diff --git a/src/Sema.zig b/src/Sema.zig
index c5d8d638b2..ae00a9852f 100644
--- a/src/Sema.zig
+++ b/src/Sema.zig
@@ -28499,7 +28499,13 @@ fn resolveInferredErrorSet(
     // in this case, it may be a generic function which would cause an assertion failure
     // if we called `ensureFuncBodyAnalyzed` on it here.
     const ies_func_owner_decl = sema.mod.declPtr(ies.func.owner_decl);
-    if (ies_func_owner_decl.ty.fnInfo().return_type.errorUnionSet().castTag(.error_set_inferred).?.data == ies) {
+    const ies_func_info = ies_func_owner_decl.ty.fnInfo();
+    // if ies declared by a inline function with generic return type, the return_type should be generic_poison,
+    // because inline function does not create a new declaration, and the ies has been filled with analyzeCall,
+    // so here we can simply skip this case.
+    if (ies_func_info.return_type.tag() == .generic_poison) {
+        assert(ies_func_info.cc == .Inline);
+    } else if (ies_func_info.return_type.errorUnionSet().castTag(.error_set_inferred).?.data == ies) {
         // In this case we are dealing with the actual InferredErrorSet object that
         // corresponds to the function, not one created to track an inline/comptime call.
         try sema.ensureFuncBodyAnalyzed(ies.func);
diff --git a/test/behavior.zig b/test/behavior.zig
index 648757d56f..019d9bbac7 100644
--- a/test/behavior.zig
+++ b/test/behavior.zig
@@ -87,6 +87,7 @@ test {
     _ = @import("behavior/bugs/12430.zig");
     _ = @import("behavior/bugs/12486.zig");
     _ = @import("behavior/bugs/12551.zig");
+    _ = @import("behavior/bugs/12644.zig");
     _ = @import("behavior/bugs/12680.zig");
     _ = @import("behavior/bugs/12776.zig");
     _ = @import("behavior/bugs/12786.zig");
diff --git a/test/behavior/bugs/12644.zig b/test/behavior/bugs/12644.zig
new file mode 100644
index 0000000000..36874c12cb
--- /dev/null
+++ b/test/behavior/bugs/12644.zig
@@ -0,0 +1,15 @@
+const std = @import("std");
+
+inline fn foo(comptime T: type) !T {
+    return error.AnError;
+}
+
+fn main0() !void {
+    _ = try foo(u8);
+}
+
+test "issue12644" {
+    main0() catch |e| {
+        try std.testing.expect(e == error.AnError);
+    };
+}