Sema: `@memcpy` convert src slice to many ptr

Closes #15838

2 files changed, 6 insertions, 1 deletions

diff --git a/src/Sema.zig b/src/Sema.zig
index 76c9891467..1ee19515aa 100644
--- a/src/Sema.zig
+++ b/src/Sema.zig
@@ -22235,6 +22235,10 @@ fn zirMemcpy(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!void
         // Change the dest to a slice, since its type must have the length.
         const dest_ptr_ptr = try sema.analyzeRef(block, dest_src, new_dest_ptr);
         new_dest_ptr = try sema.analyzeSlice(block, dest_src, dest_ptr_ptr, .zero, src_len, .none, .unneeded, dest_src, dest_src, dest_src, false);
+        const new_src_ptr_ty = sema.typeOf(new_src_ptr);
+        if (new_src_ptr_ty.isSlice()) {
+            new_src_ptr = try sema.analyzeSlicePtr(block, src_src, new_src_ptr, new_src_ptr_ty);
+        }
     }
 
     try sema.requireRuntimeBlock(block, src, runtime_src);
diff --git a/test/behavior/memcpy.zig b/test/behavior/memcpy.zig
index b7c5eb29d9..3a87b66fb1 100644
--- a/test/behavior/memcpy.zig
+++ b/test/behavior/memcpy.zig
@@ -58,7 +58,8 @@ test "@memcpy dest many pointer" {
 fn testMemcpyDestManyPtr() !void {
     var str = "hello".*;
     var buf: [5]u8 = undefined;
-    @memcpy(@ptrCast([*]u8, &buf), @ptrCast([*]const u8, &str)[0..5]);
+    var len: usize = 5;
+    @memcpy(@ptrCast([*]u8, &buf), @ptrCast([*]const u8, &str)[0..len]);
     try expect(buf[0] == 'h');
     try expect(buf[1] == 'e');
     try expect(buf[2] == 'l');