Make rustc::infer::error_reporting::{note_and_explain_free_region, note_and_explain_region} free functions.

3 files changed, 164 insertions, 125 deletions

diff --git a/src/librustc/infer/error_reporting/mod.rs b/src/librustc/infer/error_reporting/mod.rs
index e653f645881..5c2bafd5ae8 100644
--- a/src/librustc/infer/error_reporting/mod.rs
+++ b/src/librustc/infer/error_reporting/mod.rs
@@ -79,98 +79,95 @@ pub use need_type_info::TypeAnnotationNeeded;
 
 pub mod nice_region_error;
 
-impl<'tcx> TyCtxt<'tcx> {
-    pub fn note_and_explain_region(
-        self,
-        region_scope_tree: &region::ScopeTree,
-        err: &mut DiagnosticBuilder<'_>,
-        prefix: &str,
-        region: ty::Region<'tcx>,
-        suffix: &str,
-    ) {
-        let (description, span) = match *region {
-            ty::ReScope(scope) => {
-                let new_string;
-                let unknown_scope = || {
-                    format!("{}unknown scope: {:?}{}.  Please report a bug.", prefix, scope, suffix)
-                };
-                let span = scope.span(self, region_scope_tree);
-                let tag = match self.hir().find(scope.hir_id(region_scope_tree)) {
-                    Some(Node::Block(_)) => "block",
-                    Some(Node::Expr(expr)) => match expr.kind {
-                        hir::ExprKind::Call(..) => "call",
-                        hir::ExprKind::MethodCall(..) => "method call",
-                        hir::ExprKind::Match(.., hir::MatchSource::IfLetDesugar { .. }) => "if let",
-                        hir::ExprKind::Match(.., hir::MatchSource::WhileLetDesugar) => "while let",
-                        hir::ExprKind::Match(.., hir::MatchSource::ForLoopDesugar) => "for",
-                        hir::ExprKind::Match(..) => "match",
-                        _ => "expression",
-                    },
-                    Some(Node::Stmt(_)) => "statement",
-                    Some(Node::Item(it)) => item_scope_tag(&it),
-                    Some(Node::TraitItem(it)) => trait_item_scope_tag(&it),
-                    Some(Node::ImplItem(it)) => impl_item_scope_tag(&it),
-                    Some(_) | None => {
-                        err.span_note(span, &unknown_scope());
-                        return;
-                    }
-                };
-                let scope_decorated_tag = match scope.data {
-                    region::ScopeData::Node => tag,
-                    region::ScopeData::CallSite => "scope of call-site for function",
-                    region::ScopeData::Arguments => "scope of function body",
-                    region::ScopeData::Destruction => {
-                        new_string = format!("destruction scope surrounding {}", tag);
-                        &new_string[..]
-                    }
-                    region::ScopeData::Remainder(first_statement_index) => {
-                        new_string = format!(
-                            "block suffix following statement {}",
-                            first_statement_index.index()
-                        );
-                        &new_string[..]
-                    }
-                };
-                explain_span(self, scope_decorated_tag, span)
-            }
+pub(super) fn note_and_explain_region(
+    tcx: TyCtxt<'tcx>,
+    region_scope_tree: &region::ScopeTree,
+    err: &mut DiagnosticBuilder<'_>,
+    prefix: &str,
+    region: ty::Region<'tcx>,
+    suffix: &str,
+) {
+    let (description, span) = match *region {
+        ty::ReScope(scope) => {
+            let new_string;
+            let unknown_scope =
+                || format!("{}unknown scope: {:?}{}.  Please report a bug.", prefix, scope, suffix);
+            let span = scope.span(tcx, region_scope_tree);
+            let tag = match tcx.hir().find(scope.hir_id(region_scope_tree)) {
+                Some(Node::Block(_)) => "block",
+                Some(Node::Expr(expr)) => match expr.kind {
+                    hir::ExprKind::Call(..) => "call",
+                    hir::ExprKind::MethodCall(..) => "method call",
+                    hir::ExprKind::Match(.., hir::MatchSource::IfLetDesugar { .. }) => "if let",
+                    hir::ExprKind::Match(.., hir::MatchSource::WhileLetDesugar) => "while let",
+                    hir::ExprKind::Match(.., hir::MatchSource::ForLoopDesugar) => "for",
+                    hir::ExprKind::Match(..) => "match",
+                    _ => "expression",
+                },
+                Some(Node::Stmt(_)) => "statement",
+                Some(Node::Item(it)) => item_scope_tag(&it),
+                Some(Node::TraitItem(it)) => trait_item_scope_tag(&it),
+                Some(Node::ImplItem(it)) => impl_item_scope_tag(&it),
+                Some(_) | None => {
+                    err.span_note(span, &unknown_scope());
+                    return;
+                }
+            };
+            let scope_decorated_tag = match scope.data {
+                region::ScopeData::Node => tag,
+                region::ScopeData::CallSite => "scope of call-site for function",
+                region::ScopeData::Arguments => "scope of function body",
+                region::ScopeData::Destruction => {
+                    new_string = format!("destruction scope surrounding {}", tag);
+                    &new_string[..]
+                }
+                region::ScopeData::Remainder(first_statement_index) => {
+                    new_string = format!(
+                        "block suffix following statement {}",
+                        first_statement_index.index()
+                    );
+                    &new_string[..]
+                }
+            };
+            explain_span(tcx, scope_decorated_tag, span)
+        }
 
