Use a not working type param default instead of cfg-gating

cfg-gating type params only work in Rust 1.48+

src/read/cfi.rs

@@ -11,9 +11,9 @@ use super::util::{ArrayLike, ArrayVec};
 use crate::common::{DebugFrameOffset, EhFrameOffset, Encoding, Format, Register, SectionId};
 use crate::constants::{self, DwEhPe};
 use crate::endianity::Endianity;
-#[cfg(feature = "read")]
-use crate::read::StoreOnHeap;
-use crate::read::{EndianSlice, Error, Expression, Reader, ReaderOffset, Result, Section};
+use crate::read::{
+    EndianSlice, Error, Expression, Reader, ReaderOffset, Result, Section, StoreOnHeap,
+};
 
 /// `DebugFrame` contains the `.debug_frame` section's frame unwinding
 /// information required to unwind to and recover registers from older frames on
@@ -1822,11 +1822,7 @@ impl<R: Reader> UnwindContextStorage<R> for StoreOnHeap {
 /// # }
 /// ```
 #[derive(Clone, PartialEq, Eq)]
-pub struct UnwindContext<
-    R: Reader,
-    #[cfg(not(feature = "read"))] A: UnwindContextStorage<R>,
-    #[cfg(feature = "read")] A: UnwindContextStorage<R> = StoreOnHeap,
-> {
+pub struct UnwindContext<R: Reader, A: UnwindContextStorage<R> = StoreOnHeap> {
     // Stack of rows. The last row is the row currently being built by the
     // program. There is always at least one row. The vast majority of CFI
     // programs will only ever have one row on the stack.
@@ -2049,13 +2045,7 @@ impl<R: Reader, A: UnwindContextStorage<R>> UnwindContext<R, A> {
 /// > recording just the differences starting at the beginning address of each
 /// > subroutine in the program.
 #[derive(Debug)]
-pub struct UnwindTable<
-    'a,
-    'ctx,
-    R: Reader,
-    #[cfg(not(feature = "read"))] A: UnwindContextStorage<R>,
-    #[cfg(feature = "read")] A: UnwindContextStorage<R> = StoreOnHeap,
-> {
+pub struct UnwindTable<'a, 'ctx, R: Reader, A: UnwindContextStorage<R> = StoreOnHeap> {
     code_alignment_factor: Wrapping<u64>,
     data_alignment_factor: Wrapping<i64>,
     next_start_address: u64,
@@ -2366,11 +2356,7 @@ impl<'a, 'ctx, R: Reader, A: UnwindContextStorage<R>> UnwindTable<'a, 'ctx, R, A
 // - https://github.com/libunwind/libunwind/blob/11fd461095ea98f4b3e3a361f5a8a558519363fa/include/tdep-aarch64/dwarf-config.h#L32
 // - https://github.com/libunwind/libunwind/blob/11fd461095ea98f4b3e3a361f5a8a558519363fa/include/tdep-arm/dwarf-config.h#L31
 // - https://github.com/libunwind/libunwind/blob/11fd461095ea98f4b3e3a361f5a8a558519363fa/include/tdep-mips/dwarf-config.h#L31
-struct RegisterRuleMap<
-    R: Reader,
-    #[cfg(not(feature = "read"))] S: UnwindContextStorage<R>,
-    #[cfg(feature = "read")] S: UnwindContextStorage<R> = StoreOnHeap,
-> {
+struct RegisterRuleMap<R: Reader, S: UnwindContextStorage<R> = StoreOnHeap> {
     rules: ArrayVec<S::Rules>,
 }
 
@@ -2513,11 +2499,7 @@ impl<'iter, R: Reader> Iterator for RegisterRuleIter<'iter, R> {
 /// A row in the virtual unwind table that describes how to find the values of
 /// the registers in the *previous* frame for a range of PC addresses.
 #[derive(PartialEq, Eq)]
-pub struct UnwindTableRow<
-    R: Reader,
-    #[cfg(not(feature = "read"))] S: UnwindContextStorage<R>,
-    #[cfg(feature = "read")] S: UnwindContextStorage<R> = StoreOnHeap,
-> {
+pub struct UnwindTableRow<R: Reader, S: UnwindContextStorage<R> = StoreOnHeap> {
     start_address: u64,
     end_address: u64,
     saved_args_size: u64,

src/read/op.rs

@@ -7,9 +7,7 @@ use core::mem;
 use super::util::{ArrayLike, ArrayVec};
 use crate::common::{DebugAddrIndex, DebugInfoOffset, Encoding, Register};
 use crate::constants;
-#[cfg(feature = "read")]
-use crate::read::StoreOnHeap;
-use crate::read::{Error, Reader, ReaderOffset, Result, UnitOffset, Value, ValueType};
+use crate::read::{Error, Reader, ReaderOffset, Result, StoreOnHeap, UnitOffset, Value, ValueType};
 
 /// A reference to a DIE, either relative to the current CU or
 /// relative to the section.
@@ -1092,11 +1090,7 @@ impl<R: Reader> EvaluationStorage<R> for StoreOnHeap {
 /// println!("{:?}", result);
 /// ```
 #[derive(Debug)]
-pub struct Evaluation<
-    R: Reader,
-    #[cfg(not(feature = "read"))] S: EvaluationStorage<R>,
-    #[cfg(feature = "read")] S: EvaluationStorage<R> = StoreOnHeap,
-> {
+pub struct Evaluation<R: Reader, S: EvaluationStorage<R> = StoreOnHeap> {
     bytecode: R,
     encoding: Encoding,
     object_address: Option<u64>,