From 34d44e0c1c2cdfc5916dd5c56914f181f87e8d85 Mon Sep 17 00:00:00 2001
From: mlugg <mlugg@mlugg.co.uk>
Date: Sat, 10 Jun 2023 00:56:29 +0100
Subject: [PATCH] Sema: emit error on @intToPtr with slice dest type

Resolves: #15967
---
 src/Sema.zig                                        | 10 ++++++++++
 test/cases/compile_errors/inttoptr_non_ptr_type.zig |  6 ++++++
 2 files changed, 16 insertions(+)

diff --git a/src/Sema.zig b/src/Sema.zig
index 44daa02780..aed4dc7248 100644
--- a/src/Sema.zig
+++ b/src/Sema.zig
@@ -19794,6 +19794,16 @@ fn zirIntToPtr(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Ai
     const target = sema.mod.getTarget();
     const ptr_align = try ptr_ty.ptrAlignmentAdvanced(target, sema);
 
+    if (ptr_ty.isSlice()) {
+        const msg = msg: {
+            const msg = try sema.errMsg(block, type_src, "integer cannot be converted to slice type '{}'", .{ptr_ty.fmt(sema.mod)});
+            errdefer msg.destroy(sema.gpa);
+            try sema.errNote(block, type_src, msg, "slice length cannot be inferred from address", .{});
+            break :msg msg;
+        };
+        return sema.failWithOwnedErrorMsg(msg);
+    }
+
     if (try sema.resolveDefinedValue(block, operand_src, operand_coerced)) |val| {
         const addr = val.toUnsignedInt(target);
         if (!ptr_ty.isAllowzeroPtr() and addr == 0)
diff --git a/test/cases/compile_errors/inttoptr_non_ptr_type.zig b/test/cases/compile_errors/inttoptr_non_ptr_type.zig
index 6a8af0ab95..fa308f677d 100644
--- a/test/cases/compile_errors/inttoptr_non_ptr_type.zig
+++ b/test/cases/compile_errors/inttoptr_non_ptr_type.zig
@@ -2,8 +2,14 @@ pub export fn entry() void {
     _ = @intToPtr(i32, 10);
 }
 
+pub export fn entry2() void {
+    _ = @intToPtr([]u8, 20);
+}
+
 // error
 // backend=stage2
 // target=native
 //
 // :2:19: error: expected pointer type, found 'i32'
+// :6:19: error: integer cannot be converted to slice type '[]u8'
+// :6:19: note: slice length cannot be inferred from address