Move diagnostic kind name to the end of the diagnostic. (#4437)

Also surround it in square brackets rather than parentheses. This matches the format used by Clang and GCC, and means diagnostics will still match the `file:line:col: error: ` pattern used by some IDE tools. Before: ```console fail_builtins.carbon:11:11: error(AliasRequiresNameRef): alias initializer must be a name reference ``` After: ```console fail_builtins.carbon:11:11: error: alias initializer must be a name reference [AliasRequiresNameRef] ``` Also tighten up test regex to only match on `STDERR` lines that list a file name.
2026-10-05 12:51:04 +01:00 · 2024-10-23 16:56:23 +00:00
parent f206072216
commit 2e63da1a40
528 changed files with 1929 additions and 1928 deletions
@@ -9,30 +9,30 @@
 // TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/function/builtin/fail_redefined.carbon

 fn A(n: i32, m: i32) -> i32 = "int.sadd";
-// CHECK:STDERR: fail_redefined.carbon:[[@LINE+7]]:1: error(RedeclRedef): redefinition of `fn A`
+// CHECK:STDERR: fail_redefined.carbon:[[@LINE+7]]:1: error: redefinition of `fn A` [RedeclRedef]
 // CHECK:STDERR: fn A(n: i32, m: i32) -> i32 { return n; }
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-// CHECK:STDERR: fail_redefined.carbon:[[@LINE-4]]:1: note(RedeclPrevDef): previously defined here
+// CHECK:STDERR: fail_redefined.carbon:[[@LINE-4]]:1: note: previously defined here [RedeclPrevDef]
 // CHECK:STDERR: fn A(n: i32, m: i32) -> i32 = "int.sadd";
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 // CHECK:STDERR:
 fn A(n: i32, m: i32) -> i32 { return n; }

 fn B(n: i32, m: i32) -> i32 { return n; }
-// CHECK:STDERR: fail_redefined.carbon:[[@LINE+7]]:1: error(RedeclRedef): redefinition of `fn B`
+// CHECK:STDERR: fail_redefined.carbon:[[@LINE+7]]:1: error: redefinition of `fn B` [RedeclRedef]
 // CHECK:STDERR: fn B(n: i32, m: i32) -> i32 = "int.sadd";
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-// CHECK:STDERR: fail_redefined.carbon:[[@LINE-4]]:1: note(RedeclPrevDef): previously defined here
+// CHECK:STDERR: fail_redefined.carbon:[[@LINE-4]]:1: note: previously defined here [RedeclPrevDef]
 // CHECK:STDERR: fn B(n: i32, m: i32) -> i32 { return n; }
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 // CHECK:STDERR:
 fn B(n: i32, m: i32) -> i32 = "int.sadd";

 fn C(n: i32, m: i32) -> i32 = "int.sadd";
-// CHECK:STDERR: fail_redefined.carbon:[[@LINE+6]]:1: error(RedeclRedef): redefinition of `fn C`
+// CHECK:STDERR: fail_redefined.carbon:[[@LINE+6]]:1: error: redefinition of `fn C` [RedeclRedef]
 // CHECK:STDERR: fn C(n: i32, m: i32) -> i32 = "int.sadd";
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-// CHECK:STDERR: fail_redefined.carbon:[[@LINE-4]]:1: note(RedeclPrevDef): previously defined here
+// CHECK:STDERR: fail_redefined.carbon:[[@LINE-4]]:1: note: previously defined here [RedeclPrevDef]
 // CHECK:STDERR: fn C(n: i32, m: i32) -> i32 = "int.sadd";
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 fn C(n: i32, m: i32) -> i32 = "int.sadd";
@@ -8,7 +8,7 @@
 // TIP: To dump output, run:
 // TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/function/builtin/fail_unknown.carbon

-// CHECK:STDERR: fail_unknown.carbon:[[@LINE+3]]:23: error(UnknownBuiltinFunctionName): unknown builtin function name "unknown.builtin.name"
+// CHECK:STDERR: fail_unknown.carbon:[[@LINE+3]]:23: error: unknown builtin function name "unknown.builtin.name" [UnknownBuiltinFunctionName]
 // CHECK:STDERR: fn UnknownBuiltin() = "unknown.builtin.name";
 // CHECK:STDERR:                       ^~~~~~~~~~~~~~~~~~~~~~
 fn UnknownBuiltin() = "unknown.builtin.name";
@@ -9,7 +9,7 @@
 // TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/function/call/fail_not_callable.carbon

 fn Run() {
-  // CHECK:STDERR: fail_not_callable.carbon:[[@LINE+3]]:16: error(CallToNonCallable): value of type `String` is not callable
+  // CHECK:STDERR: fail_not_callable.carbon:[[@LINE+3]]:16: error: value of type `String` is not callable [CallToNonCallable]
  // CHECK:STDERR:   var x: i32 = "hello"();
  // CHECK:STDERR:                ^~~~~~~~
  var x: i32 = "hello"();
@@ -13,52 +13,52 @@ fn Run1(a: i32) {}
 fn Run2(a: i32, b: i32) {}

 fn Main() {
-  // CHECK:STDERR: fail_param_count.carbon:[[@LINE+7]]:3: error(CallArgCountMismatch): 1 argument passed to function expecting 0 arguments
+  // CHECK:STDERR: fail_param_count.carbon:[[@LINE+7]]:3: error: 1 argument passed to function expecting 0 arguments [CallArgCountMismatch]
  // CHECK:STDERR:   Run0(1);
  // CHECK:STDERR:   ^~~~~
-  // CHECK:STDERR: fail_param_count.carbon:[[@LINE-8]]:1: note(InCallToEntity): calling function declared here
+  // CHECK:STDERR: fail_param_count.carbon:[[@LINE-8]]:1: note: calling function declared here [InCallToEntity]
  // CHECK:STDERR: fn Run0() {}
  // CHECK:STDERR: ^~~~~~~~~~~
  // CHECK:STDERR:
  Run0(1);
-  // CHECK:STDERR: fail_param_count.carbon:[[@LINE+7]]:3: error(CallArgCountMismatch): 2 arguments passed to function expecting 0 arguments
+  // CHECK:STDERR: fail_param_count.carbon:[[@LINE+7]]:3: error: 2 arguments passed to function expecting 0 arguments [CallArgCountMismatch]
  // CHECK:STDERR:   Run0(0, 1);
  // CHECK:STDERR:   ^~~~~
-  // CHECK:STDERR: fail_param_count.carbon:[[@LINE-16]]:1: note(InCallToEntity): calling function declared here
+  // CHECK:STDERR: fail_param_count.carbon:[[@LINE-16]]:1: note: calling function declared here [InCallToEntity]
  // CHECK:STDERR: fn Run0() {}
  // CHECK:STDERR: ^~~~~~~~~~~
  // CHECK:STDERR:
  Run0(0, 1);

-  // CHECK:STDERR: fail_param_count.carbon:[[@LINE+7]]:3: error(CallArgCountMismatch): 0 arguments passed to function expecting 1 argument
+  // CHECK:STDERR: fail_param_count.carbon:[[@LINE+7]]:3: error: 0 arguments passed to function expecting 1 argument [CallArgCountMismatch]
  // CHECK:STDERR:   Run1();
  // CHECK:STDERR:   ^~~~~
-  // CHECK:STDERR: fail_param_count.carbon:[[@LINE-24]]:1: note(InCallToEntity): calling function declared here
+  // CHECK:STDERR: fail_param_count.carbon:[[@LINE-24]]:1: note: calling function declared here [InCallToEntity]
  // CHECK:STDERR: fn Run1(a: i32) {}
  // CHECK:STDERR: ^~~~~~~~~~~~~~~~~
  // CHECK:STDERR:
  Run1();
-  // CHECK:STDERR: fail_param_count.carbon:[[@LINE+7]]:3: error(CallArgCountMismatch): 2 arguments passed to function expecting 1 argument
+  // CHECK:STDERR: fail_param_count.carbon:[[@LINE+7]]:3: error: 2 arguments passed to function expecting 1 argument [CallArgCountMismatch]
  // CHECK:STDERR:   Run1(0, 1);
  // CHECK:STDERR:   ^~~~~
-  // CHECK:STDERR: fail_param_count.carbon:[[@LINE-32]]:1: note(InCallToEntity): calling function declared here
+  // CHECK:STDERR: fail_param_count.carbon:[[@LINE-32]]:1: note: calling function declared here [InCallToEntity]
  // CHECK:STDERR: fn Run1(a: i32) {}
  // CHECK:STDERR: ^~~~~~~~~~~~~~~~~
  // CHECK:STDERR:
  Run1(0, 1);

-  // CHECK:STDERR: fail_param_count.carbon:[[@LINE+7]]:3: error(CallArgCountMismatch): 0 arguments passed to function expecting 2 arguments
+  // CHECK:STDERR: fail_param_count.carbon:[[@LINE+7]]:3: error: 0 arguments passed to function expecting 2 arguments [CallArgCountMismatch]
  // CHECK:STDERR:   Run2();
  // CHECK:STDERR:   ^~~~~
-  // CHECK:STDERR: fail_param_count.carbon:[[@LINE-40]]:1: note(InCallToEntity): calling function declared here
+  // CHECK:STDERR: fail_param_count.carbon:[[@LINE-40]]:1: note: calling function declared here [InCallToEntity]
  // CHECK:STDERR: fn Run2(a: i32, b: i32) {}
  // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~
  // CHECK:STDERR:
  Run2();
-  // CHECK:STDERR: fail_param_count.carbon:[[@LINE+6]]:3: error(CallArgCountMismatch): 1 argument passed to function expecting 2 arguments
+  // CHECK:STDERR: fail_param_count.carbon:[[@LINE+6]]:3: error: 1 argument passed to function expecting 2 arguments [CallArgCountMismatch]
  // CHECK:STDERR:   Run2(0);
  // CHECK:STDERR:   ^~~~~
-  // CHECK:STDERR: fail_param_count.carbon:[[@LINE-48]]:1: note(InCallToEntity): calling function declared here
+  // CHECK:STDERR: fail_param_count.carbon:[[@LINE-48]]:1: note: calling function declared here [InCallToEntity]
  // CHECK:STDERR: fn Run2(a: i32, b: i32) {}
  // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~
  Run2(0);
@@ -11,13 +11,13 @@
 fn G(a: i32) {}

 fn F() {
-  // CHECK:STDERR: fail_param_type.carbon:[[@LINE+9]]:5: error(ImplicitAsConversionFailure): cannot implicitly convert from `f64` to `i32`
+  // CHECK:STDERR: fail_param_type.carbon:[[@LINE+9]]:5: error: cannot implicitly convert from `f64` to `i32` [ImplicitAsConversionFailure]
  // CHECK:STDERR:   G(1.0);
  // CHECK:STDERR:     ^~~
-  // CHECK:STDERR: fail_param_type.carbon:[[@LINE+6]]:5: note(MissingImplInMemberAccessNote): type `f64` does not implement interface `ImplicitAs`
+  // CHECK:STDERR: fail_param_type.carbon:[[@LINE+6]]:5: note: type `f64` does not implement interface `ImplicitAs` [MissingImplInMemberAccessNote]
  // CHECK:STDERR:   G(1.0);
  // CHECK:STDERR:     ^~~
-  // CHECK:STDERR: fail_param_type.carbon:[[@LINE-9]]:6: note(InCallToFunctionParam): initializing function parameter
+  // CHECK:STDERR: fail_param_type.carbon:[[@LINE-9]]:6: note: initializing function parameter [InCallToFunctionParam]
  // CHECK:STDERR: fn G(a: i32) {}
  // CHECK:STDERR:      ^~~~~~
  G(1.0);
@@ -11,10 +11,10 @@
 fn Foo() -> f64 { return 1.0; }

 fn Run() {
-  // CHECK:STDERR: fail_return_type_mismatch.carbon:[[@LINE+6]]:3: error(ImplicitAsConversionFailure): cannot implicitly convert from `f64` to `i32`
+  // CHECK:STDERR: fail_return_type_mismatch.carbon:[[@LINE+6]]:3: error: cannot implicitly convert from `f64` to `i32` [ImplicitAsConversionFailure]
  // CHECK:STDERR:   var x: i32 = Foo();
  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~~~
-  // CHECK:STDERR: fail_return_type_mismatch.carbon:[[@LINE+3]]:3: note(MissingImplInMemberAccessNote): type `f64` does not implement interface `ImplicitAs`
+  // CHECK:STDERR: fail_return_type_mismatch.carbon:[[@LINE+3]]:3: note: type `f64` does not implement interface `ImplicitAs` [MissingImplInMemberAccessNote]
  // CHECK:STDERR:   var x: i32 = Foo();
  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~~~
  var x: i32 = Foo();
@@ -8,7 +8,7 @@
 // TIP: To dump output, run:
 // TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/function/call/no_prelude/fail_explicit_self_param.carbon

-// CHECK:STDERR: fail_explicit_self_param.carbon:[[@LINE+3]]:6: error(SelfOutsideImplicitParamList): `self` can only be declared in an implicit parameter list
+// CHECK:STDERR: fail_explicit_self_param.carbon:[[@LINE+3]]:6: error: `self` can only be declared in an implicit parameter list [SelfOutsideImplicitParamList]
 // CHECK:STDERR: fn F(self: ());
 // CHECK:STDERR:      ^~~~~~~~
 fn F(self: ());
@@ -8,7 +8,7 @@
 // TIP: To dump output, run:
 // TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/function/call/no_prelude/fail_runtime_implicit_param.carbon

-// CHECK:STDERR: fail_runtime_implicit_param.carbon:[[@LINE+3]]:6: error(ImplictParamMustBeConstant): implicit parameters of functions must be constant or `self`
+// CHECK:STDERR: fail_runtime_implicit_param.carbon:[[@LINE+3]]:6: error: implicit parameters of functions must be constant or `self` [ImplictParamMustBeConstant]
 // CHECK:STDERR: fn F[s: ()]();
 // CHECK:STDERR:      ^~~~~
 fn F[s: ()]();
@@ -8,7 +8,7 @@
 // TIP: To dump output, run:
 // TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/function/declaration/fail_param_in_type.carbon

-// CHECK:STDERR: fail_param_in_type.carbon:[[@LINE+3]]:23: error(InvalidArrayExpr): array bound is not a constant
+// CHECK:STDERR: fail_param_in_type.carbon:[[@LINE+3]]:23: error: array bound is not a constant [InvalidArrayExpr]
 // CHECK:STDERR: fn F(n: i32, a: [i32; n]*);
 // CHECK:STDERR:                       ^
 fn F(n: i32, a: [i32; n]*);
@@ -8,10 +8,10 @@
 // TIP: To dump output, run:
 // TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/function/declaration/fail_param_redecl.carbon

