Clean up check_loans.
Refactor a number of functions in check_loans to take node IDs and spans rather than taking expressions directly. Also rename some variables to make them less ambiguous. This is the first step towards using ExprUseVisitor in check_loans, as now some of the interfaces more closely match those used in ExprUseVisitor.
This commit is contained in:
Cameron Zwarich
parent
071e22ed89
commit
d123188b20
1 changed files with 48 additions and 37 deletions
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@ -385,24 +385,34 @@ impl<'a> CheckLoanCtxt<'a> {
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});
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}
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pub fn check_assignment(&self, expr: &ast::Expr) {
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pub fn check_assignment_expr(&self, expr: &ast::Expr) {
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let assignment_id = expr.id;
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let assignment_span = expr.span;
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// We don't use cat_expr() here because we don't want to treat
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// auto-ref'd parameters in overloaded operators as rvalues.
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let cmt = match self.bccx.tcx.adjustments.borrow().find(&expr.id) {
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let assignee_cmt = match self.bccx.tcx.adjustments.borrow().find(&assignment_id) {
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None => self.bccx.cat_expr_unadjusted(expr),
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Some(adj) => self.bccx.cat_expr_autoderefd(expr, adj)
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};
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debug!("check_assignment(cmt={})", cmt.repr(self.tcx()));
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self.check_assignment(assignment_id, assignment_span, assignee_cmt);
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}
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fn check_assignment(&self,
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assignment_id: ast::NodeId,
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assignment_span: Span,
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assignee_cmt: mc::cmt) {
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debug!("check_assignment(assignee_cmt={})", assignee_cmt.repr(self.tcx()));
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// Mutable values can be assigned, as long as they obey loans
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// and aliasing restrictions:
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if cmt.mutbl.is_mutable() {
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if check_for_aliasable_mutable_writes(self, expr, cmt.clone()) {
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if assignee_cmt.mutbl.is_mutable() {
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if check_for_aliasable_mutable_writes(self, assignment_span, assignee_cmt.clone()) {
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if check_for_assignment_to_restricted_or_frozen_location(
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self, expr, cmt.clone()) {
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self, assignment_id, assignment_span, assignee_cmt.clone()) {
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// Safe, but record for lint pass later:
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mark_variable_as_used_mut(self, cmt);
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mark_variable_as_used_mut(self, assignee_cmt);
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}
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}
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return;
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@ -410,12 +420,12 @@ impl<'a> CheckLoanCtxt<'a> {
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// For immutable local variables, assignments are legal
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// if they cannot already have been assigned
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if self.is_local_variable(cmt.clone()) {
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assert!(cmt.mutbl.is_immutable()); // no "const" locals
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let lp = opt_loan_path(&cmt).unwrap();
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self.move_data.each_assignment_of(expr.id, &lp, |assign| {
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if self.is_local_variable(assignee_cmt.clone()) {
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assert!(assignee_cmt.mutbl.is_immutable()); // no "const" locals
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let lp = opt_loan_path(&assignee_cmt).unwrap();
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self.move_data.each_assignment_of(assignment_id, &lp, |assign| {
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self.bccx.report_reassigned_immutable_variable(
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expr.span,
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assignment_span,
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&*lp,
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assign);
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false
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@ -424,21 +434,21 @@ impl<'a> CheckLoanCtxt<'a> {
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}
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// Otherwise, just a plain error.
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match opt_loan_path(&cmt) {
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match opt_loan_path(&assignee_cmt) {
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Some(lp) => {
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self.bccx.span_err(
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expr.span,
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assignment_span,
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format!("cannot assign to {} {} `{}`",
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cmt.mutbl.to_user_str(),
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self.bccx.cmt_to_str(&*cmt),
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assignee_cmt.mutbl.to_user_str(),
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self.bccx.cmt_to_str(&*assignee_cmt),
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self.bccx.loan_path_to_str(&*lp)).as_slice());
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}
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None => {
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self.bccx.span_err(
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expr.span,
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assignment_span,
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format!("cannot assign to {} {}",
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cmt.mutbl.to_user_str(),
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self.bccx.cmt_to_str(&*cmt)).as_slice());
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assignee_cmt.mutbl.to_user_str(),
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self.bccx.cmt_to_str(&*assignee_cmt)).as_slice());
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}
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}
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return;
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@ -495,7 +505,7 @@ impl<'a> CheckLoanCtxt<'a> {
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}
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fn check_for_aliasable_mutable_writes(this: &CheckLoanCtxt,
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expr: &ast::Expr,
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span: Span,
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cmt: mc::cmt) -> bool {
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//! Safety checks related to writes to aliasable, mutable locations
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@ -506,7 +516,7 @@ impl<'a> CheckLoanCtxt<'a> {
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mc::cat_deref(ref b, _, mc::BorrowedPtr(ty::MutBorrow, _)) => {
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// Statically prohibit writes to `&mut` when aliasable
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check_for_aliasability_violation(this, expr, b.clone());
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check_for_aliasability_violation(this, span, b.clone());
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}
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_ => {}
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@ -516,7 +526,7 @@ impl<'a> CheckLoanCtxt<'a> {
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}
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fn check_for_aliasability_violation(this: &CheckLoanCtxt,
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expr: &ast::Expr,
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span: Span,
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cmt: mc::cmt)
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-> bool {
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match cmt.freely_aliasable(this.tcx()) {
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@ -528,7 +538,7 @@ impl<'a> CheckLoanCtxt<'a> {
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}
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Some(cause) => {
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this.bccx.report_aliasability_violation(
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expr.span,
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span,
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MutabilityViolation,
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cause);
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return false;
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@ -538,13 +548,14 @@ impl<'a> CheckLoanCtxt<'a> {
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fn check_for_assignment_to_restricted_or_frozen_location(
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this: &CheckLoanCtxt,
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expr: &ast::Expr,
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cmt: mc::cmt) -> bool
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assignment_id: ast::NodeId,
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assignment_span: Span,
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assignee_cmt: mc::cmt) -> bool
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{
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//! Check for assignments that violate the terms of an
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//! outstanding loan.
