diff --git a/explorer/BUILD b/explorer/BUILD
index 918de0eee9a6..e60654c17cf7 100644
--- a/explorer/BUILD
+++ b/explorer/BUILD
@@ -46,7 +46,10 @@ file_test(
     # Bazel limits sharding to 50. We have lots of tests, so this should
     # maximize parallelism.
     shard_count = 50,
-    tests = glob(["testdata/**/*.carbon"]),
+    tests = glob([
+        "testdata/**/*.carbon",
+        "trace_testdata/**/*.carbon",
+    ]),
     deps = [
         "//explorer/parse_and_execute",
         "//testing/file_test:file_test_base",
diff --git a/explorer/autoupdate_trace_testdata.py b/explorer/autoupdate_trace_testdata.py
new file mode 100755
index 000000000000..4952637e9a5f
--- /dev/null
+++ b/explorer/autoupdate_trace_testdata.py
@@ -0,0 +1,35 @@
+#!/usr/bin/env python3
+
+"""Updates the CHECK: lines in tests with an AUTOUPDATE line."""
+
+__copyright__ = """
+Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+Exceptions. See /LICENSE for license information.
+SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+"""
+
+import subprocess
+import sys
+from pathlib import Path
+
+
+def main() -> None:
+    # Subprocess to the main script in order to avoid Python import behaviors.
+    this_py = Path(__file__).resolve()
+    autoupdate_py = this_py.parent.parent.joinpath(
+        "testing", "scripts", "autoupdate_testdata_base.py"
+    )
+
+    args = [
+        str(autoupdate_py),
+        # Flags to configure for explorer testing.
+        "--tool=explorer",
+        "--testdata=explorer/trace_testdata",
+        "--autoupdate_arg=--trace_file=-",
+        "--autoupdate_arg=-trace_all",
+    ] + sys.argv[1:]
+    exit(subprocess.call(args))
+
+
+if __name__ == "__main__":
+    main()
diff --git a/explorer/file_test.cpp b/explorer/file_test.cpp
index db17e94c395f..baa890afae59 100644
--- a/explorer/file_test.cpp
+++ b/explorer/file_test.cpp
@@ -16,9 +16,14 @@ class ParseAndExecuteTestFile : public FileTestBase {
       : FileTestBase(path), trace_(trace) {}
 
   auto SetUp() -> void override {
+    std::string path_str = path().string();
+    llvm::StringRef path_ref = path_str;
+
+    if (path_ref.find("trace_testdata") != llvm::StringRef::npos) {
+      is_trace_test = true;
+    }
+
     if (trace_) {
-      std::string path_str = path().string();
-      llvm::StringRef path_ref = path_str;
       if (path_ref.find("/limits/") != llvm::StringRef::npos) {
         GTEST_SKIP()
             << "`limits` tests check for various limit conditions (such as an "
@@ -30,6 +35,10 @@ class ParseAndExecuteTestFile : public FileTestBase {
                      "testdata/linked_list/typed_linked_list.carbon")) {
         GTEST_SKIP() << "Expensive test to trace";
       }
+    } else {
+      if (is_trace_test) {
+        GTEST_SKIP() << "`trace` tests only check for trace output.";
+      }
     }
   }
 
@@ -46,7 +55,7 @@ class ParseAndExecuteTestFile : public FileTestBase {
     TraceStream trace_stream;
     TestRawOstream trace_stream_ostream;
     if (trace_) {
-      trace_stream.set_stream(&trace_stream_ostream);
+      trace_stream.set_stream(is_trace_test ? &stdout : &trace_stream_ostream);
       trace_stream.set_allowed_phases({ProgramPhase::All});
     }
 
@@ -68,7 +77,9 @@ class ParseAndExecuteTestFile : public FileTestBase {
       stderr << result.error() << "\n";
     }
 
-    if (trace_) {
+    // Skip trace test check as they use stdout stream instead of
+    // trace_stream_ostream
+    if (trace_ && !is_trace_test) {
       EXPECT_FALSE(trace_stream_ostream.TakeStr().empty())
           << "Tracing should always do something";
     }
@@ -78,6 +89,7 @@ class ParseAndExecuteTestFile : public FileTestBase {
 
  private:
   bool trace_;
+  bool is_trace_test = false;
 };
 
 }  // namespace
diff --git a/explorer/trace_testdata/full_trace.carbon b/explorer/trace_testdata/full_trace.carbon
new file mode 100644
index 000000000000..6ed986171726
--- /dev/null
+++ b/explorer/trace_testdata/full_trace.carbon
@@ -0,0 +1,1308 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+// AUTOUPDATE
+// CHECK:STDOUT: ********** source program **********
+// CHECK:STDOUT: interface TestInterface {
+// CHECK:STDOUT: }
+// CHECK:STDOUT: fn Main ()-> i32 {
+// CHECK:STDOUT: {
+// CHECK:STDOUT: return 0;
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: }
+// CHECK:STDOUT: ********** resolving names **********
+// CHECK:STDOUT: ********** resolving control flow **********
+// CHECK:STDOUT: ********** type checking **********
+// CHECK:STDOUT: Omitting prelude type checking traces...
