diff --git a/pkg/smith/pubspec.yaml b/pkg/smith/pubspec.yaml
index 92b76a5c714..444539ed0ec 100644
--- a/pkg/smith/pubspec.yaml
+++ b/pkg/smith/pubspec.yaml
@@ -4,7 +4,7 @@ description: Shared code for working with the Dart SDK's tests and test runner.
 publish_to: none
 
 environment:
-  sdk: ^3.5.0
+  sdk: '^3.12.0-0'
 
 resolution: workspace
 
diff --git a/pkg/status_file/lib/expectation.dart b/pkg/status_file/lib/expectation.dart
index 8898b7911d7..d4b4ce23bec 100644
--- a/pkg/status_file/lib/expectation.dart
+++ b/pkg/status_file/lib/expectation.dart
@@ -205,9 +205,8 @@ class Expectation {
   /// Whether this expectation is a test outcome. If not, it's a "meta marker".
   final bool isOutcome;
 
-  Expectation._(this._name, {Expectation? group, bool isMeta = false})
-      : _group = group,
-        isOutcome = !isMeta;
+  Expectation._(this._name, {this._group, bool isMeta = false})
+      : isOutcome = !isMeta;
 
   bool canBeOutcomeOf(Expectation expectation) {
     Expectation? outcome = this;
diff --git a/pkg/status_file/pubspec.yaml b/pkg/status_file/pubspec.yaml
index f3193fd88c8..a271d70fdbe 100644
--- a/pkg/status_file/pubspec.yaml
+++ b/pkg/status_file/pubspec.yaml
@@ -3,7 +3,7 @@ name: status_file
 publish_to: none
 
 environment:
-  sdk: ^3.5.0
+  sdk: '^3.12.0-0'
 
 resolution: workspace
 
diff --git a/pkg/test_runner/lib/src/command.dart b/pkg/test_runner/lib/src/command.dart
index a81fb51c83f..6607328efe3 100644
--- a/pkg/test_runner/lib/src/command.dart
+++ b/pkg/test_runner/lib/src/command.dart
@@ -170,11 +170,10 @@ class CompilationCommand extends ProcessCommand {
       String executable,
       List<String> arguments,
       Map<String, String> environmentOverrides,
-      {required bool alwaysCompile,
+      {required this._alwaysCompile,
       String? workingDirectory,
       int index = 0})
-      : _alwaysCompile = alwaysCompile,
-        super(displayName, executable, arguments, environmentOverrides,
+      : super(displayName, executable, arguments, environmentOverrides,
             workingDirectory, index);
 
   @override
diff --git a/pkg/test_runner/lib/src/compiler_configuration.dart b/pkg/test_runner/lib/src/compiler_configuration.dart
index bb79cc36e44..77c37e5df84 100644
--- a/pkg/test_runner/lib/src/compiler_configuration.dart
+++ b/pkg/test_runner/lib/src/compiler_configuration.dart
@@ -1116,7 +1116,7 @@ class PrecompilerCompilerConfiguration extends CompilerConfiguration
     }
 
     var args = [
-      if (target != null) ...target,
+      ...?target,
       ...ldFlags,
       shared,
       '-o',
diff --git a/pkg/test_runner/lib/src/configuration.dart b/pkg/test_runner/lib/src/configuration.dart
index dea6e14ab3d..9d606015c6c 100644
--- a/pkg/test_runner/lib/src/configuration.dart
+++ b/pkg/test_runner/lib/src/configuration.dart
@@ -33,7 +33,7 @@ class TestConfiguration {
       this.build = false,
       this.testList = const [],
       this.deflakeInfoMap = const {},
-      int repeat = 1,
+      this._repeat = 1,
       this.batch = false,
       this.copyCoreDumps = false,
       this.rr = false,
@@ -76,8 +76,7 @@ class TestConfiguration {
       : packages = packages ??
             Repository.uri
                 .resolve('.dart_tool/package_config.json')
-                .toFilePath(),
-        _repeat = repeat;
+                .toFilePath();
 
   final Map<String, RegExp?> selectors;
   final Progress progress;
diff --git a/pkg/test_runner/lib/src/path.dart b/pkg/test_runner/lib/src/path.dart
index de23bc5d86a..ac3a5c4b487 100644
--- a/pkg/test_runner/lib/src/path.dart
+++ b/pkg/test_runner/lib/src/path.dart
@@ -240,7 +240,7 @@ class Path {
 
     var segmentsToJoin = [
       if (isAbs) '',
-      if (drive != null) drive,
+      ?drive,
       if (newSegs.isEmpty) ...[
         if (isAbs) '' else '.'
       ] else ...[
diff --git a/pkg/test_runner/pubspec.yaml b/pkg/test_runner/pubspec.yaml
index 4402b547ff9..cc8e545a00a 100644
--- a/pkg/test_runner/pubspec.yaml
+++ b/pkg/test_runner/pubspec.yaml
@@ -7,7 +7,7 @@ name: test_runner
 publish_to: none
 
 environment:
-  sdk: ^3.5.0
+  sdk: '^3.12.0-0'
 
 resolution: workspace