Auto merge of #126736 - matthiaskrgr:rollup-rb20oe3, r=matthiaskrgr

Rollup of 7 pull requests

Successful merges:

 - #126380 (Add std Xtensa targets support)
 - #126636 (Resolve Clippy `f16` and `f128` `unimplemented!`/`FIXME`s )
 - #126659 (More status-quo tests for the `#[coverage(..)]` attribute)
 - #126711 (Make Option::as_[mut_]slice const)
 - #126717 (Clean up some comments near `use` declarations)
 - #126719 (Fix assertion failure for some `Expect` diagnostics.)
 - #126730 (Add opaque type corner case test)

r? `@ghost`
`@rustbot` modify labels: rollup

compiler/rustc_builtin_macros/src/test.rs

@@ -1,6 +1,7 @@
+//! The expansion from a test function to the appropriate test struct for libtest
+//! Ideally, this code would be in libtest but for efficiency and error messages it lives here.
+
 use crate::errors;
-/// The expansion from a test function to the appropriate test struct for libtest
-/// Ideally, this code would be in libtest but for efficiency and error messages it lives here.
 use crate::util::{check_builtin_macro_attribute, warn_on_duplicate_attribute};
 use rustc_ast::ptr::P;
 use rustc_ast::{self as ast, attr, GenericParamKind};

compiler/rustc_codegen_gcc/tests/lang_tests_common.rs

@@ -1,4 +1,5 @@
 //! The common code for `tests/lang_tests_*.rs`
+
 use std::{
     env::{self, current_dir},
     path::{Path, PathBuf},

compiler/rustc_codegen_ssa/src/mir/locals.rs

@@ -1,6 +1,7 @@
 //! Locals are in a private module as updating `LocalRef::Operand` has to
 //! be careful wrt to subtyping. To deal with this we only allow updates by using
 //! `FunctionCx::overwrite_local` which handles it automatically.
+
 use crate::mir::{FunctionCx, LocalRef};
 use crate::traits::BuilderMethods;
 use rustc_index::IndexVec;

compiler/rustc_data_structures/src/base_n.rs

@@ -1,5 +1,6 @@
-/// Converts unsigned integers into a string representation with some base.
-/// Bases up to and including 36 can be used for case-insensitive things.
+//! Converts unsigned integers into a string representation with some base.
+//! Bases up to and including 36 can be used for case-insensitive things.
+
 use std::ascii;
 use std::fmt;
 

compiler/rustc_errors/src/lib.rs

@@ -1437,6 +1437,24 @@ impl DiagCtxtInner {
 
     // Return value is only `Some` if the level is `Error` or `DelayedBug`.
     fn emit_diagnostic(&mut self, mut diagnostic: DiagInner) -> Option<ErrorGuaranteed> {
+        match diagnostic.level {
+            Expect(expect_id) | ForceWarning(Some(expect_id)) => {
+                // The `LintExpectationId` can be stable or unstable depending on when it was
+                // created. Diagnostics created before the definition of `HirId`s are unstable and
+                // can not yet be stored. Instead, they are buffered until the `LintExpectationId`
+                // is replaced by a stable one by the `LintLevelsBuilder`.
+                if let LintExpectationId::Unstable { .. } = expect_id {
+                    // We don't call TRACK_DIAGNOSTIC because we wait for the
+                    // unstable ID to be updated, whereupon the diagnostic will be
+                    // passed into this method again.
+                    self.unstable_expect_diagnostics.push(diagnostic);
+                    return None;
+                }
+                // Continue through to the `Expect`/`ForceWarning` case below.
+            }
+            _ => {}
+        }
+
         if diagnostic.has_future_breakage() {
             // Future breakages aren't emitted if they're `Level::Allow`,
             // but they still need to be constructed and stashed below,
@@ -1512,16 +1530,8 @@ impl DiagCtxtInner {
                 return None;
             }
             Expect(expect_id) | ForceWarning(Some(expect_id)) => {
-                // Diagnostics created before the definition of `HirId`s are
-                // unstable and can not yet be stored. Instead, they are
-                // buffered until the `LintExpectationId` is replaced by a
-                // stable one by the `LintLevelsBuilder`.
                 if let LintExpectationId::Unstable { .. } = expect_id {
-                    // We don't call TRACK_DIAGNOSTIC because we wait for the
-                    // unstable ID to be updated, whereupon the diagnostic will
-                    // be passed into this method again.
-                    self.unstable_expect_diagnostics.push(diagnostic);
-                    return None;
+                    unreachable!(); // this case was handled at the top of this function
                 }
                 self.fulfilled_expectations.insert(expect_id.normalize());
                 if let Expect(_) = diagnostic.level {

