Auto merge of #32562 - ben0x539:bug-macro, r=nikomatsakis

librustc: Add bug!(), bug_span!() macros as unified entry points for internal compiler errors

The macros pass `file!()`, `line!()` and `format_args!(...)` on to a cold, never-inlined function, ultimately calling `session::{span_,}bug_fmt` via the tcx in tls or, failing that, panicking directly.

cc @eddyb
r? @nikomatsakis

src/librustc/cfg/construct.rs

@@ -583,13 +583,11 @@ impl<'a, 'tcx> CFGBuilder<'a, 'tcx> {
                         return *l;
                     }
                 }
-                self.tcx.sess.span_bug(expr.span,
-                    &format!("no loop scope for id {}", loop_id));
+                span_bug!(expr.span, "no loop scope for id {}", loop_id);
             }
 
             r => {
-                self.tcx.sess.span_bug(expr.span,
-                    &format!("bad entry `{:?}` in def_map for label", r));
+                span_bug!(expr.span, "bad entry `{:?}` in def_map for label", r);
             }
         }
     }

src/librustc/dep_graph/edges.rs

@@ -122,7 +122,7 @@ impl DepGraphEdges {
     {
         match self.current_node() {
             Some(open_node) => self.add_edge_from_open_node(open_node, op),
-            None => panic!("no current node, cannot add edge into dependency graph")
+            None => bug!("no current node, cannot add edge into dependency graph")
         }
     }
 

src/librustc/dep_graph/thread.rs

@@ -148,7 +148,7 @@ impl DepGraphThreadData {
 
     // Outline this too.
     fn invalid_message(&self, string: &str) {
-        panic!("{}; see src/librustc/dep_graph/README.md for more information", string)
+        bug!("{}; see src/librustc/dep_graph/README.md for more information", string)
     }
 }
 

src/librustc/front/map/blocks.rs

@@ -231,21 +231,21 @@ impl<'a> FnLikeNode<'a> {
                         span: i.span,
                         attrs: &i.attrs,
                     }),
-                _ => panic!("item FnLikeNode that is not fn-like"),
+                _ => bug!("item FnLikeNode that is not fn-like"),
             },
             map::NodeTraitItem(ti) => match ti.node {
                 ast::MethodTraitItem(ref sig, Some(ref body)) => {
                     method(ti.id, ti.name, sig, None, body, ti.span, &ti.attrs)
                 }
-                _ => panic!("trait method FnLikeNode that is not fn-like"),
+                _ => bug!("trait method FnLikeNode that is not fn-like"),
             },
             map::NodeImplItem(ii) => {
                 match ii.node {
                     ast::ImplItemKind::Method(ref sig, ref body) => {
                         method(ii.id, ii.name, sig, Some(ii.vis), body, ii.span, &ii.attrs)
                     }
                     _ => {
-                        panic!("impl method FnLikeNode that is not fn-like")
+                        bug!("impl method FnLikeNode that is not fn-like")
                     }
                 }
             }
@@ -256,9 +256,9 @@ impl<'a> FnLikeNode<'a> {
                                               e.id,
                                               e.span,
                                               e.attrs.as_attr_slice())),
-                _ => panic!("expr FnLikeNode that is not fn-like"),
+                _ => bug!("expr FnLikeNode that is not fn-like"),
             },
-            _ => panic!("other FnLikeNode that is not fn-like"),
+            _ => bug!("other FnLikeNode that is not fn-like"),
         }
     }
 }

src/librustc/front/map/mod.rs

@@ -335,9 +335,9 @@ impl<'ast> Map<'ast> {
                     return self.opt_local_def_id(id)
                                .map(|def_id| DepNode::Hir(def_id))
                                .unwrap_or_else(|| {
-                                   panic!("Walking parents from `{}` \
-                                           led to `NotPresent` at `{}`",
-                                          id0, id)
+                                   bug!("Walking parents from `{}` \
+                                         led to `NotPresent` at `{}`",
+                                        id0, id)
                                }),
             }
         }
@@ -363,8 +363,8 @@ impl<'ast> Map<'ast> {
 
     pub fn local_def_id(&self, node: NodeId) -> DefId {
         self.opt_local_def_id(node).unwrap_or_else(|| {
-            panic!("local_def_id: no entry for `{}`, which has a map of `{:?}`",
-                   node, self.find_entry(node))
+            bug!("local_def_id: no entry for `{}`, which has a map of `{:?}`",
+                 node, self.find_entry(node))
         })
     }
 
