diff --git a/tests/simple/testdata/type_deduction.textproto b/tests/simple/testdata/type_deduction.textproto
index 1a0e261..f6cf94c 100644
--- a/tests/simple/testdata/type_deduction.textproto
+++ b/tests/simple/testdata/type_deduction.textproto
@@ -951,3 +951,150 @@ section {
     }
   }
 }
+
+section {
+  name: "type_decay"
+  description: "Tests for type decay / least-upper-bound generalization of type values."
+  test {
+    name: "type_list_decay"
+    expr: "[int, bool, double]"
+    typed_result {
+      result {
+        list_value {
+          values {
+            type_value: "int"
+          }
+          values {
+            type_value: "bool"
+          }
+          values {
+            type_value: "double"
+          }
+        }
+      }
+      deduced_type {
+        list_type {
+          elem_type {
+            type {
+              dyn {}
+            }
+          }
+        }
+      }
+    }
+  }
+  test {
+    name: "type_ternary_decay"
+    expr: "true ? type(1) : type(1u)"
+    typed_result {
+      result {
+        type_value: "int"
+      }
+      deduced_type {
+        type {
+          dyn {}
+        }
+      }
+    }
+  }
+  test {
+    name: "type_free_param_list_decay"
+    description: "Type decay for list literal containing a free type parameter in a type value and a concrete type."
+    expr: "[type([]), int]"
+    typed_result {
+      result {
+        list_value {
+          values {
+            type_value: "list"
+          }
+          values {
+            type_value: "int"
+          }
+        }
+      }
+      deduced_type {
+        list_type {
+          elem_type {
+            dyn {}
+          }
+        }
+      }
+    }
+  }
+  test {
+    name: "type_nested_list_decay"
+    description: "Type decay for nested list literal with differing type values."
+    expr: "[[type(1)], [type(1u)]]"
+    typed_result {
+      result {
+        list_value {
+          values {
+            list_value {
+              values {
+                type_value: "int"
+              }
+            }
+          }
+          values {
+            list_value {
+              values {
+                type_value: "uint"
+              }
+            }
+          }
+        }
+      }
+      deduced_type {
+        list_type {
+          elem_type {
+            list_type {
+              elem_type {
+                type {
+                  dyn {}
+                }
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+  test {
+    name: "type_free_param_list_concat"
+    description: "Type deduction for concatenated lists containing free type parameters in type values."
+    expr: "([] + [[type(1)]]) + [[type([])]]"
+    typed_result {
+      result {
+        list_value {
+          values {
+            list_value {
+              values {
+                type_value: "int"
+              }
+            }
+          }
+          values {
+            list_value {
+              values {
+                type_value: "list"
+              }
+            }
+          }
+        }
+      }
+      deduced_type {
+        list_type {
+          elem_type {
+            list_type {
+              elem_type {
+                type {
+                  dyn {}
+                }
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+}