+// CHECK:STDOUT: Finished prelude, resuming traces...
+// CHECK:STDOUT: ** declaring interface TestInterface
+// CHECK:STDOUT: ** finished declaring interface TestInterface
+// CHECK:STDOUT: checking InterfaceDeclaration
+// CHECK:STDOUT: ** checking interface TestInterface
+// CHECK:STDOUT: impl declarations:{{ }}
+// CHECK:STDOUT: impl declarations: bool as interface EqWith(U = bool), i32 as interface EqWith(U = i32), String as interface EqWith(U = String), i32 as interface CompareWith(U = i32), String as interface CompareWith(U = String), i32 as interface LessWith(U = i32), String as interface LessWith(U = String), i32 as interface LessEqWith(U = i32), String as interface LessEqWith(U = String), i32 as interface GreaterWith(U = i32), String as interface GreaterWith(U = String), i32 as interface GreaterEqWith(U = i32), String as interface GreaterEqWith(U = String), i32 as interface Negate, i32 as interface AddWith(U = i32), i32 as interface SubWith(U = i32), i32 as interface MulWith(U = i32), i32 as interface DivWith(U = i32), i32 as interface ModWith(U = i32), i32 as interface BitComplement, i32 as interface BitAndWith(U = i32), i32 as interface BitOrWith(U = i32), i32 as interface BitXorWith(U = i32), i32 as interface LeftShiftWith(U = i32), i32 as interface RightShiftWith(U = i32), i32 as interface Inc, i32 as interface Dec, U as interface __EqualConverter [0], (T1,) as interface As(T = (U1,)) [0, 0, 0; 1, 1, 0, 0, 0], (T1, T2) as interface As(T = (U1, U2)) [0, 0, 0; 0, 0, 1; 1, 1, 0, 0, 0; 1, 1, 0, 0, 1], (T1, U1) as interface EqWith(U = (T2, U2)) [0, 0, 0; 0, 0, 1; 1, 1, 0, 0, 0; 1, 1, 0, 0, 1], (T1, T2, T3) as interface As(T = (U1, U2, U3)) [0, 0, 0; 0, 0, 1; 0, 0, 2; 1, 1, 0, 0, 0; 1, 1, 0, 0, 1; 1, 1, 0, 0, 2], T as interface ImplicitAs(T = U) [0; 1, 1, 0], T as interface As(T = U) [0; 1, 1, 0], T as interface ImplicitAs(T = U) [0; 1, 1, 0], T as interface As(T = U) [0; 1, 1, 0], T as interface AssignWith(U = U) [0; 1, 1, 0], T as interface AddAssignWith(U = U) [0; 1, 1, 0], T as interface SubAssignWith(U = U) [0; 1, 1, 0], T as interface MulAssignWith(U = U) [0; 1, 1, 0], T as interface DivAssignWith(U = U) [0; 1, 1, 0], T as interface ModAssignWith(U = U) [0; 1, 1, 0], T as interface BitAndAssignWith(U = U) [0; 1, 1, 0], T as interface BitOrAssignWith(U = U) [0; 1, 1, 0], T as interface BitXorAssignWith(U = U) [0; 1, 1, 0], T as interface LeftShiftAssignWith(U = U) [0; 1, 1, 0], T as interface RightShiftAssignWith(U = U) [0; 1, 1, 0]
+// CHECK:STDOUT: ** finished checking interface TestInterface
+// CHECK:STDOUT: ** declaring function Main
+// CHECK:STDOUT: checking TuplePattern ()
+// CHECK:STDOUT: checking IntTypeLiteral i32
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+
+
+package ExplorerTest api;
+
+interface TestInterface {}
+
+// CHECK:STDOUT: --- step exp i32 .0. (full_trace.carbon:[[@LINE+1184]]) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: ** finished declaring function Main of type fn () -> i32
+// CHECK:STDOUT: checking FunctionDeclaration
+// CHECK:STDOUT: ** checking function Main
+// CHECK:STDOUT: impl declarations:{{ }}
+// CHECK:STDOUT: impl declarations: bool as interface EqWith(U = bool), i32 as interface EqWith(U = i32), String as interface EqWith(U = String), i32 as interface CompareWith(U = i32), String as interface CompareWith(U = String), i32 as interface LessWith(U = i32), String as interface LessWith(U = String), i32 as interface LessEqWith(U = i32), String as interface LessEqWith(U = String), i32 as interface GreaterWith(U = i32), String as interface GreaterWith(U = String), i32 as interface GreaterEqWith(U = i32), String as interface GreaterEqWith(U = String), i32 as interface Negate, i32 as interface AddWith(U = i32), i32 as interface SubWith(U = i32), i32 as interface MulWith(U = i32), i32 as interface DivWith(U = i32), i32 as interface ModWith(U = i32), i32 as interface BitComplement, i32 as interface BitAndWith(U = i32), i32 as interface BitOrWith(U = i32), i32 as interface BitXorWith(U = i32), i32 as interface LeftShiftWith(U = i32), i32 as interface RightShiftWith(U = i32), i32 as interface Inc, i32 as interface Dec, U as interface __EqualConverter [0], (T1,) as interface As(T = (U1,)) [0, 0, 0; 1, 1, 0, 0, 0], (T1, T2) as interface As(T = (U1, U2)) [0, 0, 0; 0, 0, 1; 1, 1, 0, 0, 0; 1, 1, 0, 0, 1], (T1, U1) as interface EqWith(U = (T2, U2)) [0, 0, 0; 0, 0, 1; 1, 1, 0, 0, 0; 1, 1, 0, 0, 1], (T1, T2, T3) as interface As(T = (U1, U2, U3)) [0, 0, 0; 0, 0, 1; 0, 0, 2; 1, 1, 0, 0, 0; 1, 1, 0, 0, 1; 1, 1, 0, 0, 2], T as interface ImplicitAs(T = U) [0; 1, 1, 0], T as interface As(T = U) [0; 1, 1, 0], T as interface ImplicitAs(T = U) [0; 1, 1, 0], T as interface As(T = U) [0; 1, 1, 0], T as interface AssignWith(U = U) [0; 1, 1, 0], T as interface AddAssignWith(U = U) [0; 1, 1, 0], T as interface SubAssignWith(U = U) [0; 1, 1, 0], T as interface MulAssignWith(U = U) [0; 1, 1, 0], T as interface DivAssignWith(U = U) [0; 1, 1, 0], T as interface ModAssignWith(U = U) [0; 1, 1, 0], T as interface BitAndAssignWith(U = U) [0; 1, 1, 0], T as interface BitOrAssignWith(U = U) [0; 1, 1, 0], T as interface BitXorAssignWith(U = U) [0; 1, 1, 0], T as interface LeftShiftAssignWith(U = U) [0; 1, 1, 0], T as interface RightShiftAssignWith(U = U) [0; 1, 1, 0]
+// CHECK:STDOUT: checking Block {
+// CHECK:STDOUT: return 0;
