Auto merge of rust-lang#16388 - Veykril:fn-abi, r=Veykril

internal: Record FnAbi

This unfortunately breaks our lub coercions, so will need to look into fixing that first, though I am not sure what is going wrong where...

Stubbed some stuff out for the time being.

crates/hir-def/src/hir/type_ref.rs

@@ -10,7 +10,7 @@ use hir_expand::{
     AstId,
 };
 use intern::Interned;
-use syntax::ast::{self, HasName};
+use syntax::ast::{self, HasName, IsString};
 
 use crate::{
     builtin_type::{BuiltinInt, BuiltinType, BuiltinUint},
@@ -120,7 +120,12 @@ pub enum TypeRef {
     Array(Box<TypeRef>, ConstRef),
     Slice(Box<TypeRef>),
     /// A fn pointer. Last element of the vector is the return type.
-    Fn(Vec<(Option<Name>, TypeRef)>, bool /*varargs*/, bool /*is_unsafe*/),
+    Fn(
+        Vec<(Option<Name>, TypeRef)>,
+        bool,                  /*varargs*/
+        bool,                  /*is_unsafe*/
+        Option<Interned<str>>, /* abi */
+    ),
     ImplTrait(Vec<Interned<TypeBound>>),
     DynTrait(Vec<Interned<TypeBound>>),
     Macro(AstId<ast::MacroCall>),
@@ -225,8 +230,17 @@ impl TypeRef {
                 } else {
                     Vec::new()
                 };
+                fn lower_abi(abi: ast::Abi) -> Interned<str> {
+                    match abi.abi_string() {
+                        Some(tok) => Interned::new_str(tok.text_without_quotes()),
+                        // `extern` default to be `extern "C"`.
+                        _ => Interned::new_str("C"),
+                    }
+                }
+
+                let abi = inner.abi().map(lower_abi);
                 params.push((None, ret_ty));
-                TypeRef::Fn(params, is_varargs, inner.unsafe_token().is_some())
+                TypeRef::Fn(params, is_varargs, inner.unsafe_token().is_some(), abi)
             }
             // for types are close enough for our purposes to the inner type for now...
             ast::Type::ForType(inner) => TypeRef::from_ast_opt(ctx, inner.ty()),
@@ -260,7 +274,7 @@ impl TypeRef {
         fn go(type_ref: &TypeRef, f: &mut impl FnMut(&TypeRef)) {
             f(type_ref);
             match type_ref {
-                TypeRef::Fn(params, _, _) => {
+                TypeRef::Fn(params, _, _, _) => {
                     params.iter().for_each(|(_, param_type)| go(param_type, f))
                 }
                 TypeRef::Tuple(types) => types.iter().for_each(|t| go(t, f)),

crates/hir-def/src/item_tree/lower.rs

@@ -3,7 +3,7 @@
 use std::collections::hash_map::Entry;
 
 use hir_expand::{ast_id_map::AstIdMap, span_map::SpanMapRef, HirFileId};
-use syntax::ast::{self, HasModuleItem, HasTypeBounds};
+use syntax::ast::{self, HasModuleItem, HasTypeBounds, IsString};
 
 use crate::{
     generics::{GenericParams, GenericParamsCollector, TypeParamData, TypeParamProvenance},
@@ -721,16 +721,10 @@ enum HasImplicitSelf {
 }
 
 fn lower_abi(abi: ast::Abi) -> Interned<str> {
-    // FIXME: Abi::abi() -> Option<SyntaxToken>?
-    match abi.syntax().last_token() {
-        Some(tok) if tok.kind() == SyntaxKind::STRING => {
-            // FIXME: Better way to unescape?
-            Interned::new_str(tok.text().trim_matches('"'))
-        }
-        _ => {
-            // `extern` default to be `extern "C"`.
-            Interned::new_str("C")
-        }
+    match abi.abi_string() {
+        Some(tok) => Interned::new_str(tok.text_without_quotes()),
+        // `extern` default to be `extern "C"`.
+        _ => Interned::new_str("C"),
     }
 }
 