-// CHECK:STDERR: fail_param_redecl.carbon:[[@LINE+6]]:14: error(NameDeclDuplicate): duplicate name being declared in the same scope
+// CHECK:STDERR: fail_param_redecl.carbon:[[@LINE+6]]:14: error: duplicate name being declared in the same scope [NameDeclDuplicate]
 // CHECK:STDERR: fn F(n: i32, n: i32);
 // CHECK:STDERR:              ^
-// CHECK:STDERR: fail_param_redecl.carbon:[[@LINE+3]]:6: note(NameDeclPrevious): name is previously declared here
+// CHECK:STDERR: fail_param_redecl.carbon:[[@LINE+3]]:6: note: name is previously declared here [NameDeclPrevious]
 // CHECK:STDERR: fn F(n: i32, n: i32);
 // CHECK:STDERR:      ^
 fn F(n: i32, n: i32);
@@ -58,47 +58,47 @@ library "[[@TEST_NAME]]";

 import library "api";

-// CHECK:STDERR: fail_redecl_api.carbon:[[@LINE+8]]:1: error(RedeclExternMismatch): redeclarations of `fn A` must match use of `extern`
+// CHECK:STDERR: fail_redecl_api.carbon:[[@LINE+8]]:1: error: redeclarations of `fn A` must match use of `extern` [RedeclExternMismatch]
 // CHECK:STDERR: extern fn A();
 // CHECK:STDERR: ^~~~~~~~~~~~~~
-// CHECK:STDERR: fail_redecl_api.carbon:[[@LINE-5]]:1(InImport): in import
-// CHECK:STDERR: api.carbon:4:1: note(RedeclPrevDecl): previously declared here
+// CHECK:STDERR: fail_redecl_api.carbon:[[@LINE-5]]:1: in import [InImport]
+// CHECK:STDERR: api.carbon:4:1: note: previously declared here [RedeclPrevDecl]
 // CHECK:STDERR: fn A();
 // CHECK:STDERR: ^~~~~~~
 // CHECK:STDERR:
 extern fn A();
-// CHECK:STDERR: fail_redecl_api.carbon:[[@LINE+8]]:1: error(RedeclExternMismatch): redeclarations of `fn B` must match use of `extern`
+// CHECK:STDERR: fail_redecl_api.carbon:[[@LINE+8]]:1: error: redeclarations of `fn B` must match use of `extern` [RedeclExternMismatch]
 // CHECK:STDERR: extern fn B(b: i32) -> i32;
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~
-// CHECK:STDERR: fail_redecl_api.carbon:[[@LINE-14]]:1(InImport): in import
-// CHECK:STDERR: api.carbon:5:1: note(RedeclPrevDecl): previously declared here
+// CHECK:STDERR: fail_redecl_api.carbon:[[@LINE-14]]:1: in import [InImport]
+// CHECK:STDERR: api.carbon:5:1: note: previously declared here [RedeclPrevDecl]
 // CHECK:STDERR: fn B(b: i32) -> i32;
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~
 // CHECK:STDERR:
 extern fn B(b: i32) -> i32;
-// CHECK:STDERR: fail_redecl_api.carbon:[[@LINE+8]]:1: error(RedeclExternMismatch): redeclarations of `fn C` must match use of `extern`
+// CHECK:STDERR: fail_redecl_api.carbon:[[@LINE+8]]:1: error: redeclarations of `fn C` must match use of `extern` [RedeclExternMismatch]
 // CHECK:STDERR: extern fn C(c: (i32,)) -> {.c: i32};
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-// CHECK:STDERR: fail_redecl_api.carbon:[[@LINE-23]]:1(InImport): in import
-// CHECK:STDERR: api.carbon:6:1: note(RedeclPrevDecl): previously declared here
+// CHECK:STDERR: fail_redecl_api.carbon:[[@LINE-23]]:1: in import [InImport]
+// CHECK:STDERR: api.carbon:6:1: note: previously declared here [RedeclPrevDecl]
 // CHECK:STDERR: fn C(c: (i32,)) -> {.c: i32};
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 // CHECK:STDERR:
 extern fn C(c: (i32,)) -> {.c: i32};
-// CHECK:STDERR: fail_redecl_api.carbon:[[@LINE+8]]:1: error(RedeclRedundant): redeclaration of `fn D` is redundant
+// CHECK:STDERR: fail_redecl_api.carbon:[[@LINE+8]]:1: error: redeclaration of `fn D` is redundant [RedeclRedundant]
 // CHECK:STDERR: extern fn D();
 // CHECK:STDERR: ^~~~~~~~~~~~~~
-// CHECK:STDERR: fail_redecl_api.carbon:[[@LINE-32]]:1(InImport): in import
-// CHECK:STDERR: api.carbon:7:1: note(RedeclPrevDecl): previously declared here
+// CHECK:STDERR: fail_redecl_api.carbon:[[@LINE-32]]:1: in import [InImport]
+// CHECK:STDERR: api.carbon:7:1: note: previously declared here [RedeclPrevDecl]
 // CHECK:STDERR: extern fn D();
 // CHECK:STDERR: ^~~~~~~~~~~~~~
 // CHECK:STDERR:
 extern fn D();
-// CHECK:STDERR: fail_redecl_api.carbon:[[@LINE+8]]:1: error(RedeclExternMismatch): redeclarations of `fn E` must match use of `extern`
+// CHECK:STDERR: fail_redecl_api.carbon:[[@LINE+8]]:1: error: redeclarations of `fn E` must match use of `extern` [RedeclExternMismatch]
 // CHECK:STDERR: extern fn NS.E();
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~
-// CHECK:STDERR: fail_redecl_api.carbon:[[@LINE-41]]:1(InImport): in import
-// CHECK:STDERR: api.carbon:10:1: note(RedeclPrevDecl): previously declared here
+// CHECK:STDERR: fail_redecl_api.carbon:[[@LINE-41]]:1: in import [InImport]
+// CHECK:STDERR: api.carbon:10:1: note: previously declared here [RedeclPrevDecl]
 // CHECK:STDERR: fn NS.E();
 // CHECK:STDERR: ^~~~~~~~~~
 // CHECK:STDERR:
@@ -132,48 +132,48 @@ var e: () = NS.E();

 library "[[@TEST_NAME]]";

-// CHECK:STDERR: fail_merge.carbon:[[@LINE+45]]:1(InImport): in import
-// CHECK:STDERR: extern_api.carbon:4:1: error(NameDeclDuplicate): duplicate name being declared in the same scope
+// CHECK:STDERR: fail_merge.carbon:[[@LINE+45]]:1: in import [InImport]
+// CHECK:STDERR: extern_api.carbon:4:1: error: duplicate name being declared in the same scope [NameDeclDuplicate]
 // CHECK:STDERR: extern library "redecl_extern_api" fn A();
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-// CHECK:STDERR: fail_merge.carbon:[[@LINE+41]]:1(InImport): in import
-// CHECK:STDERR: api.carbon:4:1: note(NameDeclPrevious): name is previously declared here
+// CHECK:STDERR: fail_merge.carbon:[[@LINE+41]]:1: in import [InImport]
+// CHECK:STDERR: api.carbon:4:1: note: name is previously declared here [NameDeclPrevious]
 // CHECK:STDERR: fn A();
 // CHECK:STDERR: ^~~~~~~
 // CHECK:STDERR:
-// CHECK:STDERR: fail_merge.carbon:[[@LINE+36]]:1(InImport): in import
-// CHECK:STDERR: extern_api.carbon:5:1: error(NameDeclDuplicate): duplicate name being declared in the same scope
+// CHECK:STDERR: fail_merge.carbon:[[@LINE+36]]:1: in import [InImport]
+// CHECK:STDERR: extern_api.carbon:5:1: error: duplicate name being declared in the same scope [NameDeclDuplicate]
 // CHECK:STDERR: extern library "redecl_extern_api" fn B(b: i32) -> i32;
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-// CHECK:STDERR: fail_merge.carbon:[[@LINE+32]]:1(InImport): in import
-// CHECK:STDERR: api.carbon:5:1: note(NameDeclPrevious): name is previously declared here
+// CHECK:STDERR: fail_merge.carbon:[[@LINE+32]]:1: in import [InImport]
+// CHECK:STDERR: api.carbon:5:1: note: name is previously declared here [NameDeclPrevious]
 // CHECK:STDERR: fn B(b: i32) -> i32;
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~
 // CHECK:STDERR:
-// CHECK:STDERR: fail_merge.carbon:[[@LINE+27]]:1(InImport): in import
-// CHECK:STDERR: extern_api.carbon:6:1: error(NameDeclDuplicate): duplicate name being declared in the same scope
+// CHECK:STDERR: fail_merge.carbon:[[@LINE+27]]:1: in import [InImport]
+// CHECK:STDERR: extern_api.carbon:6:1: error: duplicate name being declared in the same scope [NameDeclDuplicate]
 // CHECK:STDERR: extern library "redecl_extern_api" fn C(c: (i32,)) -> {.c: i32};
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-// CHECK:STDERR: fail_merge.carbon:[[@LINE+23]]:1(InImport): in import
-// CHECK:STDERR: api.carbon:6:1: note(NameDeclPrevious): name is previously declared here
+// CHECK:STDERR: fail_merge.carbon:[[@LINE+23]]:1: in import [InImport]
+// CHECK:STDERR: api.carbon:6:1: note: name is previously declared here [NameDeclPrevious]
 // CHECK:STDERR: fn C(c: (i32,)) -> {.c: i32};
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 // CHECK:STDERR:
-// CHECK:STDERR: fail_merge.carbon:[[@LINE+18]]:1(InImport): in import
-// CHECK:STDERR: extern_api.carbon:7:1: error(NameDeclDuplicate): duplicate name being declared in the same scope
+// CHECK:STDERR: fail_merge.carbon:[[@LINE+18]]:1: in import [InImport]
+// CHECK:STDERR: extern_api.carbon:7:1: error: duplicate name being declared in the same scope [NameDeclDuplicate]
 // CHECK:STDERR: extern library "redecl_extern_api" fn D();
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-// CHECK:STDERR: fail_merge.carbon:[[@LINE+14]]:1(InImport): in import
-// CHECK:STDERR: api.carbon:7:1: note(NameDeclPrevious): name is previously declared here
+// CHECK:STDERR: fail_merge.carbon:[[@LINE+14]]:1: in import [InImport]
+// CHECK:STDERR: api.carbon:7:1: note: name is previously declared here [NameDeclPrevious]
 // CHECK:STDERR: extern fn D();
 // CHECK:STDERR: ^~~~~~~~~~~~~~
 // CHECK:STDERR:
-// CHECK:STDERR: fail_merge.carbon:[[@LINE+9]]:1(InImport): in import
-// CHECK:STDERR: extern_api.carbon:10:1: error(NameDeclDuplicate): duplicate name being declared in the same scope
+// CHECK:STDERR: fail_merge.carbon:[[@LINE+9]]:1: in import [InImport]
+// CHECK:STDERR: extern_api.carbon:10:1: error: duplicate name being declared in the same scope [NameDeclDuplicate]
 // CHECK:STDERR: extern library "redecl_extern_api" fn NS.E();
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-// CHECK:STDERR: fail_merge.carbon:[[@LINE+5]]:1(InImport): in import
-// CHECK:STDERR: api.carbon:10:1: note(NameDeclPrevious): name is previously declared here
+// CHECK:STDERR: fail_merge.carbon:[[@LINE+5]]:1: in import [InImport]
+// CHECK:STDERR: api.carbon:10:1: note: name is previously declared here [NameDeclPrevious]
 // CHECK:STDERR: fn NS.E();
 // CHECK:STDERR: ^~~~~~~~~~
 // CHECK:STDERR:
@@ -190,48 +190,48 @@ var e: () = NS.E();

 library "[[@TEST_NAME]]";

-// CHECK:STDERR: fail_merge_reverse.carbon:[[@LINE+44]]:1(InImport): in import
-// CHECK:STDERR: api.carbon:4:1: error(NameDeclDuplicate): duplicate name being declared in the same scope
+// CHECK:STDERR: fail_merge_reverse.carbon:[[@LINE+44]]:1: in import [InImport]
+// CHECK:STDERR: api.carbon:4:1: error: duplicate name being declared in the same scope [NameDeclDuplicate]
 // CHECK:STDERR: fn A();
 // CHECK:STDERR: ^~~~~~~
-// CHECK:STDERR: fail_merge_reverse.carbon:[[@LINE+40]]:1(InImport): in import
-// CHECK:STDERR: extern_api.carbon:4:1: note(NameDeclPrevious): name is previously declared here
+// CHECK:STDERR: fail_merge_reverse.carbon:[[@LINE+40]]:1: in import [InImport]
+// CHECK:STDERR: extern_api.carbon:4:1: note: name is previously declared here [NameDeclPrevious]
 // CHECK:STDERR: extern library "redecl_extern_api" fn A();
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 // CHECK:STDERR:
-// CHECK:STDERR: fail_merge_reverse.carbon:[[@LINE+35]]:1(InImport): in import
-// CHECK:STDERR: api.carbon:5:1: error(NameDeclDuplicate): duplicate name being declared in the same scope
+// CHECK:STDERR: fail_merge_reverse.carbon:[[@LINE+35]]:1: in import [InImport]
+// CHECK:STDERR: api.carbon:5:1: error: duplicate name being declared in the same scope [NameDeclDuplicate]
 // CHECK:STDERR: fn B(b: i32) -> i32;
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~
-// CHECK:STDERR: fail_merge_reverse.carbon:[[@LINE+31]]:1(InImport): in import
-// CHECK:STDERR: extern_api.carbon:5:1: note(NameDeclPrevious): name is previously declared here
+// CHECK:STDERR: fail_merge_reverse.carbon:[[@LINE+31]]:1: in import [InImport]
+// CHECK:STDERR: extern_api.carbon:5:1: note: name is previously declared here [NameDeclPrevious]
 // CHECK:STDERR: extern library "redecl_extern_api" fn B(b: i32) -> i32;
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 // CHECK:STDERR:
-// CHECK:STDERR: fail_merge_reverse.carbon:[[@LINE+26]]:1(InImport): in import
-// CHECK:STDERR: api.carbon:6:1: error(NameDeclDuplicate): duplicate name being declared in the same scope
+// CHECK:STDERR: fail_merge_reverse.carbon:[[@LINE+26]]:1: in import [InImport]
+// CHECK:STDERR: api.carbon:6:1: error: duplicate name being declared in the same scope [NameDeclDuplicate]
 // CHECK:STDERR: fn C(c: (i32,)) -> {.c: i32};
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-// CHECK:STDERR: fail_merge_reverse.carbon:[[@LINE+22]]:1(InImport): in import
-// CHECK:STDERR: extern_api.carbon:6:1: note(NameDeclPrevious): name is previously declared here
+// CHECK:STDERR: fail_merge_reverse.carbon:[[@LINE+22]]:1: in import [InImport]
+// CHECK:STDERR: extern_api.carbon:6:1: note: name is previously declared here [NameDeclPrevious]
 // CHECK:STDERR: extern library "redecl_extern_api" fn C(c: (i32,)) -> {.c: i32};
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 // CHECK:STDERR:
-// CHECK:STDERR: fail_merge_reverse.carbon:[[@LINE+17]]:1(InImport): in import
-// CHECK:STDERR: api.carbon:7:1: error(NameDeclDuplicate): duplicate name being declared in the same scope
+// CHECK:STDERR: fail_merge_reverse.carbon:[[@LINE+17]]:1: in import [InImport]
+// CHECK:STDERR: api.carbon:7:1: error: duplicate name being declared in the same scope [NameDeclDuplicate]
 // CHECK:STDERR: extern fn D();
 // CHECK:STDERR: ^~~~~~~~~~~~~~
-// CHECK:STDERR: fail_merge_reverse.carbon:[[@LINE+13]]:1(InImport): in import
-// CHECK:STDERR: extern_api.carbon:7:1: note(NameDeclPrevious): name is previously declared here
+// CHECK:STDERR: fail_merge_reverse.carbon:[[@LINE+13]]:1: in import [InImport]
+// CHECK:STDERR: extern_api.carbon:7:1: note: name is previously declared here [NameDeclPrevious]
 // CHECK:STDERR: extern library "redecl_extern_api" fn D();
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 // CHECK:STDERR:
-// CHECK:STDERR: fail_merge_reverse.carbon:[[@LINE+8]]:1(InImport): in import
-// CHECK:STDERR: api.carbon:10:1: error(NameDeclDuplicate): duplicate name being declared in the same scope
+// CHECK:STDERR: fail_merge_reverse.carbon:[[@LINE+8]]:1: in import [InImport]
+// CHECK:STDERR: api.carbon:10:1: error: duplicate name being declared in the same scope [NameDeclDuplicate]
 // CHECK:STDERR: fn NS.E();
 // CHECK:STDERR: ^~~~~~~~~~
-// CHECK:STDERR: fail_merge_reverse.carbon:[[@LINE+4]]:1(InImport): in import
-// CHECK:STDERR: extern_api.carbon:10:1: note(NameDeclPrevious): name is previously declared here
+// CHECK:STDERR: fail_merge_reverse.carbon:[[@LINE+4]]:1: in import [InImport]
+// CHECK:STDERR: extern_api.carbon:10:1: note: name is previously declared here [NameDeclPrevious]
 // CHECK:STDERR: extern library "redecl_extern_api" fn NS.E();
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 import library "extern_api";
@@ -25,10 +25,10 @@ var x: () = F();
 library "[[@TEST_NAME]]";