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: checking ReturnExpression return 0;
+// CHECK:STDOUT: checking IntLiteral 0
+// CHECK:STDOUT: ** finished checking function Main
+// CHECK:STDOUT: checking CallExpression Main()
+// CHECK:STDOUT: checking IdentifierExpression Main
+// CHECK:STDOUT: checking TupleLiteral ()
+// CHECK:STDOUT: checking call to function of type fn () -> i32
+// CHECK:STDOUT: with arguments of type: ()
+// CHECK:STDOUT: performing argument deduction for bindings:{{ }}
+// CHECK:STDOUT: deduction succeeded with results: {}
+// CHECK:STDOUT: ********** resolving unformed variables **********
+// CHECK:STDOUT: ********** printing declarations **********
+// CHECK:STDOUT: interface TestInterface {
+// CHECK:STDOUT: }
+// CHECK:STDOUT: fn Main ()-> i32 {
+// CHECK:STDOUT: {
+// CHECK:STDOUT: return 0;
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: }
+// CHECK:STDOUT: ********** starting execution **********
+// CHECK:STDOUT: ********** initializing globals **********
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface As .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface ImplicitAs .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface __EqualConverter .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl fn __EqualConvert .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl forall [U:! type] U as __EqualConverter where .T = U .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl match_first .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl forall [U1:! type, T1:! As(U1)] (T1) as As((U1)) .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl forall [U1:! type, U2:! type, T1:! As(U1), T2:! As(U2)] (T1, T2) as As((U1, U2)) .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl forall [U1:! type, U2:! type, U3:! type, T1:! As(U1), T2:! As(U2), T3:! As(U3)] (T1, T2, T3) as As((U1, U2, U3)) .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface EqWith .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl constraint Eq .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl forall [T2:! type, U2:! type, T1:! EqWith(T2), U1:! EqWith(U2)] (T1, U1) as EqWith((T2, U2)) .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl bool as EqWith(Self) .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl i32 as EqWith(Self) .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl String as EqWith(Self) .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl choice Ordering .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface CompareWith .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl constraint Ordered .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl i32 as CompareWith(Self) .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl String as CompareWith(Self) .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface LessWith .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface LessEqWith .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface GreaterWith .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface GreaterEqWith .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl i32 as LessWith(Self) .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl String as LessWith(Self) .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl i32 as LessEqWith(Self) .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl String as LessEqWith(Self) .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl i32 as GreaterWith(Self) .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl String as GreaterWith(Self) .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl i32 as GreaterEqWith(Self) .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl String as GreaterEqWith(Self) .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface Negate .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface AddWith .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl constraint Add .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface SubWith .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl constraint Sub .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface MulWith .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl constraint Mul .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface DivWith .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl constraint Div .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface ModWith .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl constraint Mod .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl i32 as Negate where .Result = i32 .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl i32 as AddWith(i32) where .Result = i32 .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl i32 as SubWith(i32) where .Result = i32 .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl i32 as MulWith(i32) where .Result = i32 .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl i32 as DivWith(i32) where .Result = i32 .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl i32 as ModWith(i32) where .Result = i32 .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface BitComplement .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface BitAndWith .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl constraint BitAnd .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface BitOrWith .