-            ty::ReEarlyBound(_) | ty::ReFree(_) | ty::ReStatic => {
-                msg_span_from_free_region(self, region)
-            }
+        ty::ReEarlyBound(_) | ty::ReFree(_) | ty::ReStatic => {
+            msg_span_from_free_region(tcx, region)
+        }
 
-            ty::ReEmpty => ("the empty lifetime".to_owned(), None),
+        ty::ReEmpty => ("the empty lifetime".to_owned(), None),
 
-            ty::RePlaceholder(_) => (format!("any other region"), None),
+        ty::RePlaceholder(_) => (format!("any other region"), None),
 
-            // FIXME(#13998) RePlaceholder should probably print like
-            // ReFree rather than dumping Debug output on the user.
-            //
-            // We shouldn't really be having unification failures with ReVar
-            // and ReLateBound though.
-            ty::ReVar(_) | ty::ReLateBound(..) | ty::ReErased => {
-                (format!("lifetime {:?}", region), None)
-            }
+        // FIXME(#13998) RePlaceholder should probably print like
+        // ReFree rather than dumping Debug output on the user.
+        //
+        // We shouldn't really be having unification failures with ReVar
+        // and ReLateBound though.
+        ty::ReVar(_) | ty::ReLateBound(..) | ty::ReErased => {
+            (format!("lifetime {:?}", region), None)
+        }
 
-            // We shouldn't encounter an error message with ReClosureBound.
-            ty::ReClosureBound(..) => {
-                bug!("encountered unexpected ReClosureBound: {:?}", region,);
-            }
-        };
+        // We shouldn't encounter an error message with ReClosureBound.
+        ty::ReClosureBound(..) => {
+            bug!("encountered unexpected ReClosureBound: {:?}", region,);
+        }
+    };
 
-        emit_msg_span(err, prefix, description, span, suffix);
-    }
+    emit_msg_span(err, prefix, description, span, suffix);
+}
 
-    pub fn note_and_explain_free_region(
-        self,
-        err: &mut DiagnosticBuilder<'_>,
-        prefix: &str,
-        region: ty::Region<'tcx>,
-        suffix: &str,
-    ) {
-        let (description, span) = msg_span_from_free_region(self, region);
+pub(super) fn note_and_explain_free_region(
+    tcx: TyCtxt<'tcx>,
+    err: &mut DiagnosticBuilder<'_>,
+    prefix: &str,
+    region: ty::Region<'tcx>,
+    suffix: &str,
+) {
+    let (description, span) = msg_span_from_free_region(tcx, region);
 
-        emit_msg_span(err, prefix, description, span, suffix);
-    }
+    emit_msg_span(err, prefix, description, span, suffix);
 }
 
 fn msg_span_from_free_region(
@@ -1719,7 +1716,8 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                     "consider adding an explicit lifetime bound for `{}`",
                     bound_kind
                 ));
-                self.tcx.note_and_explain_region(
+                note_and_explain_region(
+                    self.tcx,
                     region_scope_tree,
                     &mut err,
                     &format!("{} must be valid for ", labeled_user_string),
@@ -1747,7 +1745,8 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     ) {
         let mut err = self.report_inference_failure(var_origin);
 