 extern fn F();
-// CHECK:STDERR: fail_redecl.carbon:[[@LINE+7]]:1: error(RedeclRedundant): redeclaration of `fn F` is redundant
+// CHECK:STDERR: fail_redecl.carbon:[[@LINE+7]]:1: error: redeclaration of `fn F` is redundant [RedeclRedundant]
 // CHECK:STDERR: extern fn F();
 // CHECK:STDERR: ^~~~~~~~~~~~~~
-// CHECK:STDERR: fail_redecl.carbon:[[@LINE-4]]:1: note(RedeclPrevDecl): previously declared here
+// CHECK:STDERR: fail_redecl.carbon:[[@LINE-4]]:1: note: previously declared here [RedeclPrevDecl]
 // CHECK:STDERR: extern fn F();
 // CHECK:STDERR: ^~~~~~~~~~~~~~
 // CHECK:STDERR:
@@ -39,10 +39,10 @@ extern fn F();
 library "[[@TEST_NAME]]";

 extern fn F();
-// CHECK:STDERR: fail_redecl_extern.carbon:[[@LINE+7]]:1: error(RedeclRedundant): redeclaration of `fn F` is redundant
+// CHECK:STDERR: fail_redecl_extern.carbon:[[@LINE+7]]:1: error: redeclaration of `fn F` is redundant [RedeclRedundant]
 // CHECK:STDERR: fn F();
 // CHECK:STDERR: ^~~~~~~
-// CHECK:STDERR: fail_redecl_extern.carbon:[[@LINE-4]]:1: note(RedeclPrevDecl): previously declared here
+// CHECK:STDERR: fail_redecl_extern.carbon:[[@LINE-4]]:1: note: previously declared here [RedeclPrevDecl]
 // CHECK:STDERR: extern fn F();
 // CHECK:STDERR: ^~~~~~~~~~~~~~
 // CHECK:STDERR:
@@ -53,12 +53,12 @@ fn F();
 library "[[@TEST_NAME]]";

 class C {
-  // CHECK:STDERR: fail_member_extern.carbon:[[@LINE+4]]:3: error(ModifierExternNotAllowed): `extern` not allowed; requires file or namespace scope
+  // CHECK:STDERR: fail_member_extern.carbon:[[@LINE+4]]:3: error: `extern` not allowed; requires file or namespace scope [ModifierExternNotAllowed]
  // CHECK:STDERR:   extern fn F();
  // CHECK:STDERR:   ^~~~~~
  // CHECK:STDERR:
  extern fn F();
-  // CHECK:STDERR: fail_member_extern.carbon:[[@LINE+3]]:3: error(ModifierExternNotAllowed): `extern` not allowed; requires file or namespace scope
+  // CHECK:STDERR: fail_member_extern.carbon:[[@LINE+3]]:3: error: `extern` not allowed; requires file or namespace scope [ModifierExternNotAllowed]
  // CHECK:STDERR:   extern fn G[self: Self]();
  // CHECK:STDERR:   ^~~~~~
  extern fn G[self: Self]();
@@ -28,11 +28,11 @@ library "[[@TEST_NAME]]";

 import library "extern_library";

-// CHECK:STDERR: fail_extern_library_nonowner.carbon:[[@LINE+8]]:1: error(ExternLibraryIncorrect): declaration in library "extern_library_nonowner" doesn't match `extern library` declaration
+// CHECK:STDERR: fail_extern_library_nonowner.carbon:[[@LINE+8]]:1: error: declaration in library "extern_library_nonowner" doesn't match `extern library` declaration [ExternLibraryIncorrect]
 // CHECK:STDERR: extern fn F();
 // CHECK:STDERR: ^~~~~~~~~~~~~~
-// CHECK:STDERR: fail_extern_library_nonowner.carbon:[[@LINE-5]]:1(InImport): in import
-// CHECK:STDERR: extern_library.carbon:4:1: note(ExternLibraryExpected): previously declared with `extern library` here
+// CHECK:STDERR: fail_extern_library_nonowner.carbon:[[@LINE-5]]:1: in import [InImport]
+// CHECK:STDERR: extern_library.carbon:4:1: note: previously declared with `extern library` here [ExternLibraryExpected]
 // CHECK:STDERR: extern library "extern_library_owner" fn F();
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 // CHECK:STDERR:
@@ -44,11 +44,11 @@ library "[[@TEST_NAME]]";

 import library "extern_library";

-// CHECK:STDERR: fail_extern_library_nonextern.carbon:[[@LINE+8]]:1: error(RedeclExternMismatch): redeclarations of `fn F` must match use of `extern`
+// CHECK:STDERR: fail_extern_library_nonextern.carbon:[[@LINE+8]]:1: error: redeclarations of `fn F` must match use of `extern` [RedeclExternMismatch]
 // CHECK:STDERR: fn F();
 // CHECK:STDERR: ^~~~~~~
-// CHECK:STDERR: fail_extern_library_nonextern.carbon:[[@LINE-5]]:1(InImport): in import
-// CHECK:STDERR: extern_library.carbon:4:1: note(RedeclPrevDecl): previously declared here
+// CHECK:STDERR: fail_extern_library_nonextern.carbon:[[@LINE-5]]:1: in import [InImport]
+// CHECK:STDERR: extern_library.carbon:4:1: note: previously declared here [RedeclPrevDecl]
 // CHECK:STDERR: extern library "extern_library_owner" fn F();
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 // CHECK:STDERR:
@@ -60,11 +60,11 @@ library "[[@TEST_NAME]]";

 import library "extern_library";

-// CHECK:STDERR: fail_extern_library_redecl.carbon:[[@LINE+8]]:1: error(ExternLibraryIncorrect): declaration in library "extern_library_redecl" doesn't match `extern library` declaration
+// CHECK:STDERR: fail_extern_library_redecl.carbon:[[@LINE+8]]:1: error: declaration in library "extern_library_redecl" doesn't match `extern library` declaration [ExternLibraryIncorrect]
 // CHECK:STDERR: extern library "extern_library_owner" fn F();
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-// CHECK:STDERR: fail_extern_library_redecl.carbon:[[@LINE-5]]:1(InImport): in import
-// CHECK:STDERR: extern_library.carbon:4:1: note(ExternLibraryExpected): previously declared with `extern library` here
+// CHECK:STDERR: fail_extern_library_redecl.carbon:[[@LINE-5]]:1: in import [InImport]
+// CHECK:STDERR: extern_library.carbon:4:1: note: previously declared with `extern library` here [ExternLibraryExpected]
 // CHECK:STDERR: extern library "extern_library_owner" fn F();
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 // CHECK:STDERR:
@@ -80,12 +80,12 @@ extern library "extern_library_owner" fn F();

 library "[[@TEST_NAME]]";

-// CHECK:STDERR: fail_extern_library_collision.carbon:[[@LINE+9]]:1(InImport): in import
-// CHECK:STDERR: extern_library_copy.carbon:4:1: error(NameDeclDuplicate): duplicate name being declared in the same scope
+// CHECK:STDERR: fail_extern_library_collision.carbon:[[@LINE+9]]:1: in import [InImport]
+// CHECK:STDERR: extern_library_copy.carbon:4:1: error: duplicate name being declared in the same scope [NameDeclDuplicate]
 // CHECK:STDERR: extern library "extern_library_owner" fn F();
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-// CHECK:STDERR: fail_extern_library_collision.carbon:[[@LINE+5]]:1(InImport): in import
-// CHECK:STDERR: extern_library.carbon:4:1: note(NameDeclPrevious): name is previously declared here
+// CHECK:STDERR: fail_extern_library_collision.carbon:[[@LINE+5]]:1: in import [InImport]
+// CHECK:STDERR: extern_library.carbon:4:1: note: name is previously declared here [NameDeclPrevious]
 // CHECK:STDERR: extern library "extern_library_owner" fn F();
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 // CHECK:STDERR:
@@ -104,7 +104,7 @@ library "[[@TEST_NAME]]";

 import library "extern_library_mismatch"

-// CHECK:STDERR: fail_extern_library_mismatch_owner.carbon:[[@LINE+4]]:1: error(ExpectedDeclSemi): `import` declarations must end with a `;`
+// CHECK:STDERR: fail_extern_library_mismatch_owner.carbon:[[@LINE+4]]:1: error: `import` declarations must end with a `;` [ExpectedDeclSemi]
 // CHECK:STDERR: extern fn F();
 // CHECK:STDERR: ^~~~~~
 // CHECK:STDERR:
@@ -114,7 +114,7 @@ extern fn F();

 library "[[@TEST_NAME]]";

-// CHECK:STDERR: fail_extern_self_library.carbon:[[@LINE+4]]:1: error(ExternLibraryIsCurrentLibrary): `extern library` cannot specify the current library
+// CHECK:STDERR: fail_extern_self_library.carbon:[[@LINE+4]]:1: error: `extern library` cannot specify the current library [ExternLibraryIsCurrentLibrary]
 // CHECK:STDERR: extern library "extern_self_library" fn F();
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 // CHECK:STDERR:
@@ -132,11 +132,11 @@ library "[[@TEST_NAME]]";

 import library "extern_of_import";

-// CHECK:STDERR: fail_extern_of_import_redecl.carbon:[[@LINE+7]]:1: error(RedeclExternMismatch): redeclarations of `fn F` must match use of `extern`
+// CHECK:STDERR: fail_extern_of_import_redecl.carbon:[[@LINE+7]]:1: error: redeclarations of `fn F` must match use of `extern` [RedeclExternMismatch]
 // CHECK:STDERR: extern library "extern_of_import" fn F();
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-// CHECK:STDERR: fail_extern_of_import_redecl.carbon:[[@LINE-5]]:1(InImport): in import
-// CHECK:STDERR: extern_of_import.carbon:4:1: note(RedeclPrevDecl): previously declared here
+// CHECK:STDERR: fail_extern_of_import_redecl.carbon:[[@LINE-5]]:1: in import [InImport]
+// CHECK:STDERR: extern_of_import.carbon:4:1: note: previously declared here [RedeclPrevDecl]
 // CHECK:STDERR: fn F();
 // CHECK:STDERR: ^~~~~~~
 extern library "extern_of_import" fn F();
@@ -28,11 +28,11 @@ package Foo library "[[@TEST_NAME]]";

 import library default;

-// CHECK:STDERR: fail_wrong_library.carbon:[[@LINE+7]]:1: error(ExternLibraryIncorrect): declaration in library "wrong_library" doesn't match `extern library` declaration
+// CHECK:STDERR: fail_wrong_library.carbon:[[@LINE+7]]:1: error: declaration in library "wrong_library" doesn't match `extern library` declaration [ExternLibraryIncorrect]
 // CHECK:STDERR: extern fn F();
 // CHECK:STDERR: ^~~~~~~~~~~~~~
-// CHECK:STDERR: fail_wrong_library.carbon:[[@LINE-5]]:1(InImport): in import
-// CHECK:STDERR: default.carbon:4:1: note(ExternLibraryExpected): previously declared with `extern library` here
+// CHECK:STDERR: fail_wrong_library.carbon:[[@LINE-5]]:1: in import [InImport]
+// CHECK:STDERR: default.carbon:4:1: note: previously declared with `extern library` here [ExternLibraryExpected]
 // CHECK:STDERR: extern library "expected" fn F();
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 extern fn F();
@@ -26,11 +26,11 @@ library "[[@TEST_NAME]]";

 import library "extern_library";