compiler/rustc_errors/src/markdown/mod.rs

@@ -1,6 +1,7 @@
 //! A simple markdown parser that can write formatted text to the terminal
 //!
 //! Entrypoint is `MdStream::parse_str(...)`
+
 use std::io;
 
 use termcolor::{Buffer, BufferWriter, ColorChoice};

compiler/rustc_expand/src/mbe/macro_check.rs

@@ -104,6 +104,7 @@
 //! Kleene operators under which a meta-variable is repeating is the concatenation of the stacks
 //! stored when entering a macro definition starting from the state in which the meta-variable is
 //! bound.
+
 use crate::errors;
 use crate::mbe::{KleeneToken, TokenTree};
 

compiler/rustc_fs_util/src/lib.rs

@@ -1,9 +1,7 @@
-// tidy-alphabetical-start
 use std::ffi::CString;
 use std::fs;
 use std::io;
 use std::path::{absolute, Path, PathBuf};
-// tidy-alphabetical-end
 
 // Unfortunately, on windows, it looks like msvcrt.dll is silently translating
 // verbatim paths under the hood to non-verbatim paths! This manifests itself as

compiler/rustc_hir_analysis/src/check/dropck.rs

@@ -1,6 +1,7 @@
 // FIXME(@lcnr): Move this module out of `rustc_hir_analysis`.
 //
 // We don't do any drop checking during hir typeck.
+
 use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::{codes::*, struct_span_code_err, ErrorGuaranteed};
 use rustc_infer::infer::outlives::env::OutlivesEnvironment;

compiler/rustc_hir_typeck/src/autoderef.rs

@@ -1,4 +1,5 @@
-//! Some helper functions for `AutoDeref`
+//! Some helper functions for `AutoDeref`.
+
 use super::method::MethodCallee;
 use super::{FnCtxt, PlaceOp};
 

compiler/rustc_hir_typeck/src/errors.rs

@@ -1,4 +1,5 @@
 //! Errors emitted by `rustc_hir_typeck`.
+
 use std::borrow::Cow;
 
 use crate::fluent_generated as fluent;

compiler/rustc_hir_typeck/src/fn_ctxt/inspect_obligations.rs

@@ -1,4 +1,5 @@
 //! A utility module to inspect currently ambiguous obligations in the current context.
+
 use crate::FnCtxt;
 use rustc_infer::traits::{self, ObligationCause};
 use rustc_middle::traits::solve::Goal;

compiler/rustc_infer/src/infer/error_reporting/nice_region_error/named_anon_conflict.rs

@@ -1,5 +1,6 @@
 //! Error Reporting for Anonymous Region Lifetime Errors
 //! where one region is named and the other is anonymous.
+
 use crate::infer::error_reporting::nice_region_error::NiceRegionError;
 use crate::{
     errors::ExplicitLifetimeRequired,

compiler/rustc_infer/src/infer/freshen.rs

@@ -30,6 +30,7 @@
 //! solving a set of constraints. In contrast, the type inferencer assigns a value to each type
 //! variable only once, and it does so as soon as it can, so it is reasonable to ask what the type
 //! inferencer knows "so far".
+
 use super::InferCtxt;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_middle::bug;

compiler/rustc_infer/src/infer/outlives/mod.rs

@@ -1,4 +1,5 @@
 //! Various code related to computing outlives relations.
+
 use self::env::OutlivesEnvironment;
 use super::region_constraints::RegionConstraintData;
 use super::{InferCtxt, RegionResolutionError, SubregionOrigin};

compiler/rustc_lint_defs/src/lib.rs

@@ -1,4 +1,3 @@
-// tidy-alphabetical-start
 pub use self::Level::*;
 use rustc_ast::node_id::NodeId;
 use rustc_ast::{AttrId, Attribute};
@@ -15,7 +14,6 @@ use rustc_span::edition::Edition;
 use rustc_span::symbol::MacroRulesNormalizedIdent;
 use rustc_span::{sym, symbol::Ident, Span, Symbol};
 use rustc_target::spec::abi::Abi;
-// tidy-alphabetical-end
 
 use serde::{Deserialize, Serialize};
 

compiler/rustc_middle/src/middle/privacy.rs

@@ -1,6 +1,7 @@
 //! A pass that checks to make sure private fields and methods aren't used
 //! outside their scopes. This pass will also generate a set of exported items
 //! which are available for use externally when compiled as a library.
+
 use crate::ty::{TyCtxt, Visibility};
 use rustc_data_structures::fx::{FxIndexMap, IndexEntry};
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};

compiler/rustc_middle/src/mir/statement.rs

@@ -1,4 +1,5 @@
-/// Functionality for statements, operands, places, and things that appear in them.
+//! Functionality for statements, operands, places, and things that appear in them.
+
 use super::{interpret::GlobalAlloc, *};
 