-        self.tcx.note_and_explain_region(
+        note_and_explain_region(
+            self.tcx,
             region_scope_tree,
             &mut err,
             "first, the lifetime cannot outlive ",
@@ -1771,7 +1770,8 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                     (self.values_str(&sup_trace.values), self.values_str(&sub_trace.values))
                 {
                     if sub_expected == sup_expected && sub_found == sup_found {
-                        self.tcx.note_and_explain_region(
+                        note_and_explain_region(
+                            self.tcx,
                             region_scope_tree,
                             &mut err,
                             "...but the lifetime must also be valid for ",
@@ -1794,7 +1794,8 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
 
         self.note_region_origin(&mut err, &sup_origin);
 
-        self.tcx.note_and_explain_region(
+        note_and_explain_region(
+            self.tcx,
             region_scope_tree,
             &mut err,
             "but, the lifetime must be valid for ",
diff --git a/src/librustc/infer/error_reporting/note.rs b/src/librustc/infer/error_reporting/note.rs
index 979bcca619c..7919274c373 100644
--- a/src/librustc/infer/error_reporting/note.rs
+++ b/src/librustc/infer/error_reporting/note.rs
@@ -1,3 +1,4 @@
+use crate::infer::error_reporting::note_and_explain_region;
 use crate::infer::{self, InferCtxt, SubregionOrigin};
 use crate::middle::region;
 use crate::ty::error::TypeError;
@@ -167,8 +168,9 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             infer::Subtype(box trace) => {
                 let terr = TypeError::RegionsDoesNotOutlive(sup, sub);
                 let mut err = self.report_and_explain_type_error(trace, &terr);
-                self.tcx.note_and_explain_region(region_scope_tree, &mut err, "", sup, "...");
-                self.tcx.note_and_explain_region(
+                note_and_explain_region(self.tcx, region_scope_tree, &mut err, "", sup, "...");
+                note_and_explain_region(
+                    self.tcx,
                     region_scope_tree,
                     &mut err,
                     "...does not necessarily outlive ",
@@ -185,14 +187,16 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                     "lifetime of reference outlives lifetime of \
                                                 borrowed content..."
                 );
-                self.tcx.note_and_explain_region(
+                note_and_explain_region(
+                    self.tcx,
                     region_scope_tree,
                     &mut err,
                     "...the reference is valid for ",
                     sub,
                     "...",
                 );
-                self.tcx.note_and_explain_region(
+                note_and_explain_region(
+                    self.tcx,
                     region_scope_tree,
                     &mut err,
                     "...but the borrowed content is only valid for ",
@@ -211,14 +215,16 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                                                 of captured variable `{}`...",
                     var_name
                 );
-                self.tcx.note_and_explain_region(
+                note_and_explain_region(
+                    self.tcx,
                     region_scope_tree,
                     &mut err,
                     "...the borrowed pointer is valid for ",
                     sub,
                     "...",
                 );
-                self.tcx.note_and_explain_region(
+                note_and_explain_region(
+                    self.tcx,
                     region_scope_tree,
                     &mut err,
                     &format!("...but `{}` is only valid for ", var_name),
@@ -230,14 +236,16 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             infer::InfStackClosure(span) => {
                 let mut err =
                     struct_span_err!(self.tcx.sess, span, E0314, "closure outlives stack frame");
-                self.tcx.note_and_explain_region(
+                note_and_explain_region(
+                    self.tcx,
                     region_scope_tree,
                     &mut err,
                     "...the closure must be valid for ",
                     sub,
                     "...",
                 );
-                self.tcx.note_and_explain_region(
+                note_and_explain_region(
+                    self.tcx,
                     region_scope_tree,
                     &mut err,
                     "...but the closure's stack frame is only valid \
@@ -254,7 +262,8 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                     E0315,
                     "cannot invoke closure outside of its lifetime"
                 );
-                self.tcx.note_and_explain_region(
+                note_and_explain_region(
+                    self.tcx,
                     region_scope_tree,
                     &mut err,
                     "the closure is only valid for ",
@@ -270,7 +279,8 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                     E0473,
                     "dereference of reference outside its lifetime"
                 );
-                self.tcx.note_and_explain_region(
+                note_and_explain_region(
+                    self.tcx,
                     region_scope_tree,
                     &mut err,
                     "the reference is only valid for ",
@@ -288,14 +298,16 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                                                 enclosing closure",
                     self.tcx.hir().name(id)
                 );
-                self.tcx.note_and_explain_region(
+                note_and_explain_region(
