diff --git a/base/compiler/ssair/inlining.jl b/base/compiler/ssair/inlining.jl
index 0519f0012ec6c9..5ddce03f5dadf6 100644
--- a/base/compiler/ssair/inlining.jl
+++ b/base/compiler/ssair/inlining.jl
@@ -905,10 +905,12 @@ function resolve_todo(mi::MethodInstance, result::Union{MethodMatch,InferenceRes
     if src isa String && inferred_result !== nothing
         # if the inferred source for this globally-cached method is available,
         # use it destructively as it will never be used again
-        ir = inflate_ir!(inferred_result.inferred_src, mi)
+        src = inferred_result.inferred_src
+        preserve_local_sources = OptimizationParams(state.interp).preserve_local_sources
     else
-        ir = retrieve_ir_for_inlining(mi, src)
+        preserve_local_sources = true
     end
+    ir = retrieve_ir_for_inlining(mi, src, preserve_local_sources)
 
     return InliningTodo(mi, ir, effects)
 end
@@ -987,12 +989,22 @@ function analyze_method!(match::MethodMatch, argtypes::Vector{Any},
     return resolve_todo(mi, match, argtypes, info, flag, state; invokesig, inferred_result)
 end
 
-function retrieve_ir_for_inlining(mi::MethodInstance, src::String)
+function retrieve_ir_for_inlining(mi::MethodInstance, src::String, ::Bool=true)
     src = ccall(:jl_uncompress_ir, Any, (Any, Ptr{Cvoid}, Any), mi.def, C_NULL, src)::CodeInfo
     return inflate_ir!(src, mi)
 end
-retrieve_ir_for_inlining(mi::MethodInstance, src::CodeInfo) = inflate_ir(src, mi)
-retrieve_ir_for_inlining(mi::MethodInstance, ir::IRCode) = copy(ir)
+function retrieve_ir_for_inlining(mi::MethodInstance, src::CodeInfo, preserve_local_sources::Bool=true)
+    if preserve_local_sources
+        src = copy(src)
+    end
+    return inflate_ir!(src, mi)
+end
+function retrieve_ir_for_inlining(::MethodInstance, ir::IRCode, preserve_local_sources::Bool=true)
+    if preserve_local_sources
+        ir = copy(ir)
+    end
+    return ir
+end
 
 function flags_for_effects(effects::Effects)
     flags::UInt32 = 0
@@ -1524,7 +1536,9 @@ function semiconcrete_result_item(result::SemiConcreteResult,
         return compileable_specialization(mi, result.effects, et, info;
             compilesig_invokes=OptimizationParams(state.interp).compilesig_invokes)
     else
-        return InliningTodo(mi, retrieve_ir_for_inlining(mi, result.ir), result.effects)
+        preserve_local_sources = OptimizationParams(state.interp).preserve_local_sources
+        ir = retrieve_ir_for_inlining(mi, result.ir, preserve_local_sources)
+        return InliningTodo(mi, ir, result.effects)
     end
 end
 
diff --git a/base/compiler/types.jl b/base/compiler/types.jl
index c53256c61ace94..ba05131d4e3a3a 100644
--- a/base/compiler/types.jl
+++ b/base/compiler/types.jl
@@ -253,6 +253,11 @@ Parameters that control optimizer operation.
   optimizer license to move side effects (that are proven not observed within a particular
   code path) across a throwing call. Defaults to `false`.
 ---
+- `opt_params.preserve_local_sources::Bool = false`\\
+  If `true`, the inliner is restricted from modifying locally-cached sources that are
+  retained in `CallInfo` objects and always makes their copies before inlining them into
+  caller context. Defaults to `false`.
+---
 """
 struct OptimizationParams
     inlining::Bool
@@ -263,6 +268,7 @@ struct OptimizationParams
     max_tuple_splat::Int
     compilesig_invokes::Bool
     assume_fatal_throw::Bool
+    preserve_local_sources::Bool
 
     function OptimizationParams(
         inlining::Bool,
@@ -272,7 +278,8 @@ struct OptimizationParams
         inline_error_path_cost::Int,
         max_tuple_splat::Int,
         compilesig_invokes::Bool,
-        assume_fatal_throw::Bool)
+        assume_fatal_throw::Bool,
+        preserve_local_sources::Bool)
         return new(
             inlining,
             inline_cost_threshold,
@@ -281,7 +288,8 @@ struct OptimizationParams
             inline_error_path_cost,
             max_tuple_splat,
             compilesig_invokes,
-            assume_fatal_throw)
+            assume_fatal_throw,
+            preserve_local_sources)
     end
 end
 function OptimizationParams(
@@ -293,7 +301,8 @@ function OptimizationParams(
         #=inline_error_path_cost::Int=# 20,
         #=max_tuple_splat::Int=# 32,
         #=compilesig_invokes::Bool=# true,
-        #=assume_fatal_throw::Bool=# false);
+        #=assume_fatal_throw::Bool=# false,
+        #=preserve_local_sources::Bool=# false);
     inlining::Bool = params.inlining,
     inline_cost_threshold::Int = params.inline_cost_threshold,
     inline_nonleaf_penalty::Int = params.inline_nonleaf_penalty,
@@ -301,7 +310,8 @@ function OptimizationParams(
     inline_error_path_cost::Int = params.inline_error_path_cost,
     max_tuple_splat::Int = params.max_tuple_splat,
     compilesig_invokes::Bool = params.compilesig_invokes,
-    assume_fatal_throw::Bool = params.assume_fatal_throw)
+    assume_fatal_throw::Bool = params.assume_fatal_throw,
+    preserve_local_sources::Bool = params.preserve_local_sources)
     return OptimizationParams(
         inlining,
         inline_cost_threshold,
@@ -310,7 +320,8 @@ function OptimizationParams(
         inline_error_path_cost,
         max_tuple_splat,
         compilesig_invokes,
-        assume_fatal_throw)
+        assume_fatal_throw,
+        preserve_local_sources)
 end
 
 """