Auto merge of #10478 - Jarcho:block_eq, r=xFrednet

`SpanlessEq` improvements

fixes #9775

Also includes a simplification to `consts::constant`'s interface since I was already touching the code.

At the start of `eq_expr` the check:
```rust
if !self.inner.allow_side_effects && left.span.ctxt() != right.span.ctxt() {
    return false;
}
```
was removed. This was added in 49e2501 to handle `cfg` macros. This is better handled by the newly added `check_ctxt`.

changelog: [various lints]: Don't consider different `cfg!` expansions to be the same unless they are for the same config.
changelog: [various lints]: Don't consider the expansion of two different macros to be equal, even when they expand to the same token sequence.
changelog: [various lints]: Don't consider two blocks to be equal if they contain disabled code or empty macro expansions, unless those section contain the exact same token sequence.

Author: bors

clippy_lints/src/assertions_on_constants.rs

@@ -38,7 +38,7 @@ impl<'tcx> LateLintPass<'tcx> for AssertionsOnConstants {
             _ => return,
         };
         let Some((condition, panic_expn)) = find_assert_args(cx, e, macro_call.expn) else { return };
-        let Some((Constant::Bool(val), _)) = constant(cx, cx.typeck_results(), condition) else { return };
+        let Some(Constant::Bool(val)) = constant(cx, cx.typeck_results(), condition) else { return };
         if val {
             span_lint_and_help(
                 cx,

clippy_lints/src/casts/cast_nan_to_int.rs

@@ -21,8 +21,8 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, cast_expr: &Expr<'_>,
 
 fn is_known_nan(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
     match constant(cx, cx.typeck_results(), e) {
-        Some((Constant::F64(n), _)) => n.is_nan(),
-        Some((Constant::F32(n), _)) => n.is_nan(),
+        Some(Constant::F64(n)) => n.is_nan(),
+        Some(Constant::F32(n)) => n.is_nan(),
         _ => false,
     }
 }

clippy_lints/src/casts/cast_possible_truncation.rs

@@ -15,7 +15,7 @@ use rustc_target::abi::IntegerType;
 use super::{utils, CAST_ENUM_TRUNCATION, CAST_POSSIBLE_TRUNCATION};
 
 fn constant_int(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<u128> {
-    if let Some((Constant::Int(c), _)) = constant(cx, cx.typeck_results(), expr) {
+    if let Some(Constant::Int(c)) = constant(cx, cx.typeck_results(), expr) {
         Some(c)
     } else {
         None

clippy_lints/src/casts/cast_sign_loss.rs

@@ -29,7 +29,7 @@ fn should_lint(cx: &LateContext<'_>, cast_op: &Expr<'_>, cast_from: Ty<'_>, cast
             // Don't lint for positive constants.
             let const_val = constant(cx, cx.typeck_results(), cast_op);
             if_chain! {
-                if let Some((Constant::Int(n), _)) = const_val;
+                if let Some(Constant::Int(n)) = const_val;
                 if let ty::Int(ity) = *cast_from.kind();
                 if sext(cx.tcx, n, ity) >= 0;
                 then {

clippy_lints/src/floating_point_arithmetic.rs

@@ -114,7 +114,7 @@ declare_lint_pass!(FloatingPointArithmetic => [
 // Returns the specialized log method for a given base if base is constant
 // and is one of 2, 10 and e
 fn get_specialized_log_method(cx: &LateContext<'_>, base: &Expr<'_>) -> Option<&'static str> {
-    if let Some((value, _)) = constant(cx, cx.typeck_results(), base) {
+    if let Some(value) = constant(cx, cx.typeck_results(), base) {
         if F32(2.0) == value || F64(2.0) == value {
             return Some("log2");
         } else if F32(10.0) == value || F64(10.0) == value {
@@ -193,8 +193,8 @@ fn check_ln1p(cx: &LateContext<'_>, expr: &Expr<'_>, receiver: &Expr<'_>) {
             constant(cx, cx.typeck_results(), lhs),
             constant(cx, cx.typeck_results(), rhs),
         ) {
-            (Some((value, _)), _) if F32(1.0) == value || F64(1.0) == value => rhs,
-            (_, Some((value, _))) if F32(1.0) == value || F64(1.0) == value => lhs,
+            (Some(value), _) if F32(1.0) == value || F64(1.0) == value => rhs,
+            (_, Some(value)) if F32(1.0) == value || F64(1.0) == value => lhs,
             _ => return,
         };
 
