {
visitor.visit_stmt(&visitor.thir()[stmt]);
}
if let Some(expr) = block.expr {
visitor.visit_expr(&visitor.thir()[expr]);
}
}
pub fn walk_arm<'a, 'tcx: 'a, V: Visitor<'a, 'tcx>>(visitor: &mut V, arm: &Arm<'tcx>) {
match arm.guard {
Some(Guard::If(expr)) => visitor.visit_expr(&visitor.thir()[expr]),
Some(Guard::IfLet(ref pat, expr)) => {
visitor.visit_pat(pat);
visitor.visit_expr(&visitor.thir()[expr]);
}
None => {}
}
visitor.visit_pat(&arm.pattern);
visitor.visit_expr(&visitor.thir()[arm.body]);
}
pub fn walk_pat<'a, 'tcx: 'a, V: Visitor<'a, 'tcx>>(visitor: &mut V, pat: &Pat<'tcx>) {
use PatKind::*;
match pat.kind.as_ref() {
AscribeUserType { subpattern, ascription: _ }
| Deref { subpattern }
| Binding {
subpattern: Some(subpattern),
mutability: _,
mode: _,
var: _,
ty: _,
is_primary: _,
name: _,
} => visitor.visit_pat(&subpattern),
Binding { .. } | Wild => {}
Variant { subpatterns, adt_def: _, substs: _, variant_index: _ } | Leaf { subpatterns } => {
for subpattern in subpatterns {
visitor.visit_pat(&subpattern.pattern);
}
}
Constant { value: _ } => {}
Range(_) => {}
Slice { prefix, slice, suffix } | Array { prefix, slice, suffix } => {
for subpattern in prefix {
visitor.visit_pat(&subpattern);
}
if let Some(pat) = slice {
visitor.visit_pat(pat);
}
for subpattern in suffix {
visitor.visit_pat(&subpattern);
}
}
Or { pats } => {
for pat in pats {
visitor.visit_pat(&pat);
}
}
};
}
|