+                    self.tcx,
                     region_scope_tree,
                     &mut err,
                     "captured variable is valid for ",
                     sup,
                     "",
                 );
-                self.tcx.note_and_explain_region(
+                note_and_explain_region(
+                    self.tcx,
                     region_scope_tree,
                     &mut err,
                     "closure is valid for ",
@@ -311,7 +323,8 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                     E0475,
                     "index of slice outside its lifetime"
                 );
-                self.tcx.note_and_explain_region(
+                note_and_explain_region(
+                    self.tcx,
                     region_scope_tree,
                     &mut err,
                     "the slice is only valid for ",
@@ -328,14 +341,16 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                     "lifetime of the source pointer does not outlive \
                                                 lifetime bound of the object type"
                 );
-                self.tcx.note_and_explain_region(
+                note_and_explain_region(
+                    self.tcx,
                     region_scope_tree,
                     &mut err,
                     "object type is valid for ",
                     sub,
                     "",
                 );
-                self.tcx.note_and_explain_region(
+                note_and_explain_region(
+                    self.tcx,
                     region_scope_tree,
                     &mut err,
                     "source pointer is only valid for ",
@@ -354,14 +369,16 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                     self.ty_to_string(ty)
                 );
                 match *sub {
-                    ty::ReStatic => self.tcx.note_and_explain_region(
+                    ty::ReStatic => note_and_explain_region(
+                        self.tcx,
                         region_scope_tree,
                         &mut err,
                         "type must satisfy ",
                         sub,
                         "",
                     ),
-                    _ => self.tcx.note_and_explain_region(
+                    _ => note_and_explain_region(
+                        self.tcx,
                         region_scope_tree,
                         &mut err,
                         "type must outlive ",
@@ -374,14 +391,16 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             infer::RelateRegionParamBound(span) => {
                 let mut err =
                     struct_span_err!(self.tcx.sess, span, E0478, "lifetime bound not satisfied");
-                self.tcx.note_and_explain_region(
+                note_and_explain_region(
+                    self.tcx,
                     region_scope_tree,
                     &mut err,
                     "lifetime parameter instantiated with ",
                     sup,
                     "",
                 );
-                self.tcx.note_and_explain_region(
+                note_and_explain_region(
+                    self.tcx,
                     region_scope_tree,
                     &mut err,
                     "but lifetime parameter must outlive ",
@@ -399,7 +418,8 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                                                 parameter) is not valid at this point",
                     self.ty_to_string(ty)
                 );
-                self.tcx.note_and_explain_region(
+                note_and_explain_region(
+                    self.tcx,
                     region_scope_tree,
                     &mut err,
                     "type must outlive ",
@@ -416,7 +436,8 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                     "lifetime of method receiver does not outlive the \
                                                 method call"
                 );
-                self.tcx.note_and_explain_region(
+                note_and_explain_region(
+                    self.tcx,
                     region_scope_tree,
                     &mut err,
                     "the receiver is only valid for ",
@@ -433,7 +454,8 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                     "lifetime of function argument does not outlive \
                                                 the function call"
                 );
-                self.tcx.note_and_explain_region(
+                note_and_explain_region(
+                    self.tcx,
                     region_scope_tree,
                     &mut err,
                     "the function argument is only valid for ",
@@ -450,7 +472,8 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                     "lifetime of return value does not outlive the \
                                                 function call"
                 );
-                self.tcx.note_and_explain_region(
+                note_and_explain_region(
+                    self.tcx,
                     region_scope_tree,
                     &mut err,
                     "the return value is only valid for ",
@@ -467,7 +490,8 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                     "lifetime of operand does not outlive the \
                                                 operation"
                 );
-                self.tcx.note_and_explain_region(
+                note_and_explain_region(
+                    self.tcx,
                     region_scope_tree,
                     &mut err,
                     "the operand is only valid for ",
@@ -483,7 +507,8 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                     E0484,
                     "reference is not valid at the time of borrow"