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl constraint BitOr .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface BitXorWith .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl constraint BitXor .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface LeftShiftWith .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl constraint LeftShift .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface RightShiftWith .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl constraint RightShift .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl i32 as BitComplement where .Result = i32 .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl i32 as BitAndWith(i32) where .Result = i32 .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl i32 as BitOrWith(i32) where .Result = i32 .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl i32 as BitXorWith(i32) where .Result = i32 .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl i32 as LeftShiftWith(i32) where .Result = i32 .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl i32 as RightShiftWith(i32) where .Result = i32 .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface AssignWith .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl constraint Assign .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface AddAssignWith .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl constraint AddAssign .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface SubAssignWith .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl constraint SubAssign .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface MulAssignWith .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl constraint MulAssign .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface DivAssignWith .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl constraint DivAssign .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface ModAssignWith .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl constraint ModAssign .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface BitAndAssignWith .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl constraint BitAssignAnd .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface BitOrAssignWith .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl constraint BitAssignOr .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface BitXorAssignWith .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl constraint BitAssignXor .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface LeftShiftAssignWith .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl constraint LeftShiftAssign .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface RightShiftAssignWith .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl constraint RightShiftAssign .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl forall [T:! type, U:! ImplicitAs(T)] T as AssignWith(U) .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl forall [U:! type, T:! AddWith(U) where .Self impls AssignWith(.Self.Result)] T as AddAssignWith(U) .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl forall [U:! type, T:! SubWith(U) where .Self impls AssignWith(.Self.Result)] T as SubAssignWith(U) .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl forall [U:! type, T:! MulWith(U) where .Self impls AssignWith(.Self.Result)] T as MulAssignWith(U) .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl forall [U:! type, T:! DivWith(U) where .Self impls AssignWith(.Self.Result)] T as DivAssignWith(U) .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl forall [U:! type, T:! ModWith(U) where .Self impls AssignWith(.Self.Result)] T as ModAssignWith(U) .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl forall [U:! type, T:! BitAndWith(U) where .Self impls AssignWith(.Self.Result)] T as BitAndAssignWith(U) .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl forall [U:! type, T:! BitOrWith(U) where .Self impls AssignWith(.Self.Result)] T as BitOrAssignWith(U) .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl forall [U:! type, T:! BitXorWith(U) where .Self impls AssignWith(.Self.Result)] T as BitXorAssignWith(U) .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl forall [U:! type, T:! LeftShiftWith(U) where .Self impls AssignWith(.Self.Result)] T as LeftShiftAssignWith(U) .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl forall [U:! type, T:! RightShiftWith(U) where .Self impls AssignWith(.Self.Result)] T as RightShiftAssignWith(U) .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface Inc .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface Dec .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl i32 as Inc .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl impl i32 as Dec .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl fn Assert .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl fn Rand .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl choice OptionalElement .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl class Optional .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl class Heap .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl var heap: Heap .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: {}.(interface ImplicitAs(T = class Heap).Convert)() .0. ## var heap: Heap = {}.(interface ImplicitAs(T = class Heap).Convert)();
+// CHECK:STDOUT:  .1.
