Model cadence's Future.Get as an error-return non-nil-arg hook

hook/error_return.go

@@ -86,4 +86,14 @@ var _errorReturnNonnilArgs = map[trustedSig]struct {
 		enclosingRegex: regexp.MustCompile(`^encoding/(json|xml)$`),
 		nameRegex:      regexp.MustCompile(`^Unmarshal$`),
 	}: {action: pointeeOfArg, argIndex: 1},
+
+	// `(cadence).Future.Get(ctx, &v)` blocks until the future is ready and, on success (a nil error
+	// return), populates the value pointed to by `&v`, so a nil error return implies `v != nil`. The
+	// `Future` interface lives in `go.uber.org/cadence/internal` and is re-exported (via a type alias)
+	// as `go.uber.org/cadence/workflow.Future`, so the method's declaring package is the internal one.
+	{
+		kind:           _method,
+		enclosingRegex: regexp.MustCompile(`^(stubs/)?go\.uber\.org/cadence/internal\.Future$`),
+		nameRegex:      regexp.MustCompile(`^Get$`),
+	}: {action: pointeeOfArg, argIndex: 1},
 }

testdata/src/go.uber.org/trustedfunc/inference/cadence.go

@@ -0,0 +1,38 @@
+package inference
+
+import "stubs/go.uber.org/cadence/workflow"
+
+// testCadenceFutureGet exercises the `ErrorReturnNonnilArg` hook for cadence's `Future.Get`:
+// `f.Get(ctx, &v)` populates `v`, so the pointee is treated as non-nil once the error return is
+// checked to be nil.
+func testCadenceFutureGet(ctx workflow.Context, f workflow.Future) {
+	// `err != nil` early return: pointee is non-nil on the fallthrough (error-is-nil) path.
+	var v1 *int
+	if err := f.Get(ctx, &v1); err != nil {
+		return
+	}
+	print(*v1) // safe
+
+	// `err == nil` positive check: pointee is non-nil inside the block.
+	var v2 *int
+	err := f.Get(ctx, &v2)
+	if err == nil {
+		print(*v2) // safe
+	}
+
+	// Error return not checked at all: no guarantee.
+	var v3 *int
+	f.Get(ctx, &v3)
+	print(*v3) //want "unassigned variable `v3` dereferenced"
+
+	// Error return discarded into the blank identifier: no guarantee.
+	var v4 *int
+	_ = f.Get(ctx, &v4)
+	print(*v4) //want "unassigned variable `v4` dereferenced"
+
+	// Dereference on the error path (`err != nil`): pointee is not guarded here.
+	var v5 *int
+	if err := f.Get(ctx, &v5); err != nil {
+		print(*v5) //want "unassigned variable `v5` dereferenced"
+	}
+}

testdata/src/stubs/go.uber.org/cadence/internal/internal.go

@@ -0,0 +1,30 @@
+//  Copyright (c) 2026 Uber Technologies, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package internal is a minimal stub of `go.uber.org/cadence/internal`, which is where the `Future`
+// interface (re-exported as `go.uber.org/cadence/workflow.Future`) is actually declared.
+package internal
+
+// Context is a minimal stub of cadence's workflow context.
+type Context interface {
+	Value(key interface{}) interface{}
+}
+
+// Future is a minimal stub of cadence's `Future` interface. Its `Get` method blocks until the
+// future is ready and, on success (a nil error return), populates the value pointed to by
+// `valuePtr` (passed by address as `&v`).
+type Future interface {
+	Get(ctx Context, valuePtr interface{}) error
+	IsReady() bool
+}

testdata/src/stubs/go.uber.org/cadence/workflow/workflow.go

@@ -0,0 +1,26 @@
+//  Copyright (c) 2026 Uber Technologies, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package workflow is a minimal stub of `go.uber.org/cadence/workflow`. Like the real package, it
+// re-exports the `Future` and `Context` types from the internal package via type aliases, so a call
+// to `f.Get(ctx, &v)` resolves to the method declared in `go.uber.org/cadence/internal`.
+package workflow
+
+import "stubs/go.uber.org/cadence/internal"
+
+// Context aliases internal.Context, mirroring the real cadence package.
+type Context = internal.Context
+
+// Future aliases internal.Future, mirroring the real cadence package.
+type Future = internal.Future