@@ -237,7 +237,7 @@ fn get_integer_from_float_constant(value: &Constant) -> Option<i32> {
 
 fn check_powf(cx: &LateContext<'_>, expr: &Expr<'_>, receiver: &Expr<'_>, args: &[Expr<'_>]) {
     // Check receiver
-    if let Some((value, _)) = constant(cx, cx.typeck_results(), receiver) {
+    if let Some(value) = constant(cx, cx.typeck_results(), receiver) {
         if let Some(method) = if F32(f32_consts::E) == value || F64(f64_consts::E) == value {
             Some("exp")
         } else if F32(2.0) == value || F64(2.0) == value {
@@ -258,7 +258,7 @@ fn check_powf(cx: &LateContext<'_>, expr: &Expr<'_>, receiver: &Expr<'_>, args:
     }
 
     // Check argument
-    if let Some((value, _)) = constant(cx, cx.typeck_results(), &args[0]) {
+    if let Some(value) = constant(cx, cx.typeck_results(), &args[0]) {
         let (lint, help, suggestion) = if F32(1.0 / 2.0) == value || F64(1.0 / 2.0) == value {
             (
                 SUBOPTIMAL_FLOPS,
@@ -298,7 +298,7 @@ fn check_powf(cx: &LateContext<'_>, expr: &Expr<'_>, receiver: &Expr<'_>, args:
 }
 
 fn check_powi(cx: &LateContext<'_>, expr: &Expr<'_>, receiver: &Expr<'_>, args: &[Expr<'_>]) {
-    if let Some((value, _)) = constant(cx, cx.typeck_results(), &args[0]) {
+    if let Some(value) = constant(cx, cx.typeck_results(), &args[0]) {
         if value == Int(2) {
             if let Some(parent) = get_parent_expr(cx, expr) {
                 if let Some(grandparent) = get_parent_expr(cx, parent) {
@@ -384,8 +384,8 @@ fn detect_hypot(cx: &LateContext<'_>, receiver: &Expr<'_>) -> Option<String> {
                 _
             ) = &add_rhs.kind;
             if lmethod_name.as_str() == "powi" && rmethod_name.as_str() == "powi";
-            if let Some((lvalue, _)) = constant(cx, cx.typeck_results(), largs_1);
-            if let Some((rvalue, _)) = constant(cx, cx.typeck_results(), rargs_1);
+            if let Some(lvalue) = constant(cx, cx.typeck_results(), largs_1);
+            if let Some(rvalue) = constant(cx, cx.typeck_results(), rargs_1);
             if Int(2) == lvalue && Int(2) == rvalue;
             then {
                 return Some(format!("{}.hypot({})", Sugg::hir(cx, largs_0, "..").maybe_par(), Sugg::hir(cx, rargs_0, "..")));
@@ -416,7 +416,7 @@ fn check_expm1(cx: &LateContext<'_>, expr: &Expr<'_>) {
     if_chain! {
         if let ExprKind::Binary(Spanned { node: BinOpKind::Sub, .. }, lhs, rhs) = expr.kind;
         if cx.typeck_results().expr_ty(lhs).is_floating_point();
-        if let Some((value, _)) = constant(cx, cx.typeck_results(), rhs);
+        if let Some(value) = constant(cx, cx.typeck_results(), rhs);
         if F32(1.0) == value || F64(1.0) == value;
         if let ExprKind::MethodCall(path, self_arg, ..) = &lhs.kind;
         if cx.typeck_results().expr_ty(self_arg).is_floating_point();
@@ -669,8 +669,8 @@ fn check_radians(cx: &LateContext<'_>, expr: &Expr<'_>) {
             mul_lhs,
             mul_rhs,
         ) = &div_lhs.kind;
-        if let Some((rvalue, _)) = constant(cx, cx.typeck_results(), div_rhs);
-        if let Some((lvalue, _)) = constant(cx, cx.typeck_results(), mul_rhs);
+        if let Some(rvalue) = constant(cx, cx.typeck_results(), div_rhs);
+        if let Some(lvalue) = constant(cx, cx.typeck_results(), mul_rhs);
         then {
             // TODO: also check for constant values near PI/180 or 180/PI
             if (F32(f32_consts::PI) == rvalue || F64(f64_consts::PI) == rvalue) &&

