// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
// Exceptions. See /LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
// AUTOUPDATE
// TIP: To test this file alone, run:
// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/parse/testdata/function/declaration.carbon
// TIP: To dump output, run:
// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/parse/testdata/function/declaration.carbon

// --- basic.carbon

fn F();

// --- ref.carbon

fn foo(ref a: i32);

// --- implicit_empty.carbon

fn foo[]();

// --- implicit_params.carbon

fn foo[a: i32, b: i32]();

// --- no_params.carbon

fn foo {}

// --- params.carbon

fn foo(a: i32, b: i32);

// --- with_return_type.carbon

fn foo() -> u32;

// --- impl_fn.carbon

override fn F();
abstract override fn G();
override abstract fn H();
private override default fn I();

// --- fail_identifier_instead_of_sig.carbon

// CHECK:STDERR: fail_identifier_instead_of_sig.carbon:[[@LINE+4]]:8: error: `fn` declarations must either end with a `;` or have a `{ ... }` block for a definition [ExpectedDeclSemiOrDefinition]
// CHECK:STDERR: fn foo bar;
// CHECK:STDERR:        ^~~
// CHECK:STDERR:
fn foo bar;

// --- fail_missing_implicit_close.carbon

// CHECK:STDERR: fail_missing_implicit_close.carbon:[[@LINE+8]]:7: error: opening symbol without a corresponding closing symbol [UnmatchedOpening]
// CHECK:STDERR: fn Div[();
// CHECK:STDERR:       ^
// CHECK:STDERR:
// CHECK:STDERR: fail_missing_implicit_close.carbon:[[@LINE+4]]:7: error: `fn` declarations must either end with a `;` or have a `{ ... }` block for a definition [ExpectedDeclSemiOrDefinition]
// CHECK:STDERR: fn Div[();
// CHECK:STDERR:       ^
// CHECK:STDERR:
fn Div[();

// --- fail_missing_name.carbon

// CHECK:STDERR: fail_missing_name.carbon:[[@LINE+4]]:4: error: `fn` introducer should be followed by a name [ExpectedDeclName]
// CHECK:STDERR: fn ();
// CHECK:STDERR:    ^
// CHECK:STDERR:
fn ();

// --- fail_no_sig_or_semi.carbon

fn foo
// CHECK:STDERR: fail_no_sig_or_semi.carbon:[[@LINE+4]]:1: error: `fn` declarations must either end with a `;` or have a `{ ... }` block for a definition [ExpectedDeclSemiOrDefinition]
// CHECK:STDERR:
// CHECK:STDERR: ^
// CHECK:STDERR:

// --- fail_only_fn_and_semi.carbon

// CHECK:STDERR: fail_only_fn_and_semi.carbon:[[@LINE+4]]:3: error: `fn` introducer should be followed by a name [ExpectedDeclName]
// CHECK:STDERR: fn;
// CHECK:STDERR:   ^
// CHECK:STDERR:
fn;

// --- fail_repeated_fn_and_semi.carbon

// CHECK:STDERR: fail_repeated_fn_and_semi.carbon:[[@LINE+4]]:4: error: `fn` introducer should be followed by a name [ExpectedDeclName]
// CHECK:STDERR: fn fn;
// CHECK:STDERR:    ^~
// CHECK:STDERR:
fn fn;

// --- fail_skip_indented_newline_until_outdent.carbon

  // CHECK:STDERR: fail_skip_indented_newline_until_outdent.carbon:[[@LINE+4]]:6: error: `fn` introducer should be followed by a name [ExpectedDeclName]
  // CHECK:STDERR:   fn (x,
  // CHECK:STDERR:      ^
  // CHECK:STDERR:
  fn (x,
      y,
      z)
fn F();

// --- fail_skip_indented_newline_with_semi.carbon

// CHECK:STDERR: fail_skip_indented_newline_with_semi.carbon:[[@LINE+4]]:4: error: `fn` introducer should be followed by a name [ExpectedDeclName]
// CHECK:STDERR: fn (x,
// CHECK:STDERR:    ^
// CHECK:STDERR:
fn (x,
    y,
    z);
fn F();