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step exp {}.(interface ImplicitAs(T = class Heap).Convert)() .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: {}.(interface ImplicitAs(T = class Heap).Convert) .0. ## {}.(interface ImplicitAs(T = class Heap).Convert)() .1. ## var heap: Heap = {}.(interface ImplicitAs(T = class Heap).Convert)();
+// CHECK:STDOUT:  .1.
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step exp {}.(interface ImplicitAs(T = class Heap).Convert) .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: {} .0. ## {}.(interface ImplicitAs(T = class Heap).Convert) .1. ## {}.(interface ImplicitAs(T = class Heap).Convert)() .1. ## var heap: Heap = {}.(interface ImplicitAs(T = class Heap).Convert)();
+// CHECK:STDOUT:  .1.
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step exp {} .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: {}.(interface ImplicitAs(T = class Heap).Convert) .1. {{[[][[]}}{}]] ## {}.(interface ImplicitAs(T = class Heap).Convert)() .1. ## var heap: Heap = {}.(interface ImplicitAs(T = class Heap).Convert)();
+// CHECK:STDOUT:  .1.
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step exp {}.(interface ImplicitAs(T = class Heap).Convert) .1. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: witness for impl T as ImplicitAs(U) .0. ## {}.(interface ImplicitAs(T = class Heap).Convert) .2. {{[[][[]}}{}]] ## {}.(interface ImplicitAs(T = class Heap).Convert)() .1. ## var heap: Heap = {}.(interface ImplicitAs(T = class Heap).Convert)();
+// CHECK:STDOUT:  .1.
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step witness witness for impl T as ImplicitAs(U) .0. --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: {}.(interface ImplicitAs(T = class Heap).Convert) .2. {{[[][[]}}{}, witness for impl T as ImplicitAs(U)]] ## {}.(interface ImplicitAs(T = class Heap).Convert)() .1. ## var heap: Heap = {}.(interface ImplicitAs(T = class Heap).Convert)();
+// CHECK:STDOUT:  .1.
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step exp {}.(interface ImplicitAs(T = class Heap).Convert) .2. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: interface As(T = class Heap) .0. ## {}.(interface ImplicitAs(T = class Heap).Convert) .3. {{[[][[]}}{}, witness for impl T as ImplicitAs(U)]] ## {}.(interface ImplicitAs(T = class Heap).Convert)() .1. ## var heap: Heap = {}.(interface ImplicitAs(T = class Heap).Convert)();
+// CHECK:STDOUT:  .1.
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: {}.(interface ImplicitAs(T = class Heap).Convert) .3. {{[[][[]}}{}, witness for impl T as ImplicitAs(U), interface As(T = class Heap)]] ## {}.(interface ImplicitAs(T = class Heap).Convert)() .1. ## var heap: Heap = {}.(interface ImplicitAs(T = class Heap).Convert)();
+// CHECK:STDOUT:  .1.
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step exp {}.(interface ImplicitAs(T = class Heap).Convert) .3. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: {}.(interface ImplicitAs(T = class Heap).Convert) .4. {{[[][[]}}{}, witness for impl T as ImplicitAs(U), interface As(T = class Heap)]] ## {}.(interface ImplicitAs(T = class Heap).Convert)() .1. ## var heap: Heap = {}.(interface ImplicitAs(T = class Heap).Convert)();
+// CHECK:STDOUT:  .1.
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step exp {}.(interface ImplicitAs(T = class Heap).Convert) .4. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: {}.(interface ImplicitAs(T = class Heap).Convert)() .1. {{[[][[]}}bound_method<Convert>]] ## var heap: Heap = {}.(interface ImplicitAs(T = class Heap).Convert)();
+// CHECK:STDOUT:  .1.
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step exp {}.(interface ImplicitAs(T = class Heap).Convert)() .1. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: () .0. ## {}.(interface ImplicitAs(T = class Heap).Convert)() .2. {{[[][[]}}bound_method<Convert>]] ## var heap: Heap = {}.(interface ImplicitAs(T = class Heap).Convert)();
+// CHECK:STDOUT:  .1.
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step exp () .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: {}.(interface ImplicitAs(T = class Heap).Convert)() .2. {{[[][[]}}bound_method<Convert>, ()]] ## var heap: Heap = {}.(interface ImplicitAs(T = class Heap).Convert)();
+// CHECK:STDOUT:  .1.