crates/hir-def/src/pretty.rs

@@ -192,12 +192,17 @@ pub(crate) fn print_type_ref(
             print_type_ref(db, elem, buf)?;
             write!(buf, "]")?;
         }
-        TypeRef::Fn(args_and_ret, varargs, is_unsafe) => {
+        TypeRef::Fn(args_and_ret, varargs, is_unsafe, abi) => {
             let ((_, return_type), args) =
                 args_and_ret.split_last().expect("TypeRef::Fn is missing return type");
             if *is_unsafe {
                 write!(buf, "unsafe ")?;
             }
+            if let Some(abi) = abi {
+                buf.write_str("extern ")?;
+                buf.write_str(abi)?;
+                buf.write_char(' ')?;
+            }
             write!(buf, "fn(")?;
             for (i, (_, typeref)) in args.iter().enumerate() {
                 if i != 0 {

crates/hir-ty/src/chalk_db.rs

@@ -819,7 +819,11 @@ pub(crate) fn fn_def_datum_query(
     };
     let datum = FnDefDatum {
         id: fn_def_id,
-        sig: chalk_ir::FnSig { abi: (), safety: chalk_ir::Safety::Safe, variadic: sig.is_varargs },
+        sig: chalk_ir::FnSig {
+            abi: sig.abi,
+            safety: chalk_ir::Safety::Safe,
+            variadic: sig.is_varargs,
+        },
         binders: chalk_ir::Binders::new(binders, bound),
     };
     Arc::new(datum)

crates/hir-ty/src/chalk_ext.rs

@@ -202,11 +202,7 @@ impl TyExt for Ty {
     fn callable_sig(&self, db: &dyn HirDatabase) -> Option<CallableSig> {
         match self.kind(Interner) {
             TyKind::Function(fn_ptr) => Some(CallableSig::from_fn_ptr(fn_ptr)),
-            TyKind::FnDef(def, parameters) => {
-                let callable_def = db.lookup_intern_callable_def((*def).into());
-                let sig = db.callable_item_signature(callable_def);
-                Some(sig.substitute(Interner, parameters))
-            }
+            TyKind::FnDef(def, parameters) => Some(CallableSig::from_def(db, *def, parameters)),
             TyKind::Closure(.., substs) => ClosureSubst(substs).sig_ty().callable_sig(db),
             _ => None,
         }

crates/hir-ty/src/display.rs

@@ -8,7 +8,7 @@ use std::{
 };
 
 use base_db::CrateId;
-use chalk_ir::{BoundVar, TyKind};
+use chalk_ir::{BoundVar, Safety, TyKind};
 use hir_def::{
     data::adt::VariantData,
     db::DefDatabase,
@@ -41,7 +41,7 @@ use crate::{
     primitive, to_assoc_type_id,
     utils::{self, detect_variant_from_bytes, generics, ClosureSubst},
     AdtId, AliasEq, AliasTy, Binders, CallableDefId, CallableSig, Const, ConstScalar, ConstValue,
-    DomainGoal, GenericArg, ImplTraitId, Interner, Lifetime, LifetimeData, LifetimeOutlives,
+    DomainGoal, FnAbi, GenericArg, ImplTraitId, Interner, Lifetime, LifetimeData, LifetimeOutlives,
     MemoryMap, Mutability, OpaqueTy, ProjectionTy, ProjectionTyExt, QuantifiedWhereClause, Scalar,
     Substitution, TraitEnvironment, TraitRef, TraitRefExt, Ty, TyExt, WhereClause,
 };
@@ -879,16 +879,27 @@ impl HirDisplay for Ty {
                     // function pointer type.
                     return sig.hir_fmt(f);
                 }
+                if let Safety::Unsafe = sig.safety {
+                    write!(f, "unsafe ")?;
+                }
+                if !matches!(sig.abi, FnAbi::Rust) {
+                    f.write_str("extern \"")?;
+                    f.write_str(sig.abi.as_str())?;
+                    f.write_str("\" ")?;
+                }
 