-// CHECK:STDERR: fail_wrong_library.carbon:[[@LINE+7]]:1: error(ExternLibraryIncorrect): declaration in library "wrong_library" doesn't match `extern library` declaration
+// CHECK:STDERR: fail_wrong_library.carbon:[[@LINE+7]]:1: error: declaration in library "wrong_library" doesn't match `extern library` declaration [ExternLibraryIncorrect]
 // CHECK:STDERR: extern fn F();
 // CHECK:STDERR: ^~~~~~~~~~~~~~
-// CHECK:STDERR: fail_wrong_library.carbon:[[@LINE-5]]:1(InImport): in import
-// CHECK:STDERR: extern_library.carbon:4:1: note(ExternLibraryExpected): previously declared with `extern library` here
+// CHECK:STDERR: fail_wrong_library.carbon:[[@LINE-5]]:1: in import [InImport]
+// CHECK:STDERR: extern_library.carbon:4:1: note: previously declared with `extern library` here [ExternLibraryExpected]
 // CHECK:STDERR: extern library default fn F();
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 extern fn F();
@@ -21,24 +21,24 @@ fn ReturnDUnused() -> D;
 fn ReturnDUsed() -> D;

 fn Call() {
-  // CHECK:STDERR: fail_incomplete_return.carbon:[[@LINE+10]]:3: error(IncompleteTypeInFunctionReturnType): function returns incomplete type `C`
+  // CHECK:STDERR: fail_incomplete_return.carbon:[[@LINE+10]]:3: error: function returns incomplete type `C` [IncompleteTypeInFunctionReturnType]
  // CHECK:STDERR:   ReturnCUsed();
  // CHECK:STDERR:   ^~~~~~~~~~~
-  // CHECK:STDERR: fail_incomplete_return.carbon:[[@LINE-12]]:1: note(ClassForwardDeclaredHere): class was forward declared here
+  // CHECK:STDERR: fail_incomplete_return.carbon:[[@LINE-12]]:1: note: class was forward declared here [ClassForwardDeclaredHere]
  // CHECK:STDERR: class C;
  // CHECK:STDERR: ^~~~~~~~
-  // CHECK:STDERR: fail_incomplete_return.carbon:[[@LINE-11]]:18: note(IncompleteReturnTypeHere): return type declared here
+  // CHECK:STDERR: fail_incomplete_return.carbon:[[@LINE-11]]:18: note: return type declared here [IncompleteReturnTypeHere]
  // CHECK:STDERR: fn ReturnCUsed() -> C;
  // CHECK:STDERR:                  ^~~~
  // CHECK:STDERR:
  ReturnCUsed();
-  // CHECK:STDERR: fail_incomplete_return.carbon:[[@LINE+10]]:3: error(IncompleteTypeInFunctionReturnType): function returns incomplete type `D`
+  // CHECK:STDERR: fail_incomplete_return.carbon:[[@LINE+10]]:3: error: function returns incomplete type `D` [IncompleteTypeInFunctionReturnType]
  // CHECK:STDERR:   ReturnDUsed();
  // CHECK:STDERR:   ^~~~~~~~~~~
-  // CHECK:STDERR: fail_incomplete_return.carbon:[[@LINE-22]]:1: note(ClassForwardDeclaredHere): class was forward declared here
+  // CHECK:STDERR: fail_incomplete_return.carbon:[[@LINE-22]]:1: note: class was forward declared here [ClassForwardDeclaredHere]
  // CHECK:STDERR: class D;
  // CHECK:STDERR: ^~~~~~~~
-  // CHECK:STDERR: fail_incomplete_return.carbon:[[@LINE-20]]:18: note(IncompleteReturnTypeHere): return type declared here
+  // CHECK:STDERR: fail_incomplete_return.carbon:[[@LINE-20]]:18: note: return type declared here [IncompleteReturnTypeHere]
  // CHECK:STDERR: fn ReturnDUsed() -> D;
  // CHECK:STDERR:                  ^~~~
  // CHECK:STDERR:
@@ -54,28 +54,28 @@ library "[[@TEST_NAME]]";
 import library "incomplete_return";

 fn CallFAndGIncomplete() {
-  // CHECK:STDERR: fail_use_imported.carbon:[[@LINE+12]]:3: error(IncompleteTypeInFunctionReturnType): function returns incomplete type `C`
+  // CHECK:STDERR: fail_use_imported.carbon:[[@LINE+12]]:3: error: function returns incomplete type `C` [IncompleteTypeInFunctionReturnType]
  // CHECK:STDERR:   ReturnCUnused();
  // CHECK:STDERR:   ^~~~~~~~~~~~~
-  // CHECK:STDERR: fail_use_imported.carbon:[[@LINE-6]]:1(InImport): in import
-  // CHECK:STDERR: fail_incomplete_return.carbon:4:1: note(ClassForwardDeclaredHere): class was forward declared here
+  // CHECK:STDERR: fail_use_imported.carbon:[[@LINE-6]]:1: in import [InImport]
+  // CHECK:STDERR: fail_incomplete_return.carbon:4:1: note: class was forward declared here [ClassForwardDeclaredHere]
  // CHECK:STDERR: class C;
  // CHECK:STDERR: ^~~~~~~~
-  // CHECK:STDERR: fail_use_imported.carbon:[[@LINE-10]]:1(InImport): in import
-  // CHECK:STDERR: fail_incomplete_return.carbon:7:20: note(IncompleteReturnTypeHere): return type declared here
+  // CHECK:STDERR: fail_use_imported.carbon:[[@LINE-10]]:1: in import [InImport]
+  // CHECK:STDERR: fail_incomplete_return.carbon:7:20: note: return type declared here [IncompleteReturnTypeHere]
  // CHECK:STDERR: fn ReturnCUnused() -> C;
  // CHECK:STDERR:                    ^~~~
  // CHECK:STDERR:
  ReturnCUnused();
-  // CHECK:STDERR: fail_use_imported.carbon:[[@LINE+11]]:3: error(IncompleteTypeInFunctionReturnType): function returns incomplete type `C`
+  // CHECK:STDERR: fail_use_imported.carbon:[[@LINE+11]]:3: error: function returns incomplete type `C` [IncompleteTypeInFunctionReturnType]
  // CHECK:STDERR:   ReturnCUsed();
  // CHECK:STDERR:   ^~~~~~~~~~~
-  // CHECK:STDERR: fail_use_imported.carbon:[[@LINE-19]]:1(InImport): in import
-  // CHECK:STDERR: fail_incomplete_return.carbon:4:1: note(ClassForwardDeclaredHere): class was forward declared here
+  // CHECK:STDERR: fail_use_imported.carbon:[[@LINE-19]]:1: in import [InImport]
+  // CHECK:STDERR: fail_incomplete_return.carbon:4:1: note: class was forward declared here [ClassForwardDeclaredHere]
  // CHECK:STDERR: class C;
  // CHECK:STDERR: ^~~~~~~~
-  // CHECK:STDERR: fail_use_imported.carbon:[[@LINE-23]]:1(InImport): in import
-  // CHECK:STDERR: fail_incomplete_return.carbon:8:18: note(IncompleteReturnTypeHere): return type declared here
+  // CHECK:STDERR: fail_use_imported.carbon:[[@LINE-23]]:1: in import [InImport]
+  // CHECK:STDERR: fail_incomplete_return.carbon:8:18: note: return type declared here [IncompleteReturnTypeHere]
  // CHECK:STDERR: fn ReturnCUsed() -> C;
  // CHECK:STDERR:                  ^~~~
  ReturnCUsed();
@@ -8,84 +8,84 @@
 // TIP: To dump output, run:
 // TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/function/declaration/no_prelude/fail_modifiers.carbon

-// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+11]]:1: error(ModifierRequiresInterface): `default` not allowed; requires interface scope
+// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+11]]:1: error: `default` not allowed; requires interface scope [ModifierRequiresInterface]
 // CHECK:STDERR: default protected fn WrongOrder();
 // CHECK:STDERR: ^~~~~~~
 // CHECK:STDERR:
-// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+7]]:9: error(ModifierMustAppearBefore): `protected` must appear before `default`
+// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+7]]:9: error: `protected` must appear before `default` [ModifierMustAppearBefore]
 // CHECK:STDERR: default protected fn WrongOrder();
 // CHECK:STDERR:         ^~~~~~~~~
-// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+4]]:1: note(ModifierPrevious): `default` previously appeared here
+// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+4]]:1: note: `default` previously appeared here [ModifierPrevious]
 // CHECK:STDERR: default protected fn WrongOrder();
 // CHECK:STDERR: ^~~~~~~
 // CHECK:STDERR:
 default protected fn WrongOrder();

-// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+11]]:1: error(ModifierRequiresClass): `virtual` not allowed; requires class scope
+// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+11]]:1: error: `virtual` not allowed; requires class scope [ModifierRequiresClass]
 // CHECK:STDERR: virtual virtual fn DuplicateVirtual() {}
 // CHECK:STDERR: ^~~~~~~
 // CHECK:STDERR:
-// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+7]]:9: error(ModifierRepeated): `virtual` repeated on declaration
+// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+7]]:9: error: `virtual` repeated on declaration [ModifierRepeated]
 // CHECK:STDERR: virtual virtual fn DuplicateVirtual() {}
 // CHECK:STDERR:         ^~~~~~~
-// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+4]]:1: note(ModifierPrevious): `virtual` previously appeared here
+// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+4]]:1: note: `virtual` previously appeared here [ModifierPrevious]
 // CHECK:STDERR: virtual virtual fn DuplicateVirtual() {}
 // CHECK:STDERR: ^~~~~~~
 // CHECK:STDERR:
 virtual virtual fn DuplicateVirtual() {}

-// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+7]]:9: error(ModifierNotAllowedWith): `protected` not allowed on declaration with `private`
+// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+7]]:9: error: `protected` not allowed on declaration with `private` [ModifierNotAllowedWith]
 // CHECK:STDERR: private protected fn TwoAccess();
 // CHECK:STDERR:         ^~~~~~~~~
-// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+4]]:1: note(ModifierPrevious): `private` previously appeared here
+// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+4]]:1: note: `private` previously appeared here [ModifierPrevious]
 // CHECK:STDERR: private protected fn TwoAccess();
 // CHECK:STDERR: ^~~~~~~
 // CHECK:STDERR:
 private protected fn TwoAccess();

-// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+11]]:1: error(ModifierRequiresClass): `abstract` not allowed; requires class scope
+// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+11]]:1: error: `abstract` not allowed; requires class scope [ModifierRequiresClass]
 // CHECK:STDERR: abstract virtual fn ModifiersConflict() {}
 // CHECK:STDERR: ^~~~~~~~
 // CHECK:STDERR:
-// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+7]]:10: error(ModifierNotAllowedWith): `virtual` not allowed on declaration with `abstract`
+// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+7]]:10: error: `virtual` not allowed on declaration with `abstract` [ModifierNotAllowedWith]
 // CHECK:STDERR: abstract virtual fn ModifiersConflict() {}
 // CHECK:STDERR:          ^~~~~~~
-// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+4]]:1: note(ModifierPrevious): `abstract` previously appeared here
+// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+4]]:1: note: `abstract` previously appeared here [ModifierPrevious]
 // CHECK:STDERR: abstract virtual fn ModifiersConflict() {}
 // CHECK:STDERR: ^~~~~~~~
 // CHECK:STDERR:
 abstract virtual fn ModifiersConflict() {}

-// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+4]]:1: error(ModifierNotAllowedOnDeclaration): `base` not allowed on `fn` declaration
+// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+4]]:1: error: `base` not allowed on `fn` declaration [ModifierNotAllowedOnDeclaration]
 // CHECK:STDERR: base fn InvalidModifier();
 // CHECK:STDERR: ^~~~
 // CHECK:STDERR:
 base fn InvalidModifier();

-// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+18]]:1: error(ModifierRequiresInterface): `default` not allowed; requires interface scope
+// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+18]]:1: error: `default` not allowed; requires interface scope [ModifierRequiresInterface]
 // CHECK:STDERR: default final virtual fn ModifiersConflict2() {}
 // CHECK:STDERR: ^~~~~~~
 // CHECK:STDERR:
-// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+14]]:9: error(ModifierNotAllowedWith): `final` not allowed on declaration with `default`
+// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+14]]:9: error: `final` not allowed on declaration with `default` [ModifierNotAllowedWith]
 // CHECK:STDERR: default final virtual fn ModifiersConflict2() {}
 // CHECK:STDERR:         ^~~~~
-// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+11]]:1: note(ModifierPrevious): `default` previously appeared here
+// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+11]]:1: note: `default` previously appeared here [ModifierPrevious]
 // CHECK:STDERR: default final virtual fn ModifiersConflict2() {}
 // CHECK:STDERR: ^~~~~~~
 // CHECK:STDERR:
-// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+7]]:15: error(ModifierNotAllowedWith): `virtual` not allowed on declaration with `default`
+// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+7]]:15: error: `virtual` not allowed on declaration with `default` [ModifierNotAllowedWith]
 // CHECK:STDERR: default final virtual fn ModifiersConflict2() {}
 // CHECK:STDERR:               ^~~~~~~
-// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+4]]:1: note(ModifierPrevious): `default` previously appeared here
+// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+4]]:1: note: `default` previously appeared here [ModifierPrevious]
 // CHECK:STDERR: default final virtual fn ModifiersConflict2() {}
 // CHECK:STDERR: ^~~~~~~
 // CHECK:STDERR:
 default final virtual fn ModifiersConflict2() {}

-// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+6]]:8: error(ModifierMustAppearBefore): `private` must appear before `extern`
+// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+6]]:8: error: `private` must appear before `extern` [ModifierMustAppearBefore]
 // CHECK:STDERR: extern private fn ExternOrderAndConflict() {}
 // CHECK:STDERR:        ^~~~~~~
-// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+3]]:1: note(ModifierPrevious): `extern` previously appeared here
+// CHECK:STDERR: fail_modifiers.carbon:[[@LINE+3]]:1: note: `extern` previously appeared here [ModifierPrevious]
 // CHECK:STDERR: extern private fn ExternOrderAndConflict() {}
 // CHECK:STDERR: ^~~~~~
 extern private fn ExternOrderAndConflict() {}
@@ -8,11 +8,11 @@
 // TIP: To dump output, run:
 // TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/function/declaration/no_prelude/fail_pattern_in_signature.carbon