 ///////////////////////////////////////////////////////////////////////////

compiler/rustc_middle/src/mir/terminator.rs

@@ -1,4 +1,5 @@
-/// Functionality for terminators and helper types that appear in terminators.
+//! Functionality for terminators and helper types that appear in terminators.
+
 use rustc_hir::LangItem;
 use smallvec::{smallvec, SmallVec};
 

compiler/rustc_middle/src/ty/abstract_const.rs

@@ -1,4 +1,5 @@
 //! A subset of a mir body used for const evaluability checking.
+
 use crate::ty::{
     self, Const, EarlyBinder, Ty, TyCtxt, TypeFoldable, TypeFolder, TypeSuperFoldable,
     TypeVisitableExt,

compiler/rustc_mir_transform/src/ctfe_limit.rs

@@ -1,5 +1,6 @@
 //! A pass that inserts the `ConstEvalCounter` instruction into any blocks that have a back edge
 //! (thus indicating there is a loop in the CFG), or whose terminator is a function call.
+
 use crate::MirPass;
 
 use rustc_data_structures::graph::dominators::Dominators;

compiler/rustc_mir_transform/src/inline.rs

@@ -1,4 +1,5 @@
-//! Inlining pass for MIR functions
+//! Inlining pass for MIR functions.
+
 use crate::deref_separator::deref_finder;
 use rustc_attr::InlineAttr;
 use rustc_hir::def::DefKind;

compiler/rustc_mir_transform/src/lint.rs

@@ -1,6 +1,7 @@
 //! This pass statically detects code which has undefined behaviour or is likely to be erroneous.
 //! It can be used to locate problems in MIR building or optimizations. It assumes that all code
 //! can be executed, so it has false positives.
+
 use rustc_data_structures::fx::FxHashSet;
 use rustc_index::bit_set::BitSet;
 use rustc_middle::mir::visit::{PlaceContext, Visitor};

compiler/rustc_parse/src/parser/expr.rs

@@ -1,4 +1,5 @@
 // ignore-tidy-filelength
+
 use super::diagnostics::SnapshotParser;
 use super::pat::{CommaRecoveryMode, Expected, RecoverColon, RecoverComma};
 use super::ty::{AllowPlus, RecoverQPath, RecoverReturnSign};

compiler/rustc_pattern_analysis/src/pat.rs

@@ -1,5 +1,6 @@
 //! As explained in [`crate::usefulness`], values and patterns are made from constructors applied to
 //! fields. This file defines types that represent patterns in this way.
+
 use std::fmt;
 
 use smallvec::{smallvec, SmallVec};

compiler/rustc_pattern_analysis/tests/complexity.rs

@@ -1,4 +1,5 @@
 //! Test the pattern complexity limit.
+
 use common::*;
 use rustc_pattern_analysis::{pat::DeconstructedPat, usefulness::PlaceValidity, MatchArm};
 

compiler/rustc_pattern_analysis/tests/exhaustiveness.rs

@@ -1,4 +1,5 @@
 //! Test exhaustiveness checking.
+
 use common::*;
 use rustc_pattern_analysis::{
     pat::{DeconstructedPat, WitnessPat},

compiler/rustc_pattern_analysis/tests/intersection.rs

@@ -1,4 +1,5 @@
 //! Test the computation of arm intersections.
+
 use common::*;
 use rustc_pattern_analysis::{pat::DeconstructedPat, usefulness::PlaceValidity, MatchArm};
 

compiler/rustc_sanitizers/src/cfi/typeid/itanium_cxx_abi/encode.rs

@@ -4,6 +4,7 @@
 //!
 //! For more information about LLVM CFI and cross-language LLVM CFI support for the Rust compiler,
 //! see design document in the tracking issue #89653.
+
 use rustc_data_structures::base_n::ToBaseN;
 use rustc_data_structures::base_n::ALPHANUMERIC_ONLY;
 use rustc_data_structures::base_n::CASE_INSENSITIVE;

compiler/rustc_sanitizers/src/cfi/typeid/itanium_cxx_abi/mod.rs

@@ -3,6 +3,7 @@
 //!
 //! For more information about LLVM CFI and cross-language LLVM CFI support for the Rust compiler,
 //! see design document in the tracking issue #89653.
+
 use rustc_data_structures::fx::FxHashMap;
 use rustc_middle::bug;
 use rustc_middle::ty::{self, Instance, Ty, TyCtxt, TypeFoldable};