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step exp {}.(interface ImplicitAs(T = class Heap).Convert)() .2. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: calling function: bound_method<Convert>
+// CHECK:STDOUT: match pattern ()
+// CHECK:STDOUT: from value expression with value ()
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: {return __intrinsic_implicit_as_convert(self, U);} .0. ## .0. {self: Self: {}} ## {}.(interface ImplicitAs(T = class Heap).Convert)() .3. {{[[][[]}}bound_method<Convert>, ()]] {} ## var heap: Heap = {}.(interface ImplicitAs(T = class Heap).Convert)();
+// CHECK:STDOUT:  .1.
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step stmt {return __intrinsic_implicit_as_convert(self, U);} .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: return __intrinsic_implicit_as_convert(self, U); .0. ## {return __intrinsic_implicit_as_convert(self, U);} .1. {} ## .0. {self: Self: {}} ## {}.(interface ImplicitAs(T = class Heap).Convert)() .3. {{[[][[]}}bound_method<Convert>, ()]] {} ## var heap: Heap = {}.(interface ImplicitAs(T = class Heap).Convert)();
+// CHECK:STDOUT:  .1.
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step stmt return __intrinsic_implicit_as_convert(self, U); .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: __intrinsic_implicit_as_convert(self, U) .0. ## return __intrinsic_implicit_as_convert(self, U); .1. ## {return __intrinsic_implicit_as_convert(self, U);} .1. {} ## .0. {self: Self: {}} ## {}.(interface ImplicitAs(T = class Heap).Convert)() .3. {{[[][[]}}bound_method<Convert>, ()]] {} ## var heap: Heap = {}.(interface ImplicitAs(T = class Heap).Convert)();
+// CHECK:STDOUT:  .1.
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step exp __intrinsic_implicit_as_convert(self, U) .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: self .0. ## return __intrinsic_implicit_as_convert(self, U); .1. ## {return __intrinsic_implicit_as_convert(self, U);} .1. {} ## .0. {self: Self: {}} ## {}.(interface ImplicitAs(T = class Heap).Convert)() .3. {{[[][[]}}bound_method<Convert>, ()]] {} ## var heap: Heap = {}.(interface ImplicitAs(T = class Heap).Convert)();
+// CHECK:STDOUT:  .1.
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step exp self .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: self .0. ## self .1. ## return __intrinsic_implicit_as_convert(self, U); .1. ## {return __intrinsic_implicit_as_convert(self, U);} .1. {} ## .0. {self: Self: {}} ## {}.(interface ImplicitAs(T = class Heap).Convert)() .3. {{[[][[]}}bound_method<Convert>, ()]] {} ## var heap: Heap = {}.(interface ImplicitAs(T = class Heap).Convert)();
+// CHECK:STDOUT:  .1.
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step exp self .0. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: self .1. {{[[][[]}}{}]] ## return __intrinsic_implicit_as_convert(self, U); .1. ## {return __intrinsic_implicit_as_convert(self, U);} .1. {} ## .0. {self: Self: {}} ## {}.(interface ImplicitAs(T = class Heap).Convert)() .3. {{[[][[]}}bound_method<Convert>, ()]] {} ## var heap: Heap = {}.(interface ImplicitAs(T = class Heap).Convert)();
+// CHECK:STDOUT:  .1.
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step exp self .1. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: class Heap .0. ## self .2. {{[[][[]}}{}]] ## return __intrinsic_implicit_as_convert(self, U); .1. ## {return __intrinsic_implicit_as_convert(self, U);} .1. {} ## .0. {self: Self: {}} ## {}.(interface ImplicitAs(T = class Heap).Convert)() .3. {{[[][[]}}bound_method<Convert>, ()]] {} ## var heap: Heap = {}.(interface ImplicitAs(T = class Heap).Convert)();
+// CHECK:STDOUT:  .1.
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: self .2. {{[[][[]}}{}, class Heap]] ## return __intrinsic_implicit_as_convert(self, U); .1. ## {return __intrinsic_implicit_as_convert(self, U);} .1. {} ## .0. {self: Self: {}} ## {}.(interface ImplicitAs(T = class Heap).Convert)() .3. {{[[][[]}}bound_method<Convert>, ()]] {} ## var heap: Heap = {}.(interface ImplicitAs(T = class Heap).Convert)();
+// CHECK:STDOUT:  .1.