-// CHECK:STDERR: fail_pattern_in_signature.carbon:[[@LINE+7]]:6: error(ExpectedBindingPattern): expected name in binding pattern
+// CHECK:STDERR: fail_pattern_in_signature.carbon:[[@LINE+7]]:6: error: expected name in binding pattern [ExpectedBindingPattern]
 // CHECK:STDERR: fn F((a: {}, b: {}), c: {});
 // CHECK:STDERR:      ^
 // CHECK:STDERR:
-// CHECK:STDERR: fail_pattern_in_signature.carbon:[[@LINE+3]]:6: error(SemanticsTodo): semantics TODO: `Error recovery from keyword name.`
+// CHECK:STDERR: fail_pattern_in_signature.carbon:[[@LINE+3]]:6: error: semantics TODO: `Error recovery from keyword name.` [SemanticsTodo]
 // CHECK:STDERR: fn F((a: {}, b: {}), c: {});
 // CHECK:STDERR:      ^
 fn F((a: {}, b: {}), c: {});
@@ -9,50 +9,50 @@
 // TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/function/declaration/no_prelude/fail_redecl.carbon

 fn A();
-// CHECK:STDERR: fail_redecl.carbon:[[@LINE+7]]:1: error(RedeclRedundant): redeclaration of `fn A` is redundant
+// CHECK:STDERR: fail_redecl.carbon:[[@LINE+7]]:1: error: redeclaration of `fn A` is redundant [RedeclRedundant]
 // CHECK:STDERR: fn A();
 // CHECK:STDERR: ^~~~~~~
-// CHECK:STDERR: fail_redecl.carbon:[[@LINE-4]]:1: note(RedeclPrevDecl): previously declared here
+// CHECK:STDERR: fail_redecl.carbon:[[@LINE-4]]:1: note: previously declared here [RedeclPrevDecl]
 // CHECK:STDERR: fn A();
 // CHECK:STDERR: ^~~~~~~
 // CHECK:STDERR:
 fn A();

 fn B(x: ());
-// CHECK:STDERR: fail_redecl.carbon:[[@LINE+7]]:1: error(RedeclRedundant): redeclaration of `fn B` is redundant
+// CHECK:STDERR: fail_redecl.carbon:[[@LINE+7]]:1: error: redeclaration of `fn B` is redundant [RedeclRedundant]
 // CHECK:STDERR: fn B(x: ());
 // CHECK:STDERR: ^~~~~~~~~~~~
-// CHECK:STDERR: fail_redecl.carbon:[[@LINE-4]]:1: note(RedeclPrevDecl): previously declared here
+// CHECK:STDERR: fail_redecl.carbon:[[@LINE-4]]:1: note: previously declared here [RedeclPrevDecl]
 // CHECK:STDERR: fn B(x: ());
 // CHECK:STDERR: ^~~~~~~~~~~~
 // CHECK:STDERR:
 fn B(x: ());

 fn C();
-// CHECK:STDERR: fail_redecl.carbon:[[@LINE+7]]:1: error(RedeclParamCountDiffers): redeclaration differs because of parameter count of 1
+// CHECK:STDERR: fail_redecl.carbon:[[@LINE+7]]:1: error: redeclaration differs because of parameter count of 1 [RedeclParamCountDiffers]
 // CHECK:STDERR: fn C(x: ());
 // CHECK:STDERR: ^~~~~~~~~~~~
-// CHECK:STDERR: fail_redecl.carbon:[[@LINE-4]]:1: note(RedeclParamCountPrevious): previously declared with parameter count of 0
+// CHECK:STDERR: fail_redecl.carbon:[[@LINE-4]]:1: note: previously declared with parameter count of 0 [RedeclParamCountPrevious]
 // CHECK:STDERR: fn C();
 // CHECK:STDERR: ^~~~~~~
 // CHECK:STDERR:
 fn C(x: ());

 fn D() {}
-// CHECK:STDERR: fail_redecl.carbon:[[@LINE+7]]:1: error(RedeclRedundant): redeclaration of `fn D` is redundant
+// CHECK:STDERR: fail_redecl.carbon:[[@LINE+7]]:1: error: redeclaration of `fn D` is redundant [RedeclRedundant]
 // CHECK:STDERR: fn D();
 // CHECK:STDERR: ^~~~~~~
-// CHECK:STDERR: fail_redecl.carbon:[[@LINE-4]]:1: note(RedeclPrevDecl): previously declared here
+// CHECK:STDERR: fail_redecl.carbon:[[@LINE-4]]:1: note: previously declared here [RedeclPrevDecl]
 // CHECK:STDERR: fn D() {}
 // CHECK:STDERR: ^~~~~~~~
 // CHECK:STDERR:
 fn D();

 fn E() {}
-// CHECK:STDERR: fail_redecl.carbon:[[@LINE+6]]:1: error(RedeclRedef): redefinition of `fn E`
+// CHECK:STDERR: fail_redecl.carbon:[[@LINE+6]]:1: error: redefinition of `fn E` [RedeclRedef]
 // CHECK:STDERR: fn E() {}
 // CHECK:STDERR: ^~~~~~~~
-// CHECK:STDERR: fail_redecl.carbon:[[@LINE-4]]:1: note(RedeclPrevDef): previously defined here
+// CHECK:STDERR: fail_redecl.carbon:[[@LINE-4]]:1: note: previously defined here [RedeclPrevDef]
 // CHECK:STDERR: fn E() {}
 // CHECK:STDERR: ^~~~~~~~
 fn E() {}
@@ -11,7 +11,7 @@
 // --- fail_no_body.carbon

 library "[[@TEST_NAME]]";
-// CHECK:STDERR: fail_no_body.carbon:[[@LINE+4]]:1: error(SemanticsTodo): semantics TODO: `function with positional parameters`
+// CHECK:STDERR: fail_no_body.carbon:[[@LINE+4]]:1: error: semantics TODO: `function with positional parameters` [SemanticsTodo]
 // CHECK:STDERR: fn A;
 // CHECK:STDERR: ^~~~~
 // CHECK:STDERR:
@@ -20,7 +20,7 @@ fn A;
 // --- fail_todo_brace_body.carbon

 library "[[@TEST_NAME]]";
-// CHECK:STDERR: fail_todo_brace_body.carbon:[[@LINE+4]]:1: error(SemanticsTodo): semantics TODO: `function with positional parameters`
+// CHECK:STDERR: fail_todo_brace_body.carbon:[[@LINE+4]]:1: error: semantics TODO: `function with positional parameters` [SemanticsTodo]
 // CHECK:STDERR: fn A {
 // CHECK:STDERR: ^~~~~~
 // CHECK:STDERR:
@@ -31,11 +31,11 @@ fn A {

 // TODO: We don't have parsing support for this yet.
 library "[[@TEST_NAME]]";
-// CHECK:STDERR: fail_todo_arrow_body.carbon:[[@LINE+7]]:1: error(SemanticsTodo): semantics TODO: `function with positional parameters`
+// CHECK:STDERR: fail_todo_arrow_body.carbon:[[@LINE+7]]:1: error: semantics TODO: `function with positional parameters` [SemanticsTodo]
 // CHECK:STDERR: fn A => 0;
 // CHECK:STDERR: ^~~~~~~~~~
 // CHECK:STDERR:
-// CHECK:STDERR: fail_todo_arrow_body.carbon:[[@LINE+3]]:6: error(ExpectedDeclSemiOrDefinition): `fn` declarations must either end with a `;` or have a `{ ... }` block for a definition
+// CHECK:STDERR: fail_todo_arrow_body.carbon:[[@LINE+3]]:6: error: `fn` declarations must either end with a `;` or have a `{ ... }` block for a definition [ExpectedDeclSemiOrDefinition]
 // CHECK:STDERR: fn A => 0;
 // CHECK:STDERR:      ^~
 fn A => 0;
@@ -30,15 +30,15 @@ extern fn A();

 impl library "[[@TEST_NAME]]";

-// CHECK:STDERR: fail_extern_api.impl.carbon:[[@LINE+12]]:1: error(RedeclExternMismatch): redeclarations of `fn A` must match use of `extern`
+// CHECK:STDERR: fail_extern_api.impl.carbon:[[@LINE+12]]:1: error: redeclarations of `fn A` must match use of `extern` [RedeclExternMismatch]
 // CHECK:STDERR: fn A();
 // CHECK:STDERR: ^~~~~~~
-// CHECK:STDERR: fail_extern_api.impl.carbon:[[@LINE-5]]:6(InImport): in import
-// CHECK:STDERR: extern_api.carbon:4:1: note(RedeclPrevDecl): previously declared here
+// CHECK:STDERR: fail_extern_api.impl.carbon:[[@LINE-5]]:6: in import [InImport]
+// CHECK:STDERR: extern_api.carbon:4:1: note: previously declared here [RedeclPrevDecl]
 // CHECK:STDERR: extern fn A();
 // CHECK:STDERR: ^~~~~~~~~~~~~~
 // CHECK:STDERR:
-// CHECK:STDERR: fail_extern_api.impl.carbon:[[@LINE+4]]:1: error(MissingDefinitionInImpl): no definition found for declaration in impl file
+// CHECK:STDERR: fail_extern_api.impl.carbon:[[@LINE+4]]:1: error: no definition found for declaration in impl file [MissingDefinitionInImpl]
 // CHECK:STDERR: fn A();
 // CHECK:STDERR: ^~~~~~~
 // CHECK:STDERR:
@@ -54,11 +54,11 @@ fn A();

 impl library "[[@TEST_NAME]]";

-// CHECK:STDERR: fail_extern_impl.impl.carbon:[[@LINE+7]]:1: error(RedeclExternMismatch): redeclarations of `fn A` must match use of `extern`
+// CHECK:STDERR: fail_extern_impl.impl.carbon:[[@LINE+7]]:1: error: redeclarations of `fn A` must match use of `extern` [RedeclExternMismatch]
 // CHECK:STDERR: extern fn A();
 // CHECK:STDERR: ^~~~~~~~~~~~~~
-// CHECK:STDERR: fail_extern_impl.impl.carbon:[[@LINE-5]]:6(InImport): in import
-// CHECK:STDERR: extern_impl.carbon:4:1: note(RedeclPrevDecl): previously declared here
+// CHECK:STDERR: fail_extern_impl.impl.carbon:[[@LINE-5]]:6: in import [InImport]
+// CHECK:STDERR: extern_impl.carbon:4:1: note: previously declared here [RedeclPrevDecl]
 // CHECK:STDERR: fn A();
 // CHECK:STDERR: ^~~~~~~
 extern fn A();
@@ -52,7 +52,7 @@ fn C();

 impl library "[[@TEST_NAME]]";

-// CHECK:STDERR: fail_decl_in_api_decl_in_impl.impl.carbon:[[@LINE+4]]:1: error(MissingDefinitionInImpl): no definition found for declaration in impl file
+// CHECK:STDERR: fail_decl_in_api_decl_in_impl.impl.carbon:[[@LINE+4]]:1: error: no definition found for declaration in impl file [MissingDefinitionInImpl]
 // CHECK:STDERR: fn C();
 // CHECK:STDERR: ^~~~~~~
 // CHECK:STDERR:
@@ -66,7 +66,7 @@ library "[[@TEST_NAME]]";

 impl library "[[@TEST_NAME]]";

-// CHECK:STDERR: fail_decl_only_in_impl.impl.carbon:[[@LINE+3]]:1: error(MissingDefinitionInImpl): no definition found for declaration in impl file
+// CHECK:STDERR: fail_decl_only_in_impl.impl.carbon:[[@LINE+3]]:1: error: no definition found for declaration in impl file [MissingDefinitionInImpl]
 // CHECK:STDERR: fn D();
 // CHECK:STDERR: ^~~~~~~
 fn D();
@@ -47,20 +47,20 @@ library "[[@TEST_NAME]]";

 import library "fns";

-// CHECK:STDERR: fail_def_ownership.carbon:[[@LINE+8]]:1: error(RedeclRedundant): redeclaration of `fn A` is redundant
+// CHECK:STDERR: fail_def_ownership.carbon:[[@LINE+8]]:1: error: redeclaration of `fn A` is redundant [RedeclRedundant]
 // CHECK:STDERR: fn A() {};
 // CHECK:STDERR: ^~~~~~~~
-// CHECK:STDERR: fail_def_ownership.carbon:[[@LINE-5]]:1(InImport): in import
-// CHECK:STDERR: fns.carbon:4:1: note(RedeclPrevDecl): previously declared here
+// CHECK:STDERR: fail_def_ownership.carbon:[[@LINE-5]]:1: in import [InImport]
+// CHECK:STDERR: fns.carbon:4:1: note: previously declared here [RedeclPrevDecl]
 // CHECK:STDERR: fn A() {}
 // CHECK:STDERR: ^~~~~~~~
 // CHECK:STDERR:
 fn A() {};
-// CHECK:STDERR: fail_def_ownership.carbon:[[@LINE+8]]:1: error(RedeclRedundant): redeclaration of `fn B` is redundant
+// CHECK:STDERR: fail_def_ownership.carbon:[[@LINE+8]]:1: error: redeclaration of `fn B` is redundant [RedeclRedundant]
 // CHECK:STDERR: fn B(b: i32) -> i32;
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~
-// CHECK:STDERR: fail_def_ownership.carbon:[[@LINE-14]]:1(InImport): in import
-// CHECK:STDERR: fns.carbon:5:1: note(RedeclPrevDecl): previously declared here
+// CHECK:STDERR: fail_def_ownership.carbon:[[@LINE-14]]:1: in import [InImport]
+// CHECK:STDERR: fns.carbon:5:1: note: previously declared here [RedeclPrevDecl]
 // CHECK:STDERR: fn B(b: i32) -> i32 { return b; }
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~
 // CHECK:STDERR:
@@ -72,21 +72,21 @@ library "[[@TEST_NAME]]";

 import library "extern";

-// CHECK:STDERR: fail_redecl_then_def.carbon:[[@LINE+8]]:1: error(RedeclExternMismatch): redeclarations of `fn A` must match use of `extern`
+// CHECK:STDERR: fail_redecl_then_def.carbon:[[@LINE+8]]:1: error: redeclarations of `fn A` must match use of `extern` [RedeclExternMismatch]
 // CHECK:STDERR: fn A();
 // CHECK:STDERR: ^~~~~~~
-// CHECK:STDERR: fail_redecl_then_def.carbon:[[@LINE-5]]:1(InImport): in import
-// CHECK:STDERR: extern.carbon:4:1: note(RedeclPrevDecl): previously declared here
+// CHECK:STDERR: fail_redecl_then_def.carbon:[[@LINE-5]]:1: in import [InImport]
+// CHECK:STDERR: extern.carbon:4:1: note: previously declared here [RedeclPrevDecl]
 // CHECK:STDERR: extern fn A();
 // CHECK:STDERR: ^~~~~~~~~~~~~~
 // CHECK:STDERR:
 fn A();

-// CHECK:STDERR: fail_redecl_then_def.carbon:[[@LINE+8]]:1: error(RedeclExternMismatch): redeclarations of `fn A` must match use of `extern`
+// CHECK:STDERR: fail_redecl_then_def.carbon:[[@LINE+8]]:1: error: redeclarations of `fn A` must match use of `extern` [RedeclExternMismatch]
 // CHECK:STDERR: fn A() {}
 // CHECK:STDERR: ^~~~~~~~
-// CHECK:STDERR: fail_redecl_then_def.carbon:[[@LINE-15]]:1(InImport): in import
-// CHECK:STDERR: extern.carbon:4:1: note(RedeclPrevDecl): previously declared here
+// CHECK:STDERR: fail_redecl_then_def.carbon:[[@LINE-15]]:1: in import [InImport]
+// CHECK:STDERR: extern.carbon:4:1: note: previously declared here [RedeclPrevDecl]
 // CHECK:STDERR: extern fn A();
 // CHECK:STDERR: ^~~~~~~~~~~~~~
 // CHECK:STDERR:
@@ -98,11 +98,11 @@ library "[[@TEST_NAME]]";

 import library "fns";