// --- fail_skip_indented_newline_without_semi.carbon

// CHECK:STDERR: fail_skip_indented_newline_without_semi.carbon:[[@LINE+4]]:4: error: `fn` introducer should be followed by a name [ExpectedDeclName]
// CHECK:STDERR: fn (x,
// CHECK:STDERR:    ^
// CHECK:STDERR:
fn (x,
    y,
    z)
fn F();

// --- fail_skip_to_newline_without_semi.carbon

// CHECK:STDERR: fail_skip_to_newline_without_semi.carbon:[[@LINE+4]]:4: error: `fn` introducer should be followed by a name [ExpectedDeclName]
// CHECK:STDERR: fn ()
// CHECK:STDERR:    ^
// CHECK:STDERR:
fn ()
fn F();

// --- fail_skip_without_semi_to_curly.carbon

// CHECK:STDERR: fail_skip_without_semi_to_curly.carbon:[[@LINE+4]]:1: error: unrecognized declaration introducer [UnrecognizedDecl]
// CHECK:STDERR: struct X { fn () }
// CHECK:STDERR: ^~~~~~
// CHECK:STDERR:
struct X { fn () }
fn F();

// --- fail_with_identifier_as_param.carbon

// CHECK:STDERR: fail_with_identifier_as_param.carbon:[[@LINE+4]]:11: error: expected `:`, `:!`, or `:?` in binding pattern [ExpectedBindingPattern]
// CHECK:STDERR: fn foo(bar);
// CHECK:STDERR:           ^
// CHECK:STDERR:
fn foo(bar);

// --- fail_without_name_and_many_tokens_in_params.carbon

// CHECK:STDERR: fail_without_name_and_many_tokens_in_params.carbon:[[@LINE+4]]:4: error: `fn` introducer should be followed by a name [ExpectedDeclName]
// CHECK:STDERR: fn (a tokens c d e f g h i j k l m n o p q r s t u v w x y z);
// CHECK:STDERR:    ^
// CHECK:STDERR:
fn (a tokens c d e f g h i j k l m n o p q r s t u v w x y z);

// --- form_parameter.carbon

fn FormParam(x:? Form);
fn ComplexFormParam(x:? X.Y(Z));

// --- fail_ref_on_form_parameter.carbon

// CHECK:STDERR: fail_ref_on_form_parameter.carbon:[[@LINE+4]]:6: error: expected `:` binding after `ref` [ExpectedRuntimeBindingPatternAfterRef]
// CHECK:STDERR: fn F(ref x:? Form);
// CHECK:STDERR:      ^~~
// CHECK:STDERR:
fn F(ref x:? Form);

// --- fail_form_within_var.carbon

// CHECK:STDERR: fail_form_within_var.carbon:[[@LINE+4]]:26: error: found `:?` pattern inside `var` pattern [NonRegularBindingInVarDecl]
// CHECK:STDERR: fn FormInVar(var x:? Form);
// CHECK:STDERR:                          ^
// CHECK:STDERR:
fn FormInVar(var x:? Form);

// --- return_form.carbon

fn SimpleReturnForm() ->? Form;
fn ComplexReturnForm() ->? X.Y(Z);