@@ -402,7 +402,7 @@ impl<'ast> Map<'ast> {
     pub fn get(&self, id: NodeId) -> Node<'ast> {
         match self.find(id) {
             Some(node) => node, // read recorded by `find`
-            None => panic!("couldn't find node id {} in the AST map", id)
+            None => bug!("couldn't find node id {} in the AST map", id)
         }
     }
 
@@ -576,22 +576,22 @@ impl<'ast> Map<'ast> {
                 self.read(id); // reveals some of the content of a node
                 abi
             }
-            None => panic!("expected foreign mod or inlined parent, found {}",
+            None => bug!("expected foreign mod or inlined parent, found {}",
                           self.node_to_string(parent))
         }
     }
 
     pub fn expect_item(&self, id: NodeId) -> &'ast Item {
         match self.find(id) { // read recorded by `find`
             Some(NodeItem(item)) => item,
-            _ => panic!("expected item, found {}", self.node_to_string(id))
+            _ => bug!("expected item, found {}", self.node_to_string(id))
         }
     }
 
     pub fn expect_trait_item(&self, id: NodeId) -> &'ast TraitItem {
         match self.find(id) {
             Some(NodeTraitItem(item)) => item,
-            _ => panic!("expected trait item, found {}", self.node_to_string(id))
+            _ => bug!("expected trait item, found {}", self.node_to_string(id))
         }
     }
 
@@ -600,38 +600,38 @@ impl<'ast> Map<'ast> {
             Some(NodeItem(i)) => {
                 match i.node {
                     ItemStruct(ref struct_def, _) => struct_def,
-                    _ => panic!("struct ID bound to non-struct")
+                    _ => bug!("struct ID bound to non-struct")
                 }
             }
             Some(NodeVariant(variant)) => {
                 if variant.node.data.is_struct() {
                     &variant.node.data
                 } else {
-                    panic!("struct ID bound to enum variant that isn't struct-like")
+                    bug!("struct ID bound to enum variant that isn't struct-like")
                 }
             }
-            _ => panic!(format!("expected struct, found {}", self.node_to_string(id))),
+            _ => bug!("expected struct, found {}", self.node_to_string(id)),
         }
     }
 
     pub fn expect_variant(&self, id: NodeId) -> &'ast Variant {
         match self.find(id) {
             Some(NodeVariant(variant)) => variant,
-            _ => panic!(format!("expected variant, found {}", self.node_to_string(id))),
+            _ => bug!("expected variant, found {}", self.node_to_string(id)),
         }
     }
 
     pub fn expect_foreign_item(&self, id: NodeId) -> &'ast ForeignItem {
         match self.find(id) {
             Some(NodeForeignItem(item)) => item,
-            _ => panic!("expected foreign item, found {}", self.node_to_string(id))
+            _ => bug!("expected foreign item, found {}", self.node_to_string(id))
         }
     }
 
     pub fn expect_expr(&self, id: NodeId) -> &'ast Expr {
         match self.find(id) { // read recorded by find
             Some(NodeExpr(expr)) => expr,
-            _ => panic!("expected expr, found {}", self.node_to_string(id))
+            _ => bug!("expected expr, found {}", self.node_to_string(id))
         }
     }
 
@@ -656,7 +656,7 @@ impl<'ast> Map<'ast> {
             NodeLocal(&Pat { node: PatKind::Ident(_,l,_), .. }) => {
                 PathName(l.node.name)
             },
-            _ => panic!("no path elem for {:?}", node)
+            _ => bug!("no path elem for {:?}", node)
         }
     }
 