clippy_lints/src/fn_null_check.rs

@@ -89,11 +89,7 @@ impl<'tcx> LateLintPass<'tcx> for FnNullCheck {
 
                     // Catching:
                     // (fn_ptr as *<const/mut> <ty>) == <const that evaluates to null_ptr>
-                    _ if matches!(
-                        constant(cx, cx.typeck_results(), to_check),
-                        Some((Constant::RawPtr(0), _))
-                    ) =>
-                    {
+                    _ if matches!(constant(cx, cx.typeck_results(), to_check), Some(Constant::RawPtr(0))) => {
                         lint_expr(cx, expr);
                     },
 

clippy_lints/src/implicit_saturating_add.rs

@@ -101,10 +101,10 @@ fn get_int_max(ty: Ty<'_>) -> Option<u128> {
 fn get_const<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'tcx>) -> Option<(u128, BinOpKind, &'tcx Expr<'tcx>)> {
     if let ExprKind::Binary(op, l, r) = expr.kind {
         let tr = cx.typeck_results();
-        if let Some((Constant::Int(c), _)) = constant(cx, tr, r) {
+        if let Some(Constant::Int(c)) = constant(cx, tr, r) {
             return Some((c, op.node, l));
         };
-        if let Some((Constant::Int(c), _)) = constant(cx, tr, l) {
+        if let Some(Constant::Int(c)) = constant(cx, tr, l) {
             return Some((c, invert_op(op.node)?, r));
         }
     }

clippy_lints/src/index_refutable_slice.rs

@@ -254,7 +254,7 @@ impl<'a, 'tcx> Visitor<'tcx> for SliceIndexLintingVisitor<'a, 'tcx> {
                 let parent_id = map.parent_id(expr.hir_id);
                 if let Some(hir::Node::Expr(parent_expr)) = map.find(parent_id);
                 if let hir::ExprKind::Index(_, index_expr) = parent_expr.kind;
-                if let Some((Constant::Int(index_value), _)) = constant(cx, cx.typeck_results(), index_expr);
+                if let Some(Constant::Int(index_value)) = constant(cx, cx.typeck_results(), index_expr);
                 if let Ok(index_value) = index_value.try_into();
                 if index_value < max_suggested_slice;
 

clippy_lints/src/indexing_slicing.rs

@@ -191,18 +191,14 @@ impl<'tcx> LateLintPass<'tcx> for IndexingSlicing {
 /// Returns a tuple of options with the start and end (exclusive) values of
 /// the range. If the start or end is not constant, None is returned.
 fn to_const_range(cx: &LateContext<'_>, range: higher::Range<'_>, array_size: u128) -> (Option<u128>, Option<u128>) {
-    let s = range
-        .start
-        .map(|expr| constant(cx, cx.typeck_results(), expr).map(|(c, _)| c));
+    let s = range.start.map(|expr| constant(cx, cx.typeck_results(), expr));
     let start = match s {
         Some(Some(Constant::Int(x))) => Some(x),
         Some(_) => None,
         None => Some(0),
     };
 
-    let e = range
-        .end
-        .map(|expr| constant(cx, cx.typeck_results(), expr).map(|(c, _)| c));
+    let e = range.end.map(|expr| constant(cx, cx.typeck_results(), expr));
     let end = match e {
         Some(Some(Constant::Int(x))) => {
             if range.limits == RangeLimits::Closed {

clippy_lints/src/manual_strip.rs

@@ -144,7 +144,7 @@ fn len_arg<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<&'tcx E
 
 // Returns the length of the `expr` if it's a constant string or char.
 fn constant_length(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<u128> {
-    let (value, _) = constant(cx, cx.typeck_results(), expr)?;
+    let value = constant(cx, cx.typeck_results(), expr)?;
     match value {
         Constant::Str(value) => Some(value.len() as u128),
         Constant::Char(value) => Some(value.len_utf8() as u128),