// CHECK:STDOUT: - filename: basic.carbon
// CHECK:STDOUT:   parse_tree: [
// CHECK:STDOUT:     {kind: 'FileStart', text: ''},
// CHECK:STDOUT:       {kind: 'FunctionIntroducer', text: 'fn'},
// CHECK:STDOUT:       {kind: 'IdentifierNameMaybeBeforeSignature', text: 'F'},
// CHECK:STDOUT:         {kind: 'ExplicitParamListStart', text: '('},
// CHECK:STDOUT:       {kind: 'ExplicitParamList', text: ')', subtree_size: 2},
// CHECK:STDOUT:     {kind: 'FunctionDecl', text: ';', subtree_size: 5},
// CHECK:STDOUT:     {kind: 'FileEnd', text: ''},
// CHECK:STDOUT:   ]
// CHECK:STDOUT: - filename: ref.carbon
// CHECK:STDOUT:   parse_tree: [
// CHECK:STDOUT:     {kind: 'FileStart', text: ''},
// CHECK:STDOUT:       {kind: 'FunctionIntroducer', text: 'fn'},
// CHECK:STDOUT:       {kind: 'IdentifierNameMaybeBeforeSignature', text: 'foo'},
// CHECK:STDOUT:         {kind: 'ExplicitParamListStart', text: '('},
// CHECK:STDOUT:             {kind: 'IdentifierNameNotBeforeSignature', text: 'a'},
// CHECK:STDOUT:           {kind: 'RefBindingName', text: 'ref', subtree_size: 2},
// CHECK:STDOUT:           {kind: 'IntTypeLiteral', text: 'i32'},
// CHECK:STDOUT:         {kind: 'LetBindingPattern', text: ':', subtree_size: 4},
// CHECK:STDOUT:       {kind: 'ExplicitParamList', text: ')', subtree_size: 6},
// CHECK:STDOUT:     {kind: 'FunctionDecl', text: ';', subtree_size: 9},
// CHECK:STDOUT:     {kind: 'FileEnd', text: ''},
// CHECK:STDOUT:   ]
// CHECK:STDOUT: - filename: implicit_empty.carbon
// CHECK:STDOUT:   parse_tree: [
// CHECK:STDOUT:     {kind: 'FileStart', text: ''},
// CHECK:STDOUT:       {kind: 'FunctionIntroducer', text: 'fn'},
// CHECK:STDOUT:       {kind: 'IdentifierNameMaybeBeforeSignature', text: 'foo'},
// CHECK:STDOUT:         {kind: 'ImplicitParamListStart', text: '['},
// CHECK:STDOUT:       {kind: 'ImplicitParamList', text: ']', subtree_size: 2},
// CHECK:STDOUT:         {kind: 'ExplicitParamListStart', text: '('},
// CHECK:STDOUT:       {kind: 'ExplicitParamList', text: ')', subtree_size: 2},
// CHECK:STDOUT:     {kind: 'FunctionDecl', text: ';', subtree_size: 7},
// CHECK:STDOUT:     {kind: 'FileEnd', text: ''},
// CHECK:STDOUT:   ]
// CHECK:STDOUT: - filename: implicit_params.carbon
// CHECK:STDOUT:   parse_tree: [
// CHECK:STDOUT:     {kind: 'FileStart', text: ''},
// CHECK:STDOUT:       {kind: 'FunctionIntroducer', text: 'fn'},
// CHECK:STDOUT:       {kind: 'IdentifierNameMaybeBeforeSignature', text: 'foo'},
// CHECK:STDOUT:         {kind: 'ImplicitParamListStart', text: '['},
// CHECK:STDOUT:           {kind: 'IdentifierNameNotBeforeSignature', text: 'a'},
// CHECK:STDOUT:           {kind: 'IntTypeLiteral', text: 'i32'},
// CHECK:STDOUT:         {kind: 'LetBindingPattern', text: ':', subtree_size: 3},
// CHECK:STDOUT:         {kind: 'PatternListComma', text: ','},
// CHECK:STDOUT:           {kind: 'IdentifierNameNotBeforeSignature', text: 'b'},
