diff --git a/cranelift/codegen/src/machinst/vcode.rs b/cranelift/codegen/src/machinst/vcode.rs
index 6b77411d3c..fe1678db63 100644
--- a/cranelift/codegen/src/machinst/vcode.rs
+++ b/cranelift/codegen/src/machinst/vcode.rs
@@ -550,7 +550,7 @@ impl<I: VCodeInst> VCode<I> {
         let code_section = sections.get_section(code_idx);
 
         let flags = self.abi.flags();
-        let mut cur_srcloc = SourceLoc::default();
+        let mut cur_srcloc = None;
         for &block in &self.final_block_order {
             let new_offset = I::align_basic_block(code_section.cur_offset_from_start());
             while new_offset > code_section.cur_offset_from_start() {
@@ -563,22 +563,20 @@ impl<I: VCodeInst> VCode<I> {
             let (start, end) = self.block_ranges[block as usize];
             for iix in start..end {
                 let srcloc = self.srclocs[iix as usize];
-                if srcloc != cur_srcloc {
-                    if !cur_srcloc.is_default() {
+                if cur_srcloc != Some(srcloc) {
+                    if cur_srcloc.is_some() {
                         code_section.end_srcloc();
                     }
-                    if !srcloc.is_default() {
-                        code_section.start_srcloc(srcloc);
-                    }
-                    cur_srcloc = srcloc;
+                    code_section.start_srcloc(srcloc);
+                    cur_srcloc = Some(srcloc);
                 }
 
                 self.insts[iix as usize].emit(code_section, flags);
             }
 
-            if !cur_srcloc.is_default() {
+            if cur_srcloc.is_some() {
                 code_section.end_srcloc();
-                cur_srcloc = SourceLoc::default();
+                cur_srcloc = None;
             }
         }
 
diff --git a/crates/api/src/frame_info.rs b/crates/api/src/frame_info.rs
index 7894e36945..0a4b2b6cf6 100644
--- a/crates/api/src/frame_info.rs
+++ b/crates/api/src/frame_info.rs
@@ -94,11 +94,7 @@ impl GlobalFrameInfo {
         // the function, because otherwise something is buggy along the way and
         // not accounting for all the instructions. This isn't super critical
         // though so we can omit this check in release mode.
-        //
-        // FIXME(#1521) aarch64 instruction info isn't quite up-to-par yet.
-        if !cfg!(target_arch = "aarch64") {
-            debug_assert!(pos.is_some(), "failed to find instruction for {:x}", pc);
-        }
+        debug_assert!(pos.is_some(), "failed to find instruction for {:x}", pc);
 
         let instr = match pos {
             Some(pos) => func.instr_map.instructions[pos].srcloc,