                 );
-                self.tcx.note_and_explain_region(
+                note_and_explain_region(
+                    self.tcx,
                     region_scope_tree,
                     &mut err,
                     "the borrow is only valid for ",
@@ -500,7 +525,8 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                     "automatically reference is not valid at the time \
                                                 of borrow"
                 );
-                self.tcx.note_and_explain_region(
+                note_and_explain_region(
+                    self.tcx,
                     region_scope_tree,
                     &mut err,
                     "the automatic borrow is only valid for ",
@@ -518,7 +544,8 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                                                 not valid during the expression: `{}`",
                     self.ty_to_string(t)
                 );
-                self.tcx.note_and_explain_region(
+                note_and_explain_region(
+                    self.tcx,
                     region_scope_tree,
                     &mut err,
                     "type is only valid for ",
@@ -536,14 +563,16 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                                                 called while references are dead"
                 );
                 // FIXME (22171): terms "super/subregion" are suboptimal
-                self.tcx.note_and_explain_region(
+                note_and_explain_region(
+                    self.tcx,
                     region_scope_tree,
                     &mut err,
                     "superregion: ",
                     sup,
                     "",
                 );
-                self.tcx.note_and_explain_region(
+                note_and_explain_region(
+                    self.tcx,
                     region_scope_tree,
                     &mut err,
                     "subregion: ",
@@ -560,7 +589,8 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                     "lifetime of variable does not enclose its \
                                                 declaration"
                 );
-                self.tcx.note_and_explain_region(
+                note_and_explain_region(
+                    self.tcx,
                     region_scope_tree,
                     &mut err,
                     "the variable is only valid for ",
@@ -576,7 +606,8 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                     E0489,
                     "type/lifetime parameter not in scope here"
                 );
-                self.tcx.note_and_explain_region(
+                note_and_explain_region(
+                    self.tcx,
                     region_scope_tree,
                     &mut err,
                     "the parameter is only valid for ",
@@ -593,14 +624,16 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                     "a value of type `{}` is borrowed for too long",
                     self.ty_to_string(ty)
                 );
-                self.tcx.note_and_explain_region(
+                note_and_explain_region(
+                    self.tcx,
                     region_scope_tree,
                     &mut err,
                     "the type is valid for ",
                     sub,
                     "",
                 );
-                self.tcx.note_and_explain_region(
+                note_and_explain_region(
+                    self.tcx,
                     region_scope_tree,
                     &mut err,
                     "but the borrow lasts for ",
@@ -618,14 +651,16 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                                                 than the data it references",
                     self.ty_to_string(ty)
                 );
-                self.tcx.note_and_explain_region(
+                note_and_explain_region(
+                    self.tcx,
                     region_scope_tree,
                     &mut err,
                     "the pointer is valid for ",
                     sub,
                     "",
                 );
-                self.tcx.note_and_explain_region(
+                note_and_explain_region(
+                    self.tcx,
                     region_scope_tree,
                     &mut err,
                     "but the referenced data is only valid for ",
diff --git a/src/librustc/infer/opaque_types/mod.rs b/src/librustc/infer/opaque_types/mod.rs
index e9b1ebbd3f6..834b8e8e72e 100644
--- a/src/librustc/infer/opaque_types/mod.rs
+++ b/src/librustc/infer/opaque_types/mod.rs
@@ -1,3 +1,4 @@
+use crate::infer::error_reporting::{note_and_explain_free_region, note_and_explain_region};
 use crate::infer::outlives::free_region_map::FreeRegionRelations;
 use crate::infer::{self, InferCtxt, InferOk, TypeVariableOrigin, TypeVariableOriginKind};
 use crate::middle::region;
@@ -624,7 +625,8 @@ pub fn unexpected_hidden_region_diagnostic(
         //
         // (*) if not, the `tainted_by_errors` flag would be set to
         // true in any case, so we wouldn't be here at all.
-        tcx.note_and_explain_free_region(
+        note_and_explain_free_region(
+            tcx,
             &mut err,
             &format!("hidden type `{}` captures ", hidden_ty),
             hidden_region,
@@ -649,7 +651,8 @@ pub fn unexpected_hidden_region_diagnostic(
             // If the `region_scope_tree` is available, this is being
             // invoked from the "region inferencer error". We can at
             // least report a really cryptic error for now.
-            tcx.note_and_explain_region(
+            note_and_explain_region(
+                tcx,
                 region_scope_tree,
                 &mut err,
                 &format!("hidden type `{}` captures ", hidden_ty),