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let loan_path = match opt_loan_path(&cmt) {
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let loan_path = match opt_loan_path(&assignee_cmt) {
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Some(lp) => lp,
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None => { return true; /* no loan path, can't be any loans */ }
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};
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@ -579,11 +590,11 @@ impl<'a> CheckLoanCtxt<'a> {
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// `RESTR_MUTATE` restriction whenever the contents of an
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// owned pointer are borrowed, and hence while `v[*]` is not
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// restricted from being written, `v` is.
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let cont = this.each_in_scope_restriction(expr.id,
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let cont = this.each_in_scope_restriction(assignment_id,
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&*loan_path,
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|loan, restr| {
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if restr.set.intersects(RESTR_MUTATE) {
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this.report_illegal_mutation(expr, &*loan_path, loan);
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this.report_illegal_mutation(assignment_span, &*loan_path, loan);
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false
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} else {
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true
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@ -656,9 +667,9 @@ impl<'a> CheckLoanCtxt<'a> {
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};
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// Check for a non-const loan of `loan_path`
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let cont = this.each_in_scope_loan(expr.id, |loan| {
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let cont = this.each_in_scope_loan(assignment_id, |loan| {
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if loan.loan_path == loan_path {
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this.report_illegal_mutation(expr, &*full_loan_path, loan);
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this.report_illegal_mutation(assignment_span, &*full_loan_path, loan);
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false
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} else {
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true
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@ -671,11 +682,11 @@ impl<'a> CheckLoanCtxt<'a> {
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}
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pub fn report_illegal_mutation(&self,
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expr: &ast::Expr,
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span: Span,
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loan_path: &LoanPath,
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loan: &Loan) {
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self.bccx.span_err(
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expr.span,
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span,
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format!("cannot assign to `{}` because it is borrowed",
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self.bccx.loan_path_to_str(loan_path)).as_slice());
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self.bccx.span_note(
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@ -733,7 +744,7 @@ impl<'a> CheckLoanCtxt<'a> {
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match freevar_mode {
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freevars::CaptureByRef => { }
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freevars::CaptureByValue => {
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check_by_move_capture(self, closure_id, freevar, &*var_path);
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check_by_move_capture(self, closure_id, freevar.span, &*var_path);
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}
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}
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}
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@ -742,14 +753,14 @@ impl<'a> CheckLoanCtxt<'a> {
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fn check_by_move_capture(this: &CheckLoanCtxt,
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closure_id: ast::NodeId,
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freevar: &freevars::freevar_entry,
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freevar_span: Span,
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move_path: &LoanPath) {
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let move_err = this.analyze_move_out_from(closure_id, move_path);
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match move_err {
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MoveOk => {}
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MoveWhileBorrowed(loan_path, loan_span) => {
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this.bccx.span_err(
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freevar.span,
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freevar_span,
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format!("cannot move `{}` into closure \
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because it is borrowed",
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this.bccx.loan_path_to_str(
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@ -841,7 +852,7 @@ fn check_loans_in_expr<'a>(this: &mut CheckLoanCtxt<'a>,
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}
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ast::ExprAssign(dest, _) |
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ast::ExprAssignOp(_, dest, _) => {
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this.check_assignment(dest);
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this.check_assignment_expr(dest);
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}
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ast::ExprCall(f, ref args) => {
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this.check_call(expr, Some(f), f.span, args.as_slice());
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@ -859,7 +870,7 @@ fn check_loans_in_expr<'a>(this: &mut CheckLoanCtxt<'a>,
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}
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ast::ExprInlineAsm(ref ia) => {
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for &(_, out) in ia.outputs.iter() {
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this.check_assignment(out);
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this.check_assignment_expr(out);
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}
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}
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_ => {}
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