-// CHECK:STDERR: fail_mix_extern_decl.carbon:[[@LINE+7]]:1: error(RedeclExternMismatch): redeclarations of `fn D` must match use of `extern`
+// CHECK:STDERR: fail_mix_extern_decl.carbon:[[@LINE+7]]:1: error: redeclarations of `fn D` must match use of `extern` [RedeclExternMismatch]
 // CHECK:STDERR: extern fn D();
 // CHECK:STDERR: ^~~~~~~~~~~~~~
-// CHECK:STDERR: fail_mix_extern_decl.carbon:[[@LINE-5]]:1(InImport): in import
-// CHECK:STDERR: fns.carbon:7:1: note(RedeclPrevDecl): previously declared here
+// CHECK:STDERR: fail_mix_extern_decl.carbon:[[@LINE-5]]:1: in import [InImport]
+// CHECK:STDERR: fns.carbon:7:1: note: previously declared here [RedeclPrevDecl]
 // CHECK:STDERR: fn D();
 // CHECK:STDERR: ^~~~~~~
 extern fn D();
@@ -48,7 +48,7 @@ package Test library "[[@TEST_NAME]]";

 import library "def";

-// CHECK:STDERR: fail_local_def.carbon:[[@LINE+4]]:13: error(NameNotFound): name `Def` not found
+// CHECK:STDERR: fail_local_def.carbon:[[@LINE+4]]:13: error: name `Def` not found [NameNotFound]
 // CHECK:STDERR: var f: () = Def();
 // CHECK:STDERR:             ^~~
 // CHECK:STDERR:
@@ -60,7 +60,7 @@ package Other library "[[@TEST_NAME]]";

 import Test library "def";

-// CHECK:STDERR: fail_other_def.carbon:[[@LINE+4]]:13: error(NameNotFound): name `Def` not found
+// CHECK:STDERR: fail_other_def.carbon:[[@LINE+4]]:13: error: name `Def` not found [NameNotFound]
 // CHECK:STDERR: var f: () = Test.Def();
 // CHECK:STDERR:             ^~~~~~~~
 // CHECK:STDERR:
@@ -78,7 +78,7 @@ package Test library "[[@TEST_NAME]]";

 import library "forward_with_def";

-// CHECK:STDERR: fail_local_forward_with_def.carbon:[[@LINE+4]]:13: error(NameNotFound): name `ForwardWithDef` not found
+// CHECK:STDERR: fail_local_forward_with_def.carbon:[[@LINE+4]]:13: error: name `ForwardWithDef` not found [NameNotFound]
 // CHECK:STDERR: var f: () = ForwardWithDef();
 // CHECK:STDERR:             ^~~~~~~~~~~~~~
 // CHECK:STDERR:
@@ -90,7 +90,7 @@ package Other library "[[@TEST_NAME]]";

 import Test library "forward_with_def";

-// CHECK:STDERR: fail_other_forward_with_def.carbon:[[@LINE+4]]:13: error(NameNotFound): name `ForwardWithDef` not found
+// CHECK:STDERR: fail_other_forward_with_def.carbon:[[@LINE+4]]:13: error: name `ForwardWithDef` not found [NameNotFound]
 // CHECK:STDERR: var f: () = Test.ForwardWithDef();
 // CHECK:STDERR:             ^~~~~~~~~~~~~~~~~~~
 // CHECK:STDERR:
@@ -110,7 +110,7 @@ package Test library "[[@TEST_NAME]]";

 import library "forward";

-// CHECK:STDERR: fail_local_forward.carbon:[[@LINE+4]]:13: error(NameNotFound): name `Forward` not found
+// CHECK:STDERR: fail_local_forward.carbon:[[@LINE+4]]:13: error: name `Forward` not found [NameNotFound]
 // CHECK:STDERR: var f: () = Forward();
 // CHECK:STDERR:             ^~~~~~~
 // CHECK:STDERR:
@@ -122,7 +122,7 @@ package Other library "[[@TEST_NAME]]";

 import Test library "forward";

-// CHECK:STDERR: fail_other_forward.carbon:[[@LINE+3]]:13: error(NameNotFound): name `Forward` not found
+// CHECK:STDERR: fail_other_forward.carbon:[[@LINE+3]]:13: error: name `Forward` not found [NameNotFound]
 // CHECK:STDERR: var f: () = Test.Forward();
 // CHECK:STDERR:             ^~~~~~~~~~~~
 var f: () = Test.Forward();
@@ -38,10 +38,10 @@ extern fn F() {}
 library "[[@TEST_NAME]]";

 extern fn F();
-// CHECK:STDERR: fail_def_extern_mismatch.carbon:[[@LINE+7]]:1: error(RedeclExternMismatch): redeclarations of `fn F` must match use of `extern`
+// CHECK:STDERR: fail_def_extern_mismatch.carbon:[[@LINE+7]]:1: error: redeclarations of `fn F` must match use of `extern` [RedeclExternMismatch]
 // CHECK:STDERR: fn F() {}
 // CHECK:STDERR: ^~~~~~~~
-// CHECK:STDERR: fail_def_extern_mismatch.carbon:[[@LINE-4]]:1: note(RedeclPrevDecl): previously declared here
+// CHECK:STDERR: fail_def_extern_mismatch.carbon:[[@LINE-4]]:1: note: previously declared here [RedeclPrevDecl]
 // CHECK:STDERR: extern fn F();
 // CHECK:STDERR: ^~~~~~~~~~~~~~
 // CHECK:STDERR:
@@ -52,10 +52,10 @@ fn F() {}
 library "[[@TEST_NAME]]";

 fn F();
-// CHECK:STDERR: fail_def_extern_mismatch_reverse.carbon:[[@LINE+7]]:1: error(RedeclExternMismatch): redeclarations of `fn F` must match use of `extern`
+// CHECK:STDERR: fail_def_extern_mismatch_reverse.carbon:[[@LINE+7]]:1: error: redeclarations of `fn F` must match use of `extern` [RedeclExternMismatch]
 // CHECK:STDERR: extern fn F() {}
 // CHECK:STDERR: ^~~~~~~~~~~~~~~
-// CHECK:STDERR: fail_def_extern_mismatch_reverse.carbon:[[@LINE-4]]:1: note(RedeclPrevDecl): previously declared here
+// CHECK:STDERR: fail_def_extern_mismatch_reverse.carbon:[[@LINE-4]]:1: note: previously declared here [RedeclPrevDecl]
 // CHECK:STDERR: fn F();
 // CHECK:STDERR: ^~~~~~~
 // CHECK:STDERR:
@@ -66,18 +66,18 @@ extern fn F() {}
 library "[[@TEST_NAME]]";

 extern fn F();
-// CHECK:STDERR: fail_extern_diag_suppressed.carbon:[[@LINE+7]]:1: error(RedeclRedundant): redeclaration of `fn F` is redundant
+// CHECK:STDERR: fail_extern_diag_suppressed.carbon:[[@LINE+7]]:1: error: redeclaration of `fn F` is redundant [RedeclRedundant]
 // CHECK:STDERR: fn F();
 // CHECK:STDERR: ^~~~~~~
-// CHECK:STDERR: fail_extern_diag_suppressed.carbon:[[@LINE-4]]:1: note(RedeclPrevDecl): previously declared here
+// CHECK:STDERR: fail_extern_diag_suppressed.carbon:[[@LINE-4]]:1: note: previously declared here [RedeclPrevDecl]
 // CHECK:STDERR: extern fn F();
 // CHECK:STDERR: ^~~~~~~~~~~~~~
 // CHECK:STDERR:
 fn F();
-// CHECK:STDERR: fail_extern_diag_suppressed.carbon:[[@LINE+7]]:1: error(RedeclExternMismatch): redeclarations of `fn F` must match use of `extern`
+// CHECK:STDERR: fail_extern_diag_suppressed.carbon:[[@LINE+7]]:1: error: redeclarations of `fn F` must match use of `extern` [RedeclExternMismatch]
 // CHECK:STDERR: fn F() {}
 // CHECK:STDERR: ^~~~~~~~
-// CHECK:STDERR: fail_extern_diag_suppressed.carbon:[[@LINE-12]]:1: note(RedeclPrevDecl): previously declared here
+// CHECK:STDERR: fail_extern_diag_suppressed.carbon:[[@LINE-12]]:1: note: previously declared here [RedeclPrevDecl]
 // CHECK:STDERR: extern fn F();
 // CHECK:STDERR: ^~~~~~~~~~~~~~
 // CHECK:STDERR:
@@ -88,10 +88,10 @@ fn F() {}
 library "[[@TEST_NAME]]";

 fn F() {}
-// CHECK:STDERR: fail_extern_decl_after_def.carbon:[[@LINE+7]]:1: error(RedeclRedundant): redeclaration of `fn F` is redundant
+// CHECK:STDERR: fail_extern_decl_after_def.carbon:[[@LINE+7]]:1: error: redeclaration of `fn F` is redundant [RedeclRedundant]
 // CHECK:STDERR: extern fn F();
 // CHECK:STDERR: ^~~~~~~~~~~~~~
-// CHECK:STDERR: fail_extern_decl_after_def.carbon:[[@LINE-4]]:1: note(RedeclPrevDecl): previously declared here
+// CHECK:STDERR: fail_extern_decl_after_def.carbon:[[@LINE-4]]:1: note: previously declared here [RedeclPrevDecl]
 // CHECK:STDERR: fn F() {}
 // CHECK:STDERR: ^~~~~~~~
 // CHECK:STDERR:
@@ -105,7 +105,7 @@ library "[[@TEST_NAME]]";

 impl library "[[@TEST_NAME]]";

-// CHECK:STDERR: fail_in_impl.impl.carbon:[[@LINE+3]]:1: error(ExternRequiresDeclInApiFile): `extern` entities must have a declaration in the API file
+// CHECK:STDERR: fail_in_impl.impl.carbon:[[@LINE+3]]:1: error: `extern` entities must have a declaration in the API file [ExternRequiresDeclInApiFile]
 // CHECK:STDERR: extern fn F() {}
 // CHECK:STDERR: ^~~~~~~~~~~~~~~
 extern fn F() {}
@@ -54,11 +54,11 @@ extern fn F();

 impl library "[[@TEST_NAME]]";

-// CHECK:STDERR: fail_two_file_impl_mismatch.impl.carbon:[[@LINE+8]]:1: error(RedeclExternMismatch): redeclarations of `fn F` must match use of `extern`
+// CHECK:STDERR: fail_two_file_impl_mismatch.impl.carbon:[[@LINE+8]]:1: error: redeclarations of `fn F` must match use of `extern` [RedeclExternMismatch]
 // CHECK:STDERR: fn F() {}
 // CHECK:STDERR: ^~~~~~~~
-// CHECK:STDERR: fail_two_file_impl_mismatch.impl.carbon:[[@LINE-5]]:6(InImport): in import
-// CHECK:STDERR: two_file_impl_mismatch.carbon:4:1: note(RedeclPrevDecl): previously declared here
+// CHECK:STDERR: fail_two_file_impl_mismatch.impl.carbon:[[@LINE-5]]:6: in import [InImport]
+// CHECK:STDERR: two_file_impl_mismatch.carbon:4:1: note: previously declared here [RedeclPrevDecl]
 // CHECK:STDERR: extern fn F();
 // CHECK:STDERR: ^~~~~~~~~~~~~~
 // CHECK:STDERR:
@@ -80,7 +80,7 @@ import library "indirect_two_file_extern";

 impl library "[[@TEST_NAME]]";

-// CHECK:STDERR: fail_indirect_two_file.impl.carbon:[[@LINE+4]]:1: error(ExternRequiresDeclInApiFile): `extern` entities must have a declaration in the API file
+// CHECK:STDERR: fail_indirect_two_file.impl.carbon:[[@LINE+4]]:1: error: `extern` entities must have a declaration in the API file [ExternRequiresDeclInApiFile]
 // CHECK:STDERR: extern fn F() {}
 // CHECK:STDERR: ^~~~~~~~~~~~~~~
 // CHECK:STDERR:
@@ -102,7 +102,7 @@ impl library "[[@TEST_NAME]]";

 import library "in_impl_extern";

-// CHECK:STDERR: fail_in_impl.impl.carbon:[[@LINE+3]]:1: error(ExternRequiresDeclInApiFile): `extern` entities must have a declaration in the API file
+// CHECK:STDERR: fail_in_impl.impl.carbon:[[@LINE+3]]:1: error: `extern` entities must have a declaration in the API file [ExternRequiresDeclInApiFile]
 // CHECK:STDERR: extern fn F() {}
 // CHECK:STDERR: ^~~~~~~~~~~~~~~
 extern fn F() {}
@@ -9,57 +9,57 @@
 // TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/function/definition/no_prelude/fail_decl_param_mismatch.carbon

 fn F();
-// CHECK:STDERR: fail_decl_param_mismatch.carbon:[[@LINE+7]]:1: error(RedeclParamCountDiffers): redeclaration differs because of parameter count of 1
+// CHECK:STDERR: fail_decl_param_mismatch.carbon:[[@LINE+7]]:1: error: redeclaration differs because of parameter count of 1 [RedeclParamCountDiffers]
 // CHECK:STDERR: fn F(x: ()) {}
 // CHECK:STDERR: ^~~~~~~~~~~~~
-// CHECK:STDERR: fail_decl_param_mismatch.carbon:[[@LINE-4]]:1: note(RedeclParamCountPrevious): previously declared with parameter count of 0
+// CHECK:STDERR: fail_decl_param_mismatch.carbon:[[@LINE-4]]:1: note: previously declared with parameter count of 0 [RedeclParamCountPrevious]
 // CHECK:STDERR: fn F();
 // CHECK:STDERR: ^~~~~~~
 // CHECK:STDERR:
 fn F(x: ()) {}

 fn G(x: ());
-// CHECK:STDERR: fail_decl_param_mismatch.carbon:[[@LINE+7]]:1: error(RedeclParamCountDiffers): redeclaration differs because of parameter count of 0
+// CHECK:STDERR: fail_decl_param_mismatch.carbon:[[@LINE+7]]:1: error: redeclaration differs because of parameter count of 0 [RedeclParamCountDiffers]
 // CHECK:STDERR: fn G() {}
 // CHECK:STDERR: ^~~~~~~~
-// CHECK:STDERR: fail_decl_param_mismatch.carbon:[[@LINE-4]]:1: note(RedeclParamCountPrevious): previously declared with parameter count of 1
+// CHECK:STDERR: fail_decl_param_mismatch.carbon:[[@LINE-4]]:1: note: previously declared with parameter count of 1 [RedeclParamCountPrevious]
 // CHECK:STDERR: fn G(x: ());
 // CHECK:STDERR: ^~~~~~~~~~~~
 // CHECK:STDERR:
 fn G() {}