-                f.start_location_link(def.into());
                 match def {
                     CallableDefId::FunctionId(ff) => {
-                        write!(f, "fn {}", db.function_data(ff).name.display(f.db.upcast()))?
+                        write!(f, "fn ")?;
+                        f.start_location_link(def.into());
+                        write!(f, "{}", db.function_data(ff).name.display(f.db.upcast()))?
                     }
                     CallableDefId::StructId(s) => {
+                        f.start_location_link(def.into());
                         write!(f, "{}", db.struct_data(s).name.display(f.db.upcast()))?
                     }
                     CallableDefId::EnumVariantId(e) => {
+                        f.start_location_link(def.into());
                         write!(f, "{}", db.enum_variant_data(e).name.display(f.db.upcast()))?
                     }
                 };
@@ -1316,9 +1327,19 @@ fn hir_fmt_generics(
 
 impl HirDisplay for CallableSig {
     fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
+        let CallableSig { params_and_return: _, is_varargs, safety, abi: _ } = *self;
+        if let Safety::Unsafe = safety {
+            write!(f, "unsafe ")?;
+        }
+        // FIXME: Enable this when the FIXME on FnAbi regarding PartialEq is fixed.
+        // if !matches!(abi, FnAbi::Rust) {
+        //     f.write_str("extern \"")?;
+        //     f.write_str(abi.as_str())?;
+        //     f.write_str("\" ")?;
+        // }
         write!(f, "fn(")?;
         f.write_joined(self.params(), ", ")?;
-        if self.is_varargs {
+        if is_varargs {
             if self.params().is_empty() {
                 write!(f, "...")?;
             } else {
@@ -1683,11 +1704,15 @@ impl HirDisplay for TypeRef {
                 inner.hir_fmt(f)?;
                 write!(f, "]")?;
             }
-            &TypeRef::Fn(ref parameters, is_varargs, is_unsafe) => {
-                // FIXME: Function pointer qualifiers.
+            &TypeRef::Fn(ref parameters, is_varargs, is_unsafe, ref abi) => {
                 if is_unsafe {
                     write!(f, "unsafe ")?;
                 }
+                if let Some(abi) = abi {
+                    f.write_str("extern \"")?;
+                    f.write_str(abi)?;
+                    f.write_str("\" ")?;
+                }
                 write!(f, "fn(")?;
                 if let Some(((_, return_type), function_parameters)) = parameters.split_last() {
                     for index in 0..function_parameters.len() {

crates/hir-ty/src/infer.rs

@@ -1453,10 +1453,10 @@ impl Expectation {
         match self {
             Expectation::HasType(ety) => {
                 let ety = table.resolve_ty_shallow(ety);
-                if !ety.is_ty_var() {
-                    Expectation::HasType(ety)
-                } else {
+                if ety.is_ty_var() {
                     Expectation::None
+                } else {
+                    Expectation::HasType(ety)
                 }
             }
             Expectation::RValueLikeUnsized(ety) => Expectation::RValueLikeUnsized(ety.clone()),

crates/hir-ty/src/infer/closure.rs

@@ -27,8 +27,8 @@ use crate::{
     static_lifetime, to_chalk_trait_id,
     traits::FnTrait,
     utils::{self, generics, Generics},
-    Adjust, Adjustment, Binders, BindingMode, ChalkTraitId, ClosureId, DynTy, FnPointer, FnSig,
-    Interner, Substitution, Ty, TyExt,
+    Adjust, Adjustment, Binders, BindingMode, ChalkTraitId, ClosureId, DynTy, FnAbi, FnPointer,
+    FnSig, Interner, Substitution, Ty, TyExt,
 };
 
 use super::{Expectation, InferenceContext};
@@ -98,7 +98,11 @@ impl InferenceContext<'_> {
                     cov_mark::hit!(dyn_fn_param_informs_call_site_closure_signature);
                     return Some(FnPointer {
                         num_binders: bound.len(Interner),
-                        sig: FnSig { abi: (), safety: chalk_ir::Safety::Safe, variadic: false },
+                        sig: FnSig {
+                            abi: FnAbi::RustCall,
+                            safety: chalk_ir::Safety::Safe,
+                            variadic: false,
+                        },
                         substitution: FnSubst(Substitution::from_iter(Interner, sig_tys)),
                     });
                 }