// CHECK:STDOUT:           {kind: 'IntTypeLiteral', text: 'i32'},
// CHECK:STDOUT:         {kind: 'LetBindingPattern', text: ':', subtree_size: 3},
// CHECK:STDOUT:       {kind: 'ImplicitParamList', text: ']', subtree_size: 9},
// CHECK:STDOUT:         {kind: 'ExplicitParamListStart', text: '('},
// CHECK:STDOUT:       {kind: 'ExplicitParamList', text: ')', subtree_size: 2},
// CHECK:STDOUT:     {kind: 'FunctionDecl', text: ';', subtree_size: 14},
// CHECK:STDOUT:     {kind: 'FileEnd', text: ''},
// CHECK:STDOUT:   ]
// CHECK:STDOUT: - filename: no_params.carbon
// CHECK:STDOUT:   parse_tree: [
// CHECK:STDOUT:     {kind: 'FileStart', text: ''},
// CHECK:STDOUT:         {kind: 'FunctionIntroducer', text: 'fn'},
// CHECK:STDOUT:         {kind: 'IdentifierNameNotBeforeSignature', text: 'foo'},
// CHECK:STDOUT:       {kind: 'FunctionDefinitionStart', text: '{', subtree_size: 3},
// CHECK:STDOUT:     {kind: 'FunctionDefinition', text: '}', subtree_size: 4},
// CHECK:STDOUT:     {kind: 'FileEnd', text: ''},
// CHECK:STDOUT:   ]
// CHECK:STDOUT: - filename: params.carbon
// CHECK:STDOUT:   parse_tree: [
// CHECK:STDOUT:     {kind: 'FileStart', text: ''},
// CHECK:STDOUT:       {kind: 'FunctionIntroducer', text: 'fn'},
// CHECK:STDOUT:       {kind: 'IdentifierNameMaybeBeforeSignature', text: 'foo'},
// CHECK:STDOUT:         {kind: 'ExplicitParamListStart', text: '('},
// CHECK:STDOUT:           {kind: 'IdentifierNameNotBeforeSignature', text: 'a'},
// CHECK:STDOUT:           {kind: 'IntTypeLiteral', text: 'i32'},
// CHECK:STDOUT:         {kind: 'LetBindingPattern', text: ':', subtree_size: 3},
// CHECK:STDOUT:         {kind: 'PatternListComma', text: ','},
// CHECK:STDOUT:           {kind: 'IdentifierNameNotBeforeSignature', text: 'b'},
// CHECK:STDOUT:           {kind: 'IntTypeLiteral', text: 'i32'},
// CHECK:STDOUT:         {kind: 'LetBindingPattern', text: ':', subtree_size: 3},
// CHECK:STDOUT:       {kind: 'ExplicitParamList', text: ')', subtree_size: 9},
// CHECK:STDOUT:     {kind: 'FunctionDecl', text: ';', subtree_size: 12},
// CHECK:STDOUT:     {kind: 'FileEnd', text: ''},
// CHECK:STDOUT:   ]
// CHECK:STDOUT: - filename: with_return_type.carbon
// CHECK:STDOUT:   parse_tree: [
// CHECK:STDOUT:     {kind: 'FileStart', text: ''},
// CHECK:STDOUT:       {kind: 'FunctionIntroducer', text: 'fn'},
// CHECK:STDOUT:       {kind: 'IdentifierNameMaybeBeforeSignature', text: 'foo'},
// CHECK:STDOUT:         {kind: 'ExplicitParamListStart', text: '('},
// CHECK:STDOUT:       {kind: 'ExplicitParamList', text: ')', subtree_size: 2},
// CHECK:STDOUT:         {kind: 'UnsignedIntTypeLiteral', text: 'u32'},
// CHECK:STDOUT:       {kind: 'ReturnType', text: '->', subtree_size: 2},
// CHECK:STDOUT:     {kind: 'FunctionDecl', text: ';', subtree_size: 7},
// CHECK:STDOUT:     {kind: 'FileEnd', text: ''},
// CHECK:STDOUT:   ]
// CHECK:STDOUT: - filename: impl_fn.carbon
// CHECK:STDOUT:   parse_tree: [