 fn H(x: ());
-// CHECK:STDERR: fail_decl_param_mismatch.carbon:[[@LINE+4]]:9: error(CoreNotFound): package `Core` implicitly referenced here, but not found
+// CHECK:STDERR: fail_decl_param_mismatch.carbon:[[@LINE+4]]:9: error: package `Core` implicitly referenced here, but not found [CoreNotFound]
 // CHECK:STDERR: fn H(x: bool) {}
 // CHECK:STDERR:         ^~~~
 // CHECK:STDERR:
 fn H(x: bool) {}

 fn I();
-// CHECK:STDERR: fail_decl_param_mismatch.carbon:[[@LINE+7]]:1: error(FunctionRedeclReturnTypeDiffers): function redeclaration differs because return type is `()`
+// CHECK:STDERR: fail_decl_param_mismatch.carbon:[[@LINE+7]]:1: error: function redeclaration differs because return type is `()` [FunctionRedeclReturnTypeDiffers]
 // CHECK:STDERR: fn I() -> () { return (); }
 // CHECK:STDERR: ^~~~~~~~~~~~~~
-// CHECK:STDERR: fail_decl_param_mismatch.carbon:[[@LINE-4]]:1: note(FunctionRedeclReturnTypePreviousNoReturn): previously declared with no return type
+// CHECK:STDERR: fail_decl_param_mismatch.carbon:[[@LINE-4]]:1: note: previously declared with no return type [FunctionRedeclReturnTypePreviousNoReturn]
 // CHECK:STDERR: fn I();
 // CHECK:STDERR: ^~~~~~~
 // CHECK:STDERR:
 fn I() -> () { return (); }

 fn J() -> ();
-// CHECK:STDERR: fail_decl_param_mismatch.carbon:[[@LINE+7]]:1: error(FunctionRedeclReturnTypeDiffersNoReturn): function redeclaration differs because no return type is provided
+// CHECK:STDERR: fail_decl_param_mismatch.carbon:[[@LINE+7]]:1: error: function redeclaration differs because no return type is provided [FunctionRedeclReturnTypeDiffersNoReturn]
 // CHECK:STDERR: fn J() {}
 // CHECK:STDERR: ^~~~~~~~
-// CHECK:STDERR: fail_decl_param_mismatch.carbon:[[@LINE-4]]:1: note(FunctionRedeclReturnTypePrevious): previously declared with return type `()`
+// CHECK:STDERR: fail_decl_param_mismatch.carbon:[[@LINE-4]]:1: note: previously declared with return type `()` [FunctionRedeclReturnTypePrevious]
 // CHECK:STDERR: fn J() -> ();
 // CHECK:STDERR: ^~~~~~~~~~~~~
 // CHECK:STDERR:
 fn J() {}

 fn K() -> ();
-// CHECK:STDERR: fail_decl_param_mismatch.carbon:[[@LINE+6]]:1: error(FunctionRedeclReturnTypeDiffers): function redeclaration differs because return type is `{}`
+// CHECK:STDERR: fail_decl_param_mismatch.carbon:[[@LINE+6]]:1: error: function redeclaration differs because return type is `{}` [FunctionRedeclReturnTypeDiffers]
 // CHECK:STDERR: fn K() -> {} { return {}; }
 // CHECK:STDERR: ^~~~~~~~~~~~~~
-// CHECK:STDERR: fail_decl_param_mismatch.carbon:[[@LINE-4]]:1: note(FunctionRedeclReturnTypePrevious): previously declared with return type `()`
+// CHECK:STDERR: fail_decl_param_mismatch.carbon:[[@LINE-4]]:1: note: previously declared with return type `()` [FunctionRedeclReturnTypePrevious]
 // CHECK:STDERR: fn K() -> ();
 // CHECK:STDERR: ^~~~~~~~~~~~~
 fn K() -> {} { return {}; }
@@ -9,10 +9,10 @@
 // TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/function/definition/no_prelude/fail_redef.carbon

 fn F() {}
-// CHECK:STDERR: fail_redef.carbon:[[@LINE+6]]:1: error(RedeclRedef): redefinition of `fn F`
+// CHECK:STDERR: fail_redef.carbon:[[@LINE+6]]:1: error: redefinition of `fn F` [RedeclRedef]
 // CHECK:STDERR: fn F() {}
 // CHECK:STDERR: ^~~~~~~~
-// CHECK:STDERR: fail_redef.carbon:[[@LINE-4]]:1: note(RedeclPrevDef): previously defined here
+// CHECK:STDERR: fail_redef.carbon:[[@LINE-4]]:1: note: previously defined here [RedeclPrevDef]
 // CHECK:STDERR: fn F() {}
 // CHECK:STDERR: ^~~~~~~~
 fn F() {}
@@ -30,11 +30,11 @@ extern fn A();

 impl library "[[@TEST_NAME]]";

-// CHECK:STDERR: fail_extern_api.impl.carbon:[[@LINE+8]]:1: error(RedeclExternMismatch): redeclarations of `fn A` must match use of `extern`
+// CHECK:STDERR: fail_extern_api.impl.carbon:[[@LINE+8]]:1: error: redeclarations of `fn A` must match use of `extern` [RedeclExternMismatch]
 // CHECK:STDERR: fn A() {}
 // CHECK:STDERR: ^~~~~~~~
-// CHECK:STDERR: fail_extern_api.impl.carbon:[[@LINE-5]]:6(InImport): in import
-// CHECK:STDERR: extern_api.carbon:4:1: note(RedeclPrevDecl): previously declared here
+// CHECK:STDERR: fail_extern_api.impl.carbon:[[@LINE-5]]:6: in import [InImport]
+// CHECK:STDERR: extern_api.carbon:4:1: note: previously declared here [RedeclPrevDecl]
 // CHECK:STDERR: extern fn A();
 // CHECK:STDERR: ^~~~~~~~~~~~~~
 // CHECK:STDERR:
@@ -50,11 +50,11 @@ fn A();

 impl library "[[@TEST_NAME]]";

-// CHECK:STDERR: fail_extern_impl.impl.carbon:[[@LINE+8]]:1: error(RedeclExternMismatch): redeclarations of `fn A` must match use of `extern`
+// CHECK:STDERR: fail_extern_impl.impl.carbon:[[@LINE+8]]:1: error: redeclarations of `fn A` must match use of `extern` [RedeclExternMismatch]
 // CHECK:STDERR: extern fn A() {}
 // CHECK:STDERR: ^~~~~~~~~~~~~~~
-// CHECK:STDERR: fail_extern_impl.impl.carbon:[[@LINE-5]]:6(InImport): in import
-// CHECK:STDERR: extern_impl.carbon:4:1: note(RedeclPrevDecl): previously declared here
+// CHECK:STDERR: fail_extern_impl.impl.carbon:[[@LINE-5]]:6: in import [InImport]
+// CHECK:STDERR: extern_impl.carbon:4:1: note: previously declared here [RedeclPrevDecl]
 // CHECK:STDERR: fn A();
 // CHECK:STDERR: ^~~~~~~
 // CHECK:STDERR:
@@ -70,11 +70,11 @@ fn A() {}

 impl library "[[@TEST_NAME]]";

-// CHECK:STDERR: fail_redecl_after_def.impl.carbon:[[@LINE+8]]:1: error(RedeclRedundant): redeclaration of `fn A` is redundant
+// CHECK:STDERR: fail_redecl_after_def.impl.carbon:[[@LINE+8]]:1: error: redeclaration of `fn A` is redundant [RedeclRedundant]
 // CHECK:STDERR: fn A();
 // CHECK:STDERR: ^~~~~~~
-// CHECK:STDERR: fail_redecl_after_def.impl.carbon:[[@LINE-5]]:6(InImport): in import
-// CHECK:STDERR: redecl_after_def.carbon:4:1: note(RedeclPrevDecl): previously declared here
+// CHECK:STDERR: fail_redecl_after_def.impl.carbon:[[@LINE-5]]:6: in import [InImport]
+// CHECK:STDERR: redecl_after_def.carbon:4:1: note: previously declared here [RedeclPrevDecl]
 // CHECK:STDERR: fn A() {}
 // CHECK:STDERR: ^~~~~~~~
 // CHECK:STDERR:
@@ -90,11 +90,11 @@ fn A() {}

 impl library "[[@TEST_NAME]]";

-// CHECK:STDERR: fail_redef_after_def.impl.carbon:[[@LINE+8]]:1: error(RedeclRedef): redefinition of `fn A`
+// CHECK:STDERR: fail_redef_after_def.impl.carbon:[[@LINE+8]]:1: error: redefinition of `fn A` [RedeclRedef]
 // CHECK:STDERR: fn A() {}
 // CHECK:STDERR: ^~~~~~~~
-// CHECK:STDERR: fail_redef_after_def.impl.carbon:[[@LINE-5]]:6(InImport): in import
-// CHECK:STDERR: redef_after_def.carbon:4:1: note(RedeclPrevDef): previously defined here
+// CHECK:STDERR: fail_redef_after_def.impl.carbon:[[@LINE-5]]:6: in import [InImport]
+// CHECK:STDERR: redef_after_def.carbon:4:1: note: previously defined here [RedeclPrevDef]
 // CHECK:STDERR: fn A() {}
 // CHECK:STDERR: ^~~~~~~~
 // CHECK:STDERR:
@@ -111,11 +111,11 @@ alias B = A;

 impl library "[[@TEST_NAME]]";

-// CHECK:STDERR: fail_def_alias.impl.carbon:[[@LINE+7]]:1: error(NameDeclDuplicate): duplicate name being declared in the same scope
+// CHECK:STDERR: fail_def_alias.impl.carbon:[[@LINE+7]]:1: error: duplicate name being declared in the same scope [NameDeclDuplicate]
 // CHECK:STDERR: fn B() {}
 // CHECK:STDERR: ^~~~~~~~
-// CHECK:STDERR: fail_def_alias.impl.carbon:[[@LINE-5]]:6(InImport): in import
-// CHECK:STDERR: def_alias.carbon:5:7: note(NameDeclPrevious): name is previously declared here
+// CHECK:STDERR: fail_def_alias.impl.carbon:[[@LINE-5]]:6: in import [InImport]
+// CHECK:STDERR: def_alias.carbon:5:7: note: name is previously declared here [NameDeclPrevious]
 // CHECK:STDERR: alias B = A;
 // CHECK:STDERR:       ^
 fn B() {}
@@ -37,10 +37,10 @@ library "[[@TEST_NAME]]";
 class C {}

 fn Foo(a: C);
-// CHECK:STDERR: fail_parens.carbon:[[@LINE+7]]:11: error(RedeclParamSyntaxDiffers): redeclaration syntax differs here
+// CHECK:STDERR: fail_parens.carbon:[[@LINE+7]]:11: error: redeclaration syntax differs here [RedeclParamSyntaxDiffers]
 // CHECK:STDERR: fn Foo(a: (C)) {}
 // CHECK:STDERR:           ^
-// CHECK:STDERR: fail_parens.carbon:[[@LINE-4]]:11: note(RedeclParamSyntaxPrevious): comparing with previous declaration here
+// CHECK:STDERR: fail_parens.carbon:[[@LINE-4]]:11: note: comparing with previous declaration here [RedeclParamSyntaxPrevious]
 // CHECK:STDERR: fn Foo(a: C);
 // CHECK:STDERR:           ^
 // CHECK:STDERR:
@@ -80,10 +80,10 @@ class C {}
 alias D = C;

 fn Foo(a: C);
-// CHECK:STDERR: fail_name_mismatch.carbon:[[@LINE+7]]:8: error(RedeclParamDiffers): redeclaration differs at parameter 1
+// CHECK:STDERR: fail_name_mismatch.carbon:[[@LINE+7]]:8: error: redeclaration differs at parameter 1 [RedeclParamDiffers]
 // CHECK:STDERR: fn Foo(b: D) {}
 // CHECK:STDERR:        ^~~~
-// CHECK:STDERR: fail_name_mismatch.carbon:[[@LINE-4]]:8: note(RedeclParamPrevious): previous declaration's corresponding parameter here
+// CHECK:STDERR: fail_name_mismatch.carbon:[[@LINE-4]]:8: note: previous declaration's corresponding parameter here [RedeclParamPrevious]
 // CHECK:STDERR: fn Foo(a: C);
 // CHECK:STDERR:        ^~~~
 // CHECK:STDERR:
@@ -97,10 +97,10 @@ class C {}
 alias D = C;

 fn Foo(a: C);
-// CHECK:STDERR: fail_alias.carbon:[[@LINE+7]]:11: error(RedeclParamSyntaxDiffers): redeclaration syntax differs here
+// CHECK:STDERR: fail_alias.carbon:[[@LINE+7]]:11: error: redeclaration syntax differs here [RedeclParamSyntaxDiffers]
 // CHECK:STDERR: fn Foo(a: D) {}
 // CHECK:STDERR:           ^
-// CHECK:STDERR: fail_alias.carbon:[[@LINE-4]]:11: note(RedeclParamSyntaxPrevious): comparing with previous declaration here
+// CHECK:STDERR: fail_alias.carbon:[[@LINE-4]]:11: note: comparing with previous declaration here [RedeclParamSyntaxPrevious]
 // CHECK:STDERR: fn Foo(a: C);
 // CHECK:STDERR:           ^
 // CHECK:STDERR:
@@ -114,10 +114,10 @@ class C {}
 alias D = C;

 fn Foo[a:! C]();
-// CHECK:STDERR: fail_deduced_alias.carbon:[[@LINE+7]]:12: error(RedeclParamSyntaxDiffers): redeclaration syntax differs here
+// CHECK:STDERR: fail_deduced_alias.carbon:[[@LINE+7]]:12: error: redeclaration syntax differs here [RedeclParamSyntaxDiffers]
 // CHECK:STDERR: fn Foo[a:! D]() {}
 // CHECK:STDERR:            ^
-// CHECK:STDERR: fail_deduced_alias.carbon:[[@LINE-4]]:12: note(RedeclParamSyntaxPrevious): comparing with previous declaration here
+// CHECK:STDERR: fail_deduced_alias.carbon:[[@LINE-4]]:12: note: comparing with previous declaration here [RedeclParamSyntaxPrevious]
 // CHECK:STDERR: fn Foo[a:! C]();
 // CHECK:STDERR:            ^
 // CHECK:STDERR:
@@ -156,14 +156,14 @@ library "[[@TEST_NAME]]";
 class C {}

 fn Foo(a: const C);
-// CHECK:STDERR: fail_repeat_const.carbon:[[@LINE+10]]:11: warning(RepeatedConst): `const` applied repeatedly to the same type has no additional effect
+// CHECK:STDERR: fail_repeat_const.carbon:[[@LINE+10]]:11: warning: `const` applied repeatedly to the same type has no additional effect [RepeatedConst]
 // CHECK:STDERR: fn Foo(a: const (const C)) {}
 // CHECK:STDERR:           ^~~~~~~~~~~~~~~
 // CHECK:STDERR:
-// CHECK:STDERR: fail_repeat_const.carbon:[[@LINE+6]]:17: error(RedeclParamSyntaxDiffers): redeclaration syntax differs here
+// CHECK:STDERR: fail_repeat_const.carbon:[[@LINE+6]]:17: error: redeclaration syntax differs here [RedeclParamSyntaxDiffers]
 // CHECK:STDERR: fn Foo(a: const (const C)) {}
 // CHECK:STDERR:                 ^
-// CHECK:STDERR: fail_repeat_const.carbon:[[@LINE-8]]:17: note(RedeclParamSyntaxPrevious): comparing with previous declaration here
+// CHECK:STDERR: fail_repeat_const.carbon:[[@LINE-8]]:17: note: comparing with previous declaration here [RedeclParamSyntaxPrevious]
 // CHECK:STDERR: fn Foo(a: const C);
 // CHECK:STDERR:                 ^
 fn Foo(a: const (const C)) {}
@@ -33,10 +33,10 @@ fn CallExplicitGenericParamConst(T:! type) {
 }

 fn CallExplicitGenericParamNonConst(T: type) {
-  // CHECK:STDERR: fail_deduce_explicit_non_constant.carbon:[[@LINE+7]]:3: error(CompTimeArgumentNotConstant): argument for generic parameter is not a compile-time constant
+  // CHECK:STDERR: fail_deduce_explicit_non_constant.carbon:[[@LINE+7]]:3: error: argument for generic parameter is not a compile-time constant [CompTimeArgumentNotConstant]
  // CHECK:STDERR:   ExplicitGenericParam(T);
  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~~~~~
-  // CHECK:STDERR: fail_deduce_explicit_non_constant.carbon:[[@LINE-10]]:25: note(InitializingGenericParam): initializing generic parameter `T` declared here
+  // CHECK:STDERR: fail_deduce_explicit_non_constant.carbon:[[@LINE-10]]:25: note: initializing generic parameter `T` declared here [InitializingGenericParam]
  // CHECK:STDERR: fn ExplicitGenericParam(T:! type) -> T* { return ExplicitGenericParam(T); }
  // CHECK:STDERR:                         ^
  // CHECK:STDERR:
@@ -84,10 +84,10 @@ library "[[@TEST_NAME]]";
 fn StructParam[T:! type](x: {.a: T, .b: i32}) {}

 fn CallStructParam() {
-  // CHECK:STDERR: fail_todo_deduce_nested_struct.carbon:[[@LINE+7]]:3: error(DeductionIncomplete): cannot deduce value for generic parameter `T`
+  // CHECK:STDERR: fail_todo_deduce_nested_struct.carbon:[[@LINE+7]]:3: error: cannot deduce value for generic parameter `T` [DeductionIncomplete]
  // CHECK:STDERR:   StructParam({.a = 1, .b = 2});
  // CHECK:STDERR:   ^~~~~~~~~~~~
-  // CHECK:STDERR: fail_todo_deduce_nested_struct.carbon:[[@LINE-6]]:1: note(DeductionGenericHere): while deducing parameters of generic declared here
+  // CHECK:STDERR: fail_todo_deduce_nested_struct.carbon:[[@LINE-6]]:1: note: while deducing parameters of generic declared here [DeductionGenericHere]
  // CHECK:STDERR: fn StructParam[T:! type](x: {.a: T, .b: i32}) {}
  // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  // CHECK:STDERR:
@@ -103,10 +103,10 @@ library "[[@TEST_NAME]]";
 fn ImplicitNotDeducible[T:! type, U:! type](x: T) -> U;

 fn CallImplicitNotDeducible() {
-  // CHECK:STDERR: fail_deduce_incomplete.carbon:[[@LINE+7]]:3: error(DeductionIncomplete): cannot deduce value for generic parameter `U`
+  // CHECK:STDERR: fail_deduce_incomplete.carbon:[[@LINE+7]]:3: error: cannot deduce value for generic parameter `U` [DeductionIncomplete]
  // CHECK:STDERR:   ImplicitNotDeducible(42);
  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~~~~~
-  // CHECK:STDERR: fail_deduce_incomplete.carbon:[[@LINE-6]]:1: note(DeductionGenericHere): while deducing parameters of generic declared here
+  // CHECK:STDERR: fail_deduce_incomplete.carbon:[[@LINE-6]]:1: note: while deducing parameters of generic declared here [DeductionGenericHere]
  // CHECK:STDERR: fn ImplicitNotDeducible[T:! type, U:! type](x: T) -> U;
  // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  // CHECK:STDERR:
@@ -120,10 +120,10 @@ library "[[@TEST_NAME]]";
 fn ImplicitNotDeducible[T:! type](x: T, y: T) -> T;

 fn CallImplicitNotDeducible() {
-  // CHECK:STDERR: fail_deduce_inconsistent.carbon:[[@LINE+6]]:3: error(DeductionInconsistent): inconsistent deductions for value of generic parameter `T`
+  // CHECK:STDERR: fail_deduce_inconsistent.carbon:[[@LINE+6]]:3: error: inconsistent deductions for value of generic parameter `T` [DeductionInconsistent]
  // CHECK:STDERR:   ImplicitNotDeducible(42, {.x = 12});
  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~~~~~
-  // CHECK:STDERR: fail_deduce_inconsistent.carbon:[[@LINE-6]]:1: note(DeductionGenericHere): while deducing parameters of generic declared here
+  // CHECK:STDERR: fail_deduce_inconsistent.carbon:[[@LINE-6]]:1: note: while deducing parameters of generic declared here [DeductionGenericHere]
  // CHECK:STDERR: fn ImplicitNotDeducible[T:! type](x: T, y: T) -> T;
  // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  ImplicitNotDeducible(42, {.x = 12});
@@ -8,7 +8,7 @@
 // TIP: To dump output, run:
 // TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/function/generic/fail_todo_param_in_type.carbon

-// CHECK:STDERR: fail_todo_param_in_type.carbon:[[@LINE+3]]:24: error(SemanticsTodo): semantics TODO: `symbolic array bound`
+// CHECK:STDERR: fail_todo_param_in_type.carbon:[[@LINE+3]]:24: error: semantics TODO: `symbolic array bound` [SemanticsTodo]
 // CHECK:STDERR: fn F(N:! i32, a: [i32; N]*);
 // CHECK:STDERR:                        ^
 fn F(N:! i32, a: [i32; N]*);
@@ -10,7 +10,7 @@

 fn F(T:! type, U:! type) {
  var p: T*;
-  // CHECK:STDERR: fail_type_param_mismatch.carbon:[[@LINE+3]]:3: error(CoreNotFound): package `Core` implicitly referenced here, but not found
+  // CHECK:STDERR: fail_type_param_mismatch.carbon:[[@LINE+3]]:3: error: package `Core` implicitly referenced here, but not found [CoreNotFound]
  // CHECK:STDERR:   let n: U = *p;
  // CHECK:STDERR:   ^~~~~~~~~~~~~~
  let n: U = *p;
@@ -24,18 +24,18 @@ library "[[@TEST_NAME]]";

 fn F(T:! type, U:! type) -> T*;

-// CHECK:STDERR: fail_different_return_type.carbon:[[@LINE+7]]:1: error(FunctionRedeclReturnTypeDiffers): function redeclaration differs because return type is `U*`
+// CHECK:STDERR: fail_different_return_type.carbon:[[@LINE+7]]:1: error: function redeclaration differs because return type is `U*` [FunctionRedeclReturnTypeDiffers]
 // CHECK:STDERR: fn F(T:! type, U:! type) -> U* {
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-// CHECK:STDERR: fail_different_return_type.carbon:[[@LINE-5]]:1: note(FunctionRedeclReturnTypePrevious): previously declared with return type `T*`
+// CHECK:STDERR: fail_different_return_type.carbon:[[@LINE-5]]:1: note: previously declared with return type `T*` [FunctionRedeclReturnTypePrevious]
 // CHECK:STDERR: fn F(T:! type, U:! type) -> T*;
 // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 // CHECK:STDERR:
 fn F(T:! type, U:! type) -> U* {
-  // CHECK:STDERR: fail_different_return_type.carbon:[[@LINE+7]]:10: error(CallArgCountMismatch): 1 argument passed to function expecting 2 arguments
+  // CHECK:STDERR: fail_different_return_type.carbon:[[@LINE+7]]:10: error: 1 argument passed to function expecting 2 arguments [CallArgCountMismatch]
  // CHECK:STDERR:   return F(T);
  // CHECK:STDERR:          ^~
-  // CHECK:STDERR: fail_different_return_type.carbon:[[@LINE-13]]:1: note(InCallToEntity): calling function declared here
+  // CHECK:STDERR: fail_different_return_type.carbon:[[@LINE-13]]:1: note: calling function declared here [InCallToEntity]
  // CHECK:STDERR: fn F(T:! type, U:! type) -> T*;
  // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  // CHECK:STDERR:
@@ -48,18 +48,18 @@ library "[[@TEST_NAME]]";

 fn F(T:! type, U:! type) -> T*;

-// CHECK:STDERR: fail_reorder.carbon:[[@LINE+7]]:6: error(RedeclParamDiffers): redeclaration differs at parameter 1
+// CHECK:STDERR: fail_reorder.carbon:[[@LINE+7]]:6: error: redeclaration differs at parameter 1 [RedeclParamDiffers]
 // CHECK:STDERR: fn F(U:! type, T:! type) -> T* {
 // CHECK:STDERR:      ^~~~~~~~
-// CHECK:STDERR: fail_reorder.carbon:[[@LINE-5]]:6: note(RedeclParamPrevious): previous declaration's corresponding parameter here
+// CHECK:STDERR: fail_reorder.carbon:[[@LINE-5]]:6: note: previous declaration's corresponding parameter here [RedeclParamPrevious]
 // CHECK:STDERR: fn F(T:! type, U:! type) -> T*;
 // CHECK:STDERR:      ^~~~~~~~
 // CHECK:STDERR:
 fn F(U:! type, T:! type) -> T* {
-  // CHECK:STDERR: fail_reorder.carbon:[[@LINE+7]]:10: error(CallArgCountMismatch): 1 argument passed to function expecting 2 arguments
+  // CHECK:STDERR: fail_reorder.carbon:[[@LINE+7]]:10: error: 1 argument passed to function expecting 2 arguments [CallArgCountMismatch]
  // CHECK:STDERR:   return F(T);
  // CHECK:STDERR:          ^~
-  // CHECK:STDERR: fail_reorder.carbon:[[@LINE-13]]:1: note(InCallToEntity): calling function declared here
+  // CHECK:STDERR: fail_reorder.carbon:[[@LINE-13]]:1: note: calling function declared here [InCallToEntity]
  // CHECK:STDERR: fn F(T:! type, U:! type) -> T*;
  // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  // CHECK:STDERR:
@@ -72,18 +72,18 @@ library "[[@TEST_NAME]]";

 fn F(T:! type, U:! type) -> T*;

-// CHECK:STDERR: fail_rename.carbon:[[@LINE+7]]:6: error(RedeclParamDiffers): redeclaration differs at parameter 1
+// CHECK:STDERR: fail_rename.carbon:[[@LINE+7]]:6: error: redeclaration differs at parameter 1 [RedeclParamDiffers]
 // CHECK:STDERR: fn F(U:! type, T:! type) -> U* {
 // CHECK:STDERR:      ^~~~~~~~
-// CHECK:STDERR: fail_rename.carbon:[[@LINE-5]]:6: note(RedeclParamPrevious): previous declaration's corresponding parameter here
+// CHECK:STDERR: fail_rename.carbon:[[@LINE-5]]:6: note: previous declaration's corresponding parameter here [RedeclParamPrevious]
 // CHECK:STDERR: fn F(T:! type, U:! type) -> T*;
 // CHECK:STDERR:      ^~~~~~~~
 // CHECK:STDERR:
 fn F(U:! type, T:! type) -> U* {
-  // CHECK:STDERR: fail_rename.carbon:[[@LINE+6]]:10: error(CallArgCountMismatch): 1 argument passed to function expecting 2 arguments
+  // CHECK:STDERR: fail_rename.carbon:[[@LINE+6]]:10: error: 1 argument passed to function expecting 2 arguments [CallArgCountMismatch]
  // CHECK:STDERR:   return F(T);
  // CHECK:STDERR:          ^~
-  // CHECK:STDERR: fail_rename.carbon:[[@LINE-13]]:1: note(InCallToEntity): calling function declared here
+  // CHECK:STDERR: fail_rename.carbon:[[@LINE-13]]:1: note: calling function declared here [InCallToEntity]
  // CHECK:STDERR: fn F(T:! type, U:! type) -> T*;
  // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  return F(T);
@@ -17,7 +17,7 @@ fn ErrorIfNIsZero(N:! i32) {
  // ensuring we produce an error when doing so. Notionally this error is
  // produced as a result of instantiating the `Core.Int` template, although
  // that's not how we currently model `Core.Int`.
-  // CHECK:STDERR: fail_call_monomorphization_error.carbon:[[@LINE+3]]:10: error(IntWidthNotPositive): integer type width of 0 is not positive
+  // CHECK:STDERR: fail_call_monomorphization_error.carbon:[[@LINE+3]]:10: error: integer type width of 0 is not positive [IntWidthNotPositive]
  // CHECK:STDERR:   var v: Core.Int(N);
  // CHECK:STDERR:          ^~~~~~~~~
  var v: Core.Int(N);
@@ -41,10 +41,10 @@ library "[[@TEST_NAME]]";
 fn Undefined[T:! type](x: T) -> T;

 fn CallUndefined() -> i32 {
-  // CHECK:STDERR: fail_call_undefined.carbon:[[@LINE+6]]:10: error(MissingGenericFunctionDefinition): use of undefined generic function
+  // CHECK:STDERR: fail_call_undefined.carbon:[[@LINE+6]]:10: error: use of undefined generic function [MissingGenericFunctionDefinition]
  // CHECK:STDERR:   return Undefined(0);
  // CHECK:STDERR:          ^~~~~~~~~
-  // CHECK:STDERR: fail_call_undefined.carbon:[[@LINE-6]]:1: note(MissingGenericFunctionDefinitionHere): generic function declared here
+  // CHECK:STDERR: fail_call_undefined.carbon:[[@LINE-6]]:1: note: generic function declared here [MissingGenericFunctionDefinitionHere]
  // CHECK:STDERR: fn Undefined[T:! type](x: T) -> T;
  // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  return Undefined(0);