crates/hir-ty/src/infer/coerce.rs

@@ -24,7 +24,7 @@ use crate::{
     },
     static_lifetime,
     utils::ClosureSubst,
-    Canonical, DomainGoal, FnPointer, FnSig, Guidance, InEnvironment, Interner, Solution,
+    Canonical, DomainGoal, FnAbi, FnPointer, FnSig, Guidance, InEnvironment, Interner, Solution,
     Substitution, TraitEnvironment, Ty, TyBuilder, TyExt,
 };
 
@@ -691,7 +691,7 @@ fn coerce_closure_fn_ty(closure_substs: &Substitution, safety: chalk_ir::Safety)
     match closure_sig.kind(Interner) {
         TyKind::Function(fn_ty) => TyKind::Function(FnPointer {
             num_binders: fn_ty.num_binders,
-            sig: FnSig { safety, ..fn_ty.sig },
+            sig: FnSig { safety, abi: FnAbi::Rust, variadic: fn_ty.sig.variadic },
             substitution: fn_ty.substitution.clone(),
         })
         .intern(Interner),

crates/hir-ty/src/infer/expr.rs

@@ -39,9 +39,9 @@ use crate::{
     static_lifetime, to_chalk_trait_id,
     traits::FnTrait,
     utils::{generics, Generics},
-    Adjust, Adjustment, AdtId, AutoBorrow, Binders, CallableDefId, FnPointer, FnSig, FnSubst,
-    Interner, Rawness, Scalar, Substitution, TraitEnvironment, TraitRef, Ty, TyBuilder, TyExt,
-    TyKind,
+    Adjust, Adjustment, AdtId, AutoBorrow, Binders, CallableDefId, FnAbi, FnPointer, FnSig,
+    FnSubst, Interner, Rawness, Scalar, Substitution, TraitEnvironment, TraitRef, Ty, TyBuilder,
+    TyExt, TyKind,
 };
 
 use super::{
@@ -224,7 +224,11 @@ impl InferenceContext<'_> {
 
                 let sig_ty = TyKind::Function(FnPointer {
                     num_binders: 0,
-                    sig: FnSig { abi: (), safety: chalk_ir::Safety::Safe, variadic: false },
+                    sig: FnSig {
+                        abi: FnAbi::RustCall,
+                        safety: chalk_ir::Safety::Safe,
+                        variadic: false,
+                    },
                     substitution: FnSubst(
                         Substitution::from_iter(Interner, sig_tys.iter().cloned())
                             .shifted_in(Interner),

crates/hir-ty/src/interner.rs

@@ -3,8 +3,8 @@
 
 use crate::{
     chalk_db, tls, AliasTy, CanonicalVarKind, CanonicalVarKinds, ClosureId, Const, ConstData,
-    ConstScalar, Constraint, Constraints, FnDefId, GenericArg, GenericArgData, Goal, GoalData,
-    Goals, InEnvironment, Lifetime, LifetimeData, OpaqueTy, OpaqueTyId, ProgramClause,
+    ConstScalar, Constraint, Constraints, FnAbi, FnDefId, GenericArg, GenericArgData, Goal,
+    GoalData, Goals, InEnvironment, Lifetime, LifetimeData, OpaqueTy, OpaqueTyId, ProgramClause,
     ProgramClauseData, ProgramClauses, ProjectionTy, QuantifiedWhereClause, QuantifiedWhereClauses,
     Substitution, Ty, TyData, TyKind, VariableKind, VariableKinds,
 };
@@ -71,7 +71,7 @@ impl chalk_ir::interner::Interner for Interner {
     type DefId = InternId;
     type InternedAdtId = hir_def::AdtId;
     type Identifier = TypeAliasId;
-    type FnAbi = ();
+    type FnAbi = FnAbi;
 
     fn debug_adt_id(
         type_kind_id: chalk_db::AdtId,