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step exp self .2. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: return __intrinsic_implicit_as_convert(self, U); .1. {{[[][[]}}Heap{}]] ## {return __intrinsic_implicit_as_convert(self, U);} .1. {} ## .0. {self: Self: {}} ## {}.(interface ImplicitAs(T = class Heap).Convert)() .3. {{[[][[]}}bound_method<Convert>, ()]] {} ## var heap: Heap = {}.(interface ImplicitAs(T = class Heap).Convert)();
+// CHECK:STDOUT:  .1.
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step stmt return __intrinsic_implicit_as_convert(self, U); .1. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: clean up.0. {} ## clean up.0. {self: Self: {}} ## {}.(interface ImplicitAs(T = class Heap).Convert)() .3. {{[[][[]}}bound_method<Convert>, (), Heap{}]] {} ## var heap: Heap = {}.(interface ImplicitAs(T = class Heap).Convert)();
+// CHECK:STDOUT:  .1.
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: clean up.0. {self: Self: {}} ## {}.(interface ImplicitAs(T = class Heap).Convert)() .3. {{[[][[]}}bound_method<Convert>, (), Heap{}]] {} ## var heap: Heap = {}.(interface ImplicitAs(T = class Heap).Convert)();
+// CHECK:STDOUT:  .1.
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: {}.(interface ImplicitAs(T = class Heap).Convert)() .3. {{[[][[]}}bound_method<Convert>, (), Heap{}]] {} ## var heap: Heap = {}.(interface ImplicitAs(T = class Heap).Convert)();
+// CHECK:STDOUT:  .1.
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step exp {}.(interface ImplicitAs(T = class Heap).Convert)() .3. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: clean up.0. {} ## var heap: Heap = {}.(interface ImplicitAs(T = class Heap).Convert)();
+// CHECK:STDOUT:  .1. {{[[][[]}}Heap{}]]
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: var heap: Heap = {}.(interface ImplicitAs(T = class Heap).Convert)();
+// CHECK:STDOUT:  .1. {{[[][[]}}Heap{}]]
+// CHECK:STDOUT: memory:{{ }}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl var heap: Heap .1. ({{.*}}/explorer/data/prelude.carbon:{{.*}}) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory: 0: Heap{}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory: 0: Heap{}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step decl interface TestInterface .0. (full_trace.carbon:[[@LINE-1177]]) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory: 0: Heap{}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory: 0: Heap{}
+// CHECK:STDOUT: }
+fn Main() -> i32 {
+  return 0;
+// CHECK:STDOUT: --- step decl fn Main .0. (full_trace.carbon:[[@LINE+82]]) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory: 0: Heap{}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: ********** calling main function **********
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory: 0: Heap{}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step exp Main() .0. (<Main()>:0) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: Main .0. ## Main() .1.
+// CHECK:STDOUT: memory: 0: Heap{}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step exp Main .0. (<Main()>:0) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: Main() .1. {{[[][[]}}fun<Main>]]
+// CHECK:STDOUT: memory: 0: Heap{}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step exp Main() .1. (<Main()>:0) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: () .0. ## Main() .2. {{[[][[]}}fun<Main>]]
+// CHECK:STDOUT: memory: 0: Heap{}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step exp () .0. (<Main()>:0) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: Main() .2. {{[[][[]}}fun<Main>, ()]]
+// CHECK:STDOUT: memory: 0: Heap{}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step exp Main() .2. (<Main()>:0) --->
+// CHECK:STDOUT: calling function: fun<Main>
+// CHECK:STDOUT: match pattern ()
+// CHECK:STDOUT: from value expression with value ()
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: {return 0;} .0. ## .0. {} ## Main() .3. {{[[][[]}}fun<Main>, ()]] {}
+// CHECK:STDOUT: memory: 0: Heap{}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step stmt {return 0;} .0. (full_trace.carbon:[[@LINE+44]]) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: return 0; .0. ## {return 0;} .1. {} ## .0. {} ## Main() .3. {{[[][[]}}fun<Main>, ()]] {}
+// CHECK:STDOUT: memory: 0: Heap{}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step stmt return 0; .0. (full_trace.carbon:[[@LINE-44]]) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: 0 .0. ## return 0; .1. ## {return 0;} .1. {} ## .0. {} ## Main() .3. {{[[][[]}}fun<Main>, ()]] {}
+// CHECK:STDOUT: memory: 0: Heap{}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step exp 0 .0. (full_trace.carbon:[[@LINE-49]]) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: return 0; .1. {{[[][[]}}0]] ## {return 0;} .1. {} ## .0. {} ## Main() .3. {{[[][[]}}fun<Main>, ()]] {}