@@ -773,7 +773,7 @@ impl<'ast> Map<'ast> {
     pub fn span(&self, id: NodeId) -> Span {
         self.read(id); // reveals span from node
         self.opt_span(id)
-            .unwrap_or_else(|| panic!("AstMap.span: could not find span for id {:?}", id))
+            .unwrap_or_else(|| bug!("AstMap.span: could not find span for id {:?}", id))
     }
 
     pub fn span_if_local(&self, id: DefId) -> Option<Span> {
@@ -1019,12 +1019,12 @@ impl<'a> NodePrinter for pprust::State<'a> {
             NodePat(a)         => self.print_pat(&a),
             NodeBlock(a)       => self.print_block(&a),
             NodeLifetime(a)    => self.print_lifetime(&a),
-            NodeTyParam(_)     => panic!("cannot print TyParam"),
+            NodeTyParam(_)     => bug!("cannot print TyParam"),
             // these cases do not carry enough information in the
             // ast_map to reconstruct their full structure for pretty
             // printing.
-            NodeLocal(_)       => panic!("cannot print isolated Local"),
-            NodeStructCtor(_)  => panic!("cannot print isolated StructCtor"),
+            NodeLocal(_)       => bug!("cannot print isolated Local"),
+            NodeStructCtor(_)  => bug!("cannot print isolated StructCtor"),
         }
     }
 }

src/librustc/infer/combine.rs

@@ -339,10 +339,10 @@ impl<'cx, 'tcx> ty::fold::TypeFolder<'tcx> for Generalizer<'cx, 'tcx> {
             // Early-bound regions should really have been substituted away before
             // we get to this point.
             ty::ReEarlyBound(..) => {
-                self.tcx().sess.span_bug(
+                span_bug!(
                     self.span,
-                    &format!("Encountered early bound region when generalizing: {:?}",
-                            r));
+                    "Encountered early bound region when generalizing: {:?}",
+                    r);
             }
 
             // Always make a fresh region variable for skolemized regions;

src/librustc/infer/error_reporting.rs

@@ -404,7 +404,7 @@ impl<'a, 'tcx> ErrorReporting<'tcx> for InferCtxt<'a, 'tcx> {
                     bound_failures.push((origin.clone(), kind.clone(), region));
                 }
                 ProcessedErrors(..) => {
-                    panic!("should not encounter a `ProcessedErrors` yet: {:?}", error)
+                    bug!("should not encounter a `ProcessedErrors` yet: {:?}", error)
                 }
             }
         }

src/librustc/infer/freshen.rs

@@ -140,11 +140,10 @@ impl<'a, 'tcx> TypeFolder<'tcx> for TypeFreshener<'a, 'tcx> {
             ty::TyInfer(ty::FreshIntTy(c)) |
             ty::TyInfer(ty::FreshFloatTy(c)) => {
                 if c >= self.freshen_count {
-                    tcx.sess.bug(
-                        &format!("Encountered a freshend type with id {} \
-                                  but our counter is only at {}",
-                                 c,
-                                 self.freshen_count));
+                    bug!("Encountered a freshend type with id {} \
+                          but our counter is only at {}",
+                         c,
+                         self.freshen_count);
                 }
                 t
             }

src/librustc/infer/higher_ranked/mod.rs

@@ -183,11 +183,10 @@ impl<'a,'tcx> HigherRankedRelations<'a,'tcx> for CombineFields<'a,'tcx> {
                 }
             }
 
-            infcx.tcx.sess.span_bug(
+            span_bug!(
                 span,
-                &format!("region {:?} is not associated with \
-                         any bound region from A!",
-                        r0))
+                "region {:?} is not associated with any bound region from A!",
+                r0)
         }
     }
 
@@ -297,7 +296,7 @@ impl<'a,'tcx> HigherRankedRelations<'a,'tcx> for CombineFields<'a,'tcx> {
 
             if a_r.is_some() && b_r.is_some() && only_new_vars {
                 // Related to exactly one bound variable from each fn:
-                return rev_lookup(infcx, span, a_map, a_r.unwrap());
+                return rev_lookup(span, a_map, a_r.unwrap());
             } else if a_r.is_none() && b_r.is_none() {
                 // Not related to bound variables from either fn:
                 assert!(!r0.is_bound());
@@ -308,8 +307,7 @@ impl<'a,'tcx> HigherRankedRelations<'a,'tcx> for CombineFields<'a,'tcx> {
             }
         }
 
-        fn rev_lookup(infcx: &InferCtxt,
-                      span: Span,
+        fn rev_lookup(span: Span,
                       a_map: &FnvHashMap<ty::BoundRegion, ty::Region>,
                       r: ty::Region) -> ty::Region
         {
@@ -318,9 +316,10 @@ impl<'a,'tcx> HigherRankedRelations<'a,'tcx> for CombineFields<'a,'tcx> {
                     return ty::ReLateBound(ty::DebruijnIndex::new(1), *a_br);
                 }
             }
-            infcx.tcx.sess.span_bug(
+            span_bug!(
                 span,
-                &format!("could not find original bound region for {:?}", r));
+                "could not find original bound region for {:?}",
+                r);
         }
 
         fn fresh_bound_variable(infcx: &InferCtxt, debruijn: ty::DebruijnIndex) -> ty::Region {
@@ -336,9 +335,10 @@ fn var_ids<'a, 'tcx>(fields: &CombineFields<'a, 'tcx>,
        .map(|(_, r)| match *r {
            ty::ReVar(r) => { r }
            r => {
-               fields.tcx().sess.span_bug(
+               span_bug!(
                    fields.trace.origin.span(),
-                   &format!("found non-region-vid: {:?}", r));
+                   "found non-region-vid: {:?}",
+                   r);
            }
        })
        .collect()

src/librustc/infer/mod.rs

@@ -471,7 +471,7 @@ pub fn mk_eq_impl_headers<'a, 'tcx>(cx: &InferCtxt<'a, 'tcx>,
     match (a.trait_ref, b.trait_ref) {
         (Some(a_ref), Some(b_ref)) => mk_eq_trait_refs(cx, a_is_expected, origin, a_ref, b_ref),
         (None, None) => mk_eqty(cx, a_is_expected, origin, a.self_ty, b.self_ty),
-        _ => cx.tcx.sess.bug("mk_eq_impl_headers given mismatched impl kinds"),
+        _ => bug!("mk_eq_impl_headers given mismatched impl kinds"),
     }
 }
 
@@ -536,10 +536,10 @@ pub fn drain_fulfillment_cx_or_panic<'a,'tcx,T>(span: Span,
     match drain_fulfillment_cx(infcx, fulfill_cx, result) {
         Ok(v) => v,
         Err(errors) => {
-            infcx.tcx.sess.span_bug(
+            span_bug!(
                 span,
-                &format!("Encountered errors `{:?}` fulfilling during trans",
-                         errors));
+                "Encountered errors `{:?}` fulfilling during trans",
+                errors);
         }
     }
 }
@@ -1114,9 +1114,8 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             None if self.errors_since_creation() =>
                 self.tcx.types.err,
             None => {
-                self.tcx.sess.bug(
-                    &format!("no type for node {}: {} in fcx",
-                            id, self.tcx.map.node_to_string(id)));
+                bug!("no type for node {}: {} in fcx",
+                     id, self.tcx.map.node_to_string(id));
             }
         }
     }
@@ -1125,7 +1124,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         match self.tables.borrow().node_types.get(&ex.id) {
             Some(&t) => t,
             None => {
-                self.tcx.sess.bug("no type for expr in fcx");
+                bug!("no type for expr in fcx");
             }
         }
     }

src/librustc/infer/region_inference/graphviz.rs

@@ -90,7 +90,7 @@ pub fn maybe_print_constraints_for<'a, 'tcx>(region_vars: &RegionVarBindings<'a,
         };
 
         if output_template.is_empty() {
-            tcx.sess.bug("empty string provided as RUST_REGION_GRAPH");
+            bug!("empty string provided as RUST_REGION_GRAPH");
         }
 
         if output_template.contains('%') {
@@ -182,13 +182,13 @@ impl<'a, 'tcx> dot::Labeller<'a> for ConstraintGraph<'a, 'tcx> {
     fn node_id(&self, n: &Node) -> dot::Id {
         let node_id = match self.node_ids.get(n) {
             Some(node_id) => node_id,
-            None => panic!("no node_id found for node: {:?}", n),
+            None => bug!("no node_id found for node: {:?}", n),
         };
         let name = || format!("node_{}", node_id);
         match dot::Id::new(name()) {
             Ok(id) => id,
             Err(_) => {
-                panic!("failed to create graphviz node identified by {}", name());
+                bug!("failed to create graphviz node identified by {}", name());
             }
         }
     }