compiler/rustc_sanitizers/src/cfi/typeid/itanium_cxx_abi/transform.rs

@@ -3,6 +3,7 @@
 //!
 //! For more information about LLVM CFI and cross-language LLVM CFI support for the Rust compiler,
 //! see design document in the tracking issue #89653.
+
 use rustc_hir as hir;
 use rustc_hir::LangItem;
 use rustc_middle::bug;

compiler/rustc_sanitizers/src/cfi/typeid/mod.rs

@@ -3,6 +3,7 @@
 //!
 //! For more information about LLVM CFI and cross-language LLVM CFI support for the Rust compiler,
 //! see design document in the tracking issue #89653.
+
 use bitflags::bitflags;
 use rustc_middle::ty::{Instance, Ty, TyCtxt};
 use rustc_target::abi::call::FnAbi;

compiler/rustc_sanitizers/src/kcfi/typeid/mod.rs

@@ -3,6 +3,7 @@
 //!
 //! For more information about LLVM KCFI and cross-language LLVM KCFI support for the Rust compiler,
 //! see the tracking issue #123479.
+
 use rustc_middle::ty::{Instance, InstanceKind, ReifyReason, Ty, TyCtxt};
 use rustc_target::abi::call::FnAbi;
 use std::hash::Hasher;

compiler/rustc_session/src/output.rs

@@ -1,4 +1,5 @@
 //! Related to out filenames of compilation (e.g. binaries).
+
 use crate::config::{self, CrateType, Input, OutFileName, OutputFilenames, OutputType};
 use crate::errors::{
     self, CrateNameDoesNotMatch, CrateNameEmpty, CrateNameInvalid, FileIsNotWriteable,

compiler/rustc_smir/src/rustc_smir/builder.rs

@@ -3,6 +3,7 @@
 //! We first retrieve and monomorphize the rustc body representation, i.e., we generate a
 //! monomorphic body using internal representation.
 //! After that, we convert the internal representation into a stable one.
+
 use crate::rustc_smir::{Stable, Tables};
 use rustc_hir::def::DefKind;
 use rustc_middle::mir;

compiler/rustc_smir/src/rustc_smir/convert/error.rs

@@ -1,6 +1,7 @@
 //! Handle the conversion of different internal errors into a stable version.
 //!
 //! Currently we encode everything as [stable_mir::Error], which is represented as a string.
+
 use crate::rustc_smir::{Stable, Tables};
 use rustc_middle::mir::interpret::AllocError;
 use rustc_middle::ty::layout::LayoutError;

compiler/rustc_target/src/spec/mod.rs

@@ -1768,8 +1768,11 @@ supported_targets! {
     ("nvptx64-nvidia-cuda", nvptx64_nvidia_cuda),
 
     ("xtensa-esp32-none-elf", xtensa_esp32_none_elf),
+    ("xtensa-esp32-espidf", xtensa_esp32_espidf),
     ("xtensa-esp32s2-none-elf", xtensa_esp32s2_none_elf),
+    ("xtensa-esp32s2-espidf", xtensa_esp32s2_espidf),
     ("xtensa-esp32s3-none-elf", xtensa_esp32s3_none_elf),
+    ("xtensa-esp32s3-espidf", xtensa_esp32s3_espidf),
 
     ("i686-wrs-vxworks", i686_wrs_vxworks),
     ("x86_64-wrs-vxworks", x86_64_wrs_vxworks),

compiler/rustc_target/src/spec/targets/mips64_openwrt_linux_musl.rs

@@ -1,5 +1,5 @@
-/// A target tuple for OpenWrt MIPS64 targets
-///
+//! A target tuple for OpenWrt MIPS64 targets.
+
 use crate::abi::Endian;
 use crate::spec::{base, Target, TargetOptions};
 

compiler/rustc_target/src/spec/targets/xtensa_esp32_espidf.rs

@@ -0,0 +1,36 @@
+use crate::abi::Endian;
+use crate::spec::{base::xtensa, cvs, Target, TargetOptions};
+
+pub fn target() -> Target {
+    Target {
+        llvm_target: "xtensa-none-elf".into(),
+        pointer_width: 32,
+        data_layout: "e-m:e-p:32:32-v1:8:8-i64:64-i128:128-n32".into(),
+        arch: "xtensa".into(),
+        metadata: crate::spec::TargetMetadata {
+            description: None,
+            tier: None,
+            host_tools: None,
+            std: None,
+        },
+
+        options: TargetOptions {
+            endian: Endian::Little,
+            c_int_width: "32".into(),
+            families: cvs!["unix"],
+            os: "espidf".into(),
+            env: "newlib".into(),
+            vendor: "espressif".into(),
+
+            executables: true,
+            cpu: "esp32".into(),
+            linker: Some("xtensa-esp32-elf-gcc".into()),
+
+            // The esp32 only supports native 32bit atomics.
+            max_atomic_width: Some(32),
+            atomic_cas: true,
+
+            ..xtensa::opts()
+        },
+    }
+}