+// CHECK:STDOUT: memory: 0: Heap{}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step stmt return 0; .1. (full_trace.carbon:[[@LINE-54]]) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: clean up.0. {} ## clean up.0. {} ## Main() .3. {{[[][[]}}fun<Main>, (), 0]] {}
+// CHECK:STDOUT: memory: 0: Heap{}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: clean up.0. {} ## Main() .3. {{[[][[]}}fun<Main>, (), 0]] {}
+// CHECK:STDOUT: memory: 0: Heap{}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: Main() .3. {{[[][[]}}fun<Main>, (), 0]] {}
+// CHECK:STDOUT: memory: 0: Heap{}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: --- step exp Main() .3. (<Main()>:0) --->
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack: clean up.0. {}
+// CHECK:STDOUT: memory: 0: Heap{}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: {
+// CHECK:STDOUT: stack:{{ }}
+// CHECK:STDOUT: memory: 0: Heap{}
+// CHECK:STDOUT: }
+// CHECK:STDOUT: interpreter result: 0
+// CHECK:STDOUT: ********** printing timing **********
+// CHECK:STDOUT: Time elapsed in ExecProgram: {{[0-9]+}}ms
+// CHECK:STDOUT: Time elapsed in AnalyzeProgram: {{[0-9]+}}ms
+// CHECK:STDOUT: Time elapsed in AddPrelude: {{[0-9]+}}ms
+// CHECK:STDOUT: Time elapsed in Parse: {{[0-9]+}}ms
+// CHECK:STDOUT: result: 0
+}
diff --git a/testing/scripts/autoupdate_testdata_base.py b/testing/scripts/autoupdate_testdata_base.py
index 7df02f5c3e9b..c7016c4fe482 100755
--- a/testing/scripts/autoupdate_testdata_base.py
+++ b/testing/scripts/autoupdate_testdata_base.py
@@ -198,9 +198,13 @@ class CheckLine(Line):
         super().__init__()
         self.filename = Path(test).name
         self.indent = ""
-        self.out_line = out_line.rstrip()
+        self.out_line = out_line
         self.line_number_delta_prefix = line_number_delta_prefix
         self.line_number_pattern = line_number_pattern
+        self.time_elapsed_pattern = re.compile(
+            r"Time elapsed in (\S+): (\d+)ms"
+        )
+        self.trailing_whitespace_pattern = re.compile(r"(\s+$)")
 
         # If any match is specific to this file, use the first matched line for
         # the location of the CHECK comment.
@@ -216,26 +220,36 @@ class CheckLine(Line):
         assert self.out_line
         result = self.out_line
         while True:
-            match = self.line_number_pattern.search(result)
-            if not match:
-                break
-            if self._matches_filename(match):
-                line_number = int(match.group("line")) - 1
-                delta = line_number_remap[line_number] - output_line_number
-                # We use `:+d` here to produce `LINE-n` or `LINE+n` as
-                # appropriate.
-                result = self.line_number_pattern.sub(
-                    rf"\g<prefix>{self.line_number_delta_prefix}"
-                    rf"[[@LINE{delta:+d}]]\g<suffix>",
-                    result,
-                    count=1,
+            line_match = self.line_number_pattern.search(result)
+            time_match = self.time_elapsed_pattern.search(result)
+            trailing_match = self.trailing_whitespace_pattern.search(result)
+            if line_match:
+                if self._matches_filename(line_match):
+                    line_number = int(line_match.group("line")) - 1
+                    delta = line_number_remap[line_number] - output_line_number
+                    # We use `:+d` here to produce `LINE-n` or `LINE+n` as
+                    # appropriate.
+                    result = self.line_number_pattern.sub(
+                        rf"\g<prefix>{self.line_number_delta_prefix}"
+                        rf"[[@LINE{delta:+d}]]\g<suffix>",
+                        result,
+                        count=1,
+                    )
+                else:
+                    result = self.line_number_pattern.sub(
+                        r"\g<prefix>{{.*}}\g<suffix>",
+                        result,
+                        count=1,
+                    )
+            elif time_match:
+                result = self.time_elapsed_pattern.sub(
+                    r"Time elapsed in \1: {{[0-9]+}}ms", result, count=1
                 )
+            elif trailing_match:
+                result = self.trailing_whitespace_pattern.sub(r"{{\1}}", result)
             else:
-                result = self.line_number_pattern.sub(
-                    r"\g<prefix>{{.*}}\g<suffix>",
-                    result,
-                    count=1,
-                )
+                break
+
         return f"{self.indent}// CHECK:{result}\n"
 
     def _matches_filename(self, match: Match) -> bool: