Rollup merge of #123016 - compiler-errors:no-type-var-origin, r=lcnr

Remove `TypeVariableOriginKind` and `ConstVariableOriginKind`

It's annoying to have to import `TypeVariableOriginKind` just to fill it with `MiscVariable` for almost every use. Every other usage other than `TypeParameterDefinition` wasn't even used -- I can see how it may have been useful once for debugging, but I do quite a lot of typeck debugging and I've never really needed it.

So let's just remove it, and keep around the only useful thing which is the `DefId` of the param for `var_for_def`.

This is based on #123006, which removed the special use of `TypeVariableOriginKind::OpaqueInference`, which I'm pretty sure I was the one that added.

r? lcnr or re-roll to types

compiler/rustc_trait_selection/src/traits/error_reporting/infer_ctxt_ext.rs

@@ -1,4 +1,4 @@
-use crate::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
+use crate::infer::type_variable::TypeVariableOrigin;
 use crate::infer::InferCtxt;
 use crate::traits::{Obligation, ObligationCause, ObligationCtxt};
 use rustc_errors::{codes::*, pluralize, struct_span_code_err, Applicability, Diag};
@@ -217,10 +217,8 @@ impl<'tcx> InferCtxt<'tcx> {
                 let Some(trait_def_id) = trait_def_id else { continue };
                 // Make a fresh inference variable so we can determine what the generic parameters
                 // of the trait are.
-                let var = self.next_ty_var(TypeVariableOrigin {
-                    span: DUMMY_SP,
-                    kind: TypeVariableOriginKind::MiscVariable,
-                });
+                let var =
+                    self.next_ty_var(TypeVariableOrigin { span: DUMMY_SP, param_def_id: None });
                 // FIXME(effects)
                 let trait_ref = ty::TraitRef::new(self.tcx, trait_def_id, [ty.skip_binder(), var]);
                 let obligation = Obligation::new(

compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs

@@ -24,7 +24,7 @@ use rustc_hir::is_range_literal;
 use rustc_hir::lang_items::LangItem;
 use rustc_hir::{CoroutineDesugaring, CoroutineKind, CoroutineSource, Expr, HirId, Node};
 use rustc_infer::infer::error_reporting::TypeErrCtxt;
-use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
+use rustc_infer::infer::type_variable::TypeVariableOrigin;
 use rustc_infer::infer::{BoundRegionConversionTime, DefineOpaqueTypes, InferOk};
 use rustc_middle::hir::map;
 use rustc_middle::traits::IsConstable;
@@ -1894,10 +1894,8 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                 ty::Tuple(inputs) if infcx.tcx.is_fn_trait(trait_ref.def_id) => {
                     infcx.tcx.mk_fn_sig(
                         *inputs,
-                        infcx.next_ty_var(TypeVariableOrigin {
-                            span: DUMMY_SP,
-                            kind: TypeVariableOriginKind::MiscVariable,
-                        }),
+                        infcx
+                            .next_ty_var(TypeVariableOrigin { span: DUMMY_SP, param_def_id: None }),
                         false,
                         hir::Unsafety::Normal,
                         abi::Abi::Rust,
@@ -1905,10 +1903,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                 }
                 _ => infcx.tcx.mk_fn_sig(
                     [inputs],
-                    infcx.next_ty_var(TypeVariableOrigin {
-                        span: DUMMY_SP,
-                        kind: TypeVariableOriginKind::MiscVariable,
-                    }),
+                    infcx.next_ty_var(TypeVariableOrigin { span: DUMMY_SP, param_def_id: None }),
                     false,
                     hir::Unsafety::Normal,
                     abi::Abi::Rust,
@@ -4269,7 +4264,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                 continue;
             };
 
-            let origin = TypeVariableOrigin { kind: TypeVariableOriginKind::TypeInference, span };
+            let origin = TypeVariableOrigin { param_def_id: None, span };
             // Make `Self` be equivalent to the type of the call chain
             // expression we're looking at now, so that we can tell what
             // for example `Iterator::Item` is at this point in the chain.

compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs

@@ -6,7 +6,7 @@ use crate::errors::{
     AsyncClosureNotFn, ClosureFnMutLabel, ClosureFnOnceLabel, ClosureKindMismatch,
 };
 use crate::infer::error_reporting::{TyCategory, TypeAnnotationNeeded as ErrorCode};
-use crate::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
+use crate::infer::type_variable::TypeVariableOrigin;
 use crate::infer::InferCtxtExt as _;
 use crate::infer::{self, InferCtxt};
 use crate::traits::error_reporting::infer_ctxt_ext::InferCtxtExt;
@@ -2820,10 +2820,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                 if let ty::Param(_) = *ty.kind() {
                     let infcx = self.infcx;
                     *self.var_map.entry(ty).or_insert_with(|| {
-                        infcx.next_ty_var(TypeVariableOrigin {
-                            kind: TypeVariableOriginKind::MiscVariable,
-                            span: DUMMY_SP,
-                        })
+                        infcx.next_ty_var(TypeVariableOrigin { param_def_id: None, span: DUMMY_SP })
                     })
                 } else {
                     ty.super_fold_with(self)

compiler/rustc_trait_selection/src/traits/project.rs

@@ -18,7 +18,7 @@ use rustc_middle::traits::ImplSource;
 use rustc_middle::traits::ImplSourceUserDefinedData;
 
 use crate::errors::InherentProjectionNormalizationOverflow;
-use crate::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
+use crate::infer::type_variable::TypeVariableOrigin;
 use crate::infer::{BoundRegionConversionTime, InferOk};
 use crate::traits::normalize::normalize_with_depth;
 use crate::traits::normalize::normalize_with_depth_to;
@@ -522,7 +522,7 @@ fn normalize_to_error<'a, 'tcx>(
     };
     let tcx = selcx.infcx.tcx;
     let new_value = selcx.infcx.next_ty_var(TypeVariableOrigin {
-        kind: TypeVariableOriginKind::NormalizeProjectionType,
+        param_def_id: None,
         span: tcx.def_span(projection_ty.def_id),
     });
     Normalized { value: new_value, obligations: vec![trait_obligation] }

compiler/rustc_trait_selection/src/traits/structural_normalize.rs

@@ -1,5 +1,5 @@
 use rustc_infer::infer::at::At;
-use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
+use rustc_infer::infer::type_variable::TypeVariableOrigin;
 use rustc_infer::traits::{FulfillmentError, TraitEngine};
 use rustc_middle::ty::{self, Ty};
 
@@ -19,10 +19,9 @@ impl<'tcx> At<'_, 'tcx> {
                 return Ok(ty);
             };
 
-            let new_infer_ty = self.infcx.next_ty_var(TypeVariableOrigin {
-                kind: TypeVariableOriginKind::NormalizeProjectionType,
-                span: self.cause.span,
-            });
+            let new_infer_ty = self
+                .infcx
+                .next_ty_var(TypeVariableOrigin { param_def_id: None, span: self.cause.span });
 
             // We simply emit an `alias-eq` goal here, since that will take care of
             // normalizing the LHS of the projection until it is a rigid projection