compiler/rustc_target/src/spec/targets/xtensa_esp32s2_espidf.rs

@@ -0,0 +1,43 @@
+use crate::abi::Endian;
+use crate::spec::{base::xtensa, cvs, Target, TargetOptions};
+
+pub fn target() -> Target {
+    Target {
+        llvm_target: "xtensa-none-elf".into(),
+        pointer_width: 32,
+        data_layout: "e-m:e-p:32:32-v1:8:8-i64:64-i128:128-n32".into(),
+        arch: "xtensa".into(),
+        metadata: crate::spec::TargetMetadata {
+            description: None,
+            tier: None,
+            host_tools: None,
+            std: None,
+        },
+
+        options: TargetOptions {
+            endian: Endian::Little,
+            c_int_width: "32".into(),
+            families: cvs!["unix"],
+            os: "espidf".into(),
+            env: "newlib".into(),
+            vendor: "espressif".into(),
+
+            executables: true,
+            cpu: "esp32-s2".into(),
+            linker: Some("xtensa-esp32s2-elf-gcc".into()),
+
+            // See https://github.com/espressif/rust-esp32-example/issues/3#issuecomment-861054477
+            //
+            // While the ESP32-S2 chip does not natively support atomics, ESP-IDF does support
+            // the __atomic* and __sync* compiler builtins. Setting `max_atomic_width` and `atomic_cas`
+            // and `atomic_cas: true` will cause the compiler to emit libcalls to these builtins. On the
+            // ESP32-S2, these are guaranteed to be lock-free.
+            //
+            // Support for atomics is necessary for the Rust STD library, which is supported by ESP-IDF.
+            max_atomic_width: Some(32),
+            atomic_cas: true,
+
+            ..xtensa::opts()
+        },
+    }
+}

compiler/rustc_target/src/spec/targets/xtensa_esp32s3_espidf.rs

@@ -0,0 +1,36 @@
+use crate::abi::Endian;
+use crate::spec::{base::xtensa, cvs, Target, TargetOptions};
+
+pub fn target() -> Target {
+    Target {
+        llvm_target: "xtensa-none-elf".into(),
+        pointer_width: 32,
+        data_layout: "e-m:e-p:32:32-v1:8:8-i64:64-i128:128-n32".into(),
+        arch: "xtensa".into(),
+        metadata: crate::spec::TargetMetadata {
+            description: None,
+            tier: None,
+            host_tools: None,
+            std: None,
+        },
+
+        options: TargetOptions {
+            endian: Endian::Little,
+            c_int_width: "32".into(),
+            families: cvs!["unix"],
+            os: "espidf".into(),
+            env: "newlib".into(),
+            vendor: "espressif".into(),
+
+            executables: true,
+            cpu: "esp32-s3".into(),
+            linker: Some("xtensa-esp32s3-elf-gcc".into()),
+
+            // The esp32s3 only supports native 32bit atomics.
+            max_atomic_width: Some(32),
+            atomic_cas: true,
+
+            ..xtensa::opts()
+        },
+    }
+}

compiler/rustc_trait_selection/src/traits/normalize.rs

@@ -1,4 +1,5 @@
 //! Deeply normalize types using the old trait solver.
+
 use super::error_reporting::OverflowCause;
 use super::error_reporting::TypeErrCtxtExt;
 use super::SelectionContext;

compiler/rustc_trait_selection/src/traits/select/confirmation.rs

@@ -6,6 +6,7 @@
 //!
 //! [rustc dev guide]:
 //! https://rustc-dev-guide.rust-lang.org/traits/resolution.html#confirmation
+
 use rustc_ast::Mutability;
 use rustc_data_structures::stack::ensure_sufficient_stack;
 use rustc_hir::lang_items::LangItem;

compiler/stable_mir/src/mir/alloc.rs

@@ -1,4 +1,5 @@
 //! This module provides methods to retrieve allocation information, such as static variables.
+
 use crate::mir::mono::{Instance, StaticDef};
 use crate::target::{Endian, MachineInfo};
 use crate::ty::{Allocation, Binder, ExistentialTraitRef, IndexedVal, Ty};