Add second test case for asserts predicate and convert to testdata files

Co-authored-by: RyanCavanaugh <6685088+RyanCavanaugh@users.noreply.github.com>

Author: Copilot

internal/checker/checker_test.go

@@ -80,71 +80,6 @@ func TestCheckSrcCompiler(t *testing.T) {
 	p.CheckSourceFiles(t.Context(), nil)
 }
 
-func TestTypePredicateParameterMismatch(t *testing.T) {
-	t.Parallel()
-
-	// This test verifies that the checker doesn't panic when a type predicate
-	// references a parameter name that doesn't match any actual function parameter.
-	// The issue was that getTypePredicateArgument would try to access the arguments
-	// array with a negative index (-1) when the parameter name wasn't found.
-	content := `type TypeA = { kind: 'a' };
-type TypeB = { kind: 'b' };
-type UnionType = TypeA | TypeB;
-
-function isTypeA(
-  _value: UnionType
-): value is TypeA {  // "value" doesn't match parameter "_value"
-  return true;
-}
-
-function test(input: UnionType): void {
-  if (isTypeA(input)) {
-    console.log(input.kind);
-  }
-}`
-	fs := vfstest.FromMap(map[string]string{
-		"/test.ts": content,
-		"/tsconfig.json": `
-				{
-					"compilerOptions": {
-						"target": "es2015",
-						"module": "commonjs",
-						"strict": true
-					},
-					"files": ["test.ts"]
-				}
-			`,
-	}, false /*useCaseSensitiveFileNames*/)
-	fs = bundled.WrapFS(fs)
-
-	cd := "/"
-	host := compiler.NewCompilerHost(cd, fs, bundled.LibPath(), nil, nil)
-
-	parsed, errors := tsoptions.GetParsedCommandLineOfConfigFile("/tsconfig.json", &core.CompilerOptions{}, host, nil)
-	assert.Equal(t, len(errors), 0, "Expected no errors in parsed command line")
-
-	p := compiler.NewProgram(compiler.ProgramOptions{
-		Config: parsed,
-		Host:   host,
-	})
-
-	// This should not panic - it should report a diagnostic error instead
-	diags := p.GetSemanticDiagnostics(t.Context(), nil)
-
-	// We expect at least one diagnostic error (TS1225: Cannot find parameter 'value')
-	assert.Assert(t, len(diags) > 0, "Expected at least one diagnostic error")
-
-	// Verify the expected error code is present
-	foundExpectedError := false
-	for _, diag := range diags {
-		if diag.Code() == 1225 { // TS1225: Cannot find parameter
-			foundExpectedError = true
-			break
-		}
-	}
-	assert.Assert(t, foundExpectedError, "Expected to find error TS1225 (Cannot find parameter)")
-}
-
 func BenchmarkNewChecker(b *testing.B) {
 	repo.SkipIfNoTypeScriptSubmodule(b)
 	fs := osvfs.FS()

testdata/tests/cases/compiler/assertsPredicateParameterMismatch.ts

@@ -0,0 +1,19 @@
+// @strict: true
+// @noemit: true
+
+// This test verifies that the checker doesn't panic when an assertion predicate
+// references a parameter name that doesn't match any actual function parameter.
+// This specifically tests the code path in isReachableFlowNodeWorker.
+
+function assertCondition(
+  _condition: boolean
+): asserts condition {  // "condition" doesn't match parameter "_condition"
+  if (!_condition) {
+    throw new Error('Condition failed');
+  }
+}
+
+function test(): void {
+  assertCondition(false);
+  console.log("unreachable");
+}

testdata/tests/cases/compiler/typePredicateParameterMismatch.ts

@@ -0,0 +1,21 @@
+// @strict: true
+// @noemit: true
+
+// This test verifies that the checker doesn't panic when a type predicate
+// references a parameter name that doesn't match any actual function parameter.
+
+type TypeA = { kind: 'a' };
+type TypeB = { kind: 'b' };
+type UnionType = TypeA | TypeB;
+
+function isTypeA(
+  _value: UnionType
+): value is TypeA {  // "value" doesn't match parameter "_value"
+  return true;
+}
+
+function test(input: UnionType): void {
+  if (isTypeA(input)) {
+    console.log(input.kind);
+  }
+}