// CHECK:STDOUT:     {kind: 'FileStart', text: ''},
// CHECK:STDOUT:       {kind: 'FunctionIntroducer', text: 'fn'},
// CHECK:STDOUT:       {kind: 'OverrideModifier', text: 'override'},
// CHECK:STDOUT:       {kind: 'IdentifierNameMaybeBeforeSignature', text: 'F'},
// CHECK:STDOUT:         {kind: 'ExplicitParamListStart', text: '('},
// CHECK:STDOUT:       {kind: 'ExplicitParamList', text: ')', subtree_size: 2},
// CHECK:STDOUT:     {kind: 'FunctionDecl', text: ';', subtree_size: 6},
// CHECK:STDOUT:       {kind: 'FunctionIntroducer', text: 'fn'},
// CHECK:STDOUT:       {kind: 'AbstractModifier', text: 'abstract'},
// CHECK:STDOUT:       {kind: 'OverrideModifier', text: 'override'},
// CHECK:STDOUT:       {kind: 'IdentifierNameMaybeBeforeSignature', text: 'G'},
// CHECK:STDOUT:         {kind: 'ExplicitParamListStart', text: '('},
// CHECK:STDOUT:       {kind: 'ExplicitParamList', text: ')', subtree_size: 2},
// CHECK:STDOUT:     {kind: 'FunctionDecl', text: ';', subtree_size: 7},
// CHECK:STDOUT:       {kind: 'FunctionIntroducer', text: 'fn'},
// CHECK:STDOUT:       {kind: 'OverrideModifier', text: 'override'},
// CHECK:STDOUT:       {kind: 'AbstractModifier', text: 'abstract'},
// CHECK:STDOUT:       {kind: 'IdentifierNameMaybeBeforeSignature', text: 'H'},
// CHECK:STDOUT:         {kind: 'ExplicitParamListStart', text: '('},
// CHECK:STDOUT:       {kind: 'ExplicitParamList', text: ')', subtree_size: 2},
// CHECK:STDOUT:     {kind: 'FunctionDecl', text: ';', subtree_size: 7},
// CHECK:STDOUT:       {kind: 'FunctionIntroducer', text: 'fn'},
// CHECK:STDOUT:       {kind: 'PrivateModifier', text: 'private'},
// CHECK:STDOUT:       {kind: 'OverrideModifier', text: 'override'},
// CHECK:STDOUT:       {kind: 'DefaultModifier', text: 'default'},
// CHECK:STDOUT:       {kind: 'IdentifierNameMaybeBeforeSignature', text: 'I'},
// CHECK:STDOUT:         {kind: 'ExplicitParamListStart', text: '('},
// CHECK:STDOUT:       {kind: 'ExplicitParamList', text: ')', subtree_size: 2},
// CHECK:STDOUT:     {kind: 'FunctionDecl', text: ';', subtree_size: 8},
// CHECK:STDOUT:     {kind: 'FileEnd', text: ''},
// CHECK:STDOUT:   ]
// CHECK:STDOUT: - filename: fail_identifier_instead_of_sig.carbon
// CHECK:STDOUT:   parse_tree: [
// CHECK:STDOUT:     {kind: 'FileStart', text: ''},
// CHECK:STDOUT:       {kind: 'FunctionIntroducer', text: 'fn'},
// CHECK:STDOUT:       {kind: 'IdentifierNameNotBeforeSignature', text: 'foo'},
// CHECK:STDOUT:     {kind: 'FunctionDecl', text: ';', has_error: yes, subtree_size: 3},
// CHECK:STDOUT:     {kind: 'FileEnd', text: ''},
// CHECK:STDOUT:   ]
// CHECK:STDOUT: - filename: fail_missing_implicit_close.carbon
// CHECK:STDOUT:   parse_tree: [
// CHECK:STDOUT:     {kind: 'FileStart', text: ''},
// CHECK:STDOUT:       {kind: 'FunctionIntroducer', text: 'fn'},
// CHECK:STDOUT:       {kind: 'IdentifierNameNotBeforeSignature', text: 'Div'},
