WIP fix inlining spans

Author: jsgf

compiler/rustc_mir_transform/src/annotate_moves.rs

@@ -233,12 +233,19 @@ impl AnnotateMoves {
             original_source_info.span,
         );
 
+        // Get the span of the intrinsic function definition - this represents
+        // "where we are inside the inlined function"
+        let intrinsic_span = tcx.def_span(intrinsic_def_id);
+
         // Create new inlined scope that makes the operation appear to come from the intrinsic
         let inlined_scope_data = SourceScopeData {
-            span: original_source_info.span,
+            // Use the intrinsic's definition span to show where we are "inside" the inlined function
+            span: intrinsic_span,
             parent_scope: Some(original_source_info.scope),
 
-            // Pretend this op is inlined from the intrinsic
+            // The inlined field shows: (what was inlined, where it was called from)
+            // - intrinsic_instance: the compiler_move/copy function that was "inlined"
+            // - original_source_info.span: the call site (where the actual move/copy is)
             inlined: Some((intrinsic_instance, original_source_info.span)),
 
             // Proper inlined scope chaining to maintain debug info hierarchy