// CHECK:STDOUT:     {kind: 'FunctionDecl', text: ';', has_error: yes, subtree_size: 3},
// CHECK:STDOUT:     {kind: 'FileEnd', text: ''},
// CHECK:STDOUT:   ]
// CHECK:STDOUT: - filename: fail_missing_name.carbon
// CHECK:STDOUT:   parse_tree: [
// CHECK:STDOUT:     {kind: 'FileStart', text: ''},
// CHECK:STDOUT:       {kind: 'FunctionIntroducer', text: 'fn'},
// CHECK:STDOUT:       {kind: 'InvalidParse', text: '(', has_error: yes},
// CHECK:STDOUT:     {kind: 'FunctionDecl', text: ';', has_error: yes, subtree_size: 3},
// CHECK:STDOUT:     {kind: 'FileEnd', text: ''},
// CHECK:STDOUT:   ]
// CHECK:STDOUT: - filename: fail_no_sig_or_semi.carbon
// CHECK:STDOUT:   parse_tree: [
// CHECK:STDOUT:     {kind: 'FileStart', text: ''},
// CHECK:STDOUT:       {kind: 'FunctionIntroducer', text: 'fn'},
// CHECK:STDOUT:       {kind: 'IdentifierNameNotBeforeSignature', text: 'foo'},
// CHECK:STDOUT:     {kind: 'FunctionDecl', text: 'fn', has_error: yes, subtree_size: 3},
// CHECK:STDOUT:     {kind: 'FileEnd', text: ''},
// CHECK:STDOUT:   ]
// CHECK:STDOUT: - filename: fail_only_fn_and_semi.carbon
// CHECK:STDOUT:   parse_tree: [
// CHECK:STDOUT:     {kind: 'FileStart', text: ''},
// CHECK:STDOUT:       {kind: 'FunctionIntroducer', text: 'fn'},
// CHECK:STDOUT:       {kind: 'InvalidParse', text: ';', has_error: yes},
// CHECK:STDOUT:     {kind: 'FunctionDecl', text: ';', has_error: yes, subtree_size: 3},
// CHECK:STDOUT:     {kind: 'FileEnd', text: ''},
// CHECK:STDOUT:   ]
// CHECK:STDOUT: - filename: fail_repeated_fn_and_semi.carbon
// CHECK:STDOUT:   parse_tree: [
// CHECK:STDOUT:     {kind: 'FileStart', text: ''},
// CHECK:STDOUT:       {kind: 'FunctionIntroducer', text: 'fn'},
// CHECK:STDOUT:       {kind: 'InvalidParse', text: 'fn', has_error: yes},
// CHECK:STDOUT:     {kind: 'FunctionDecl', text: ';', has_error: yes, subtree_size: 3},
// CHECK:STDOUT:     {kind: 'FileEnd', text: ''},
// CHECK:STDOUT:   ]
// CHECK:STDOUT: - filename: fail_skip_indented_newline_until_outdent.carbon
// CHECK:STDOUT:   parse_tree: [
// CHECK:STDOUT:     {kind: 'FileStart', text: ''},
// CHECK:STDOUT:       {kind: 'FunctionIntroducer', text: 'fn'},
// CHECK:STDOUT:       {kind: 'InvalidParse', text: '(', has_error: yes},
// CHECK:STDOUT:     {kind: 'FunctionDecl', text: ')', has_error: yes, subtree_size: 3},
// CHECK:STDOUT:       {kind: 'FunctionIntroducer', text: 'fn'},
// CHECK:STDOUT:       {kind: 'IdentifierNameMaybeBeforeSignature', text: 'F'},
// CHECK:STDOUT:         {kind: 'ExplicitParamListStart', text: '('},
// CHECK:STDOUT:       {kind: 'ExplicitParamList', text: ')', subtree_size: 2},
// CHECK:STDOUT:     {kind: 'FunctionDecl', text: ';', subtree_size: 5},
// CHECK:STDOUT:     {kind: 'FileEnd', text: ''},
// CHECK:STDOUT:   ]
// CHECK:STDOUT: - filename: fail_skip_indented_newline_with_semi.carbon
// CHECK:STDOUT:   parse_tree: [
// CHECK:STDOUT:     {kind: 'FileStart', text: ''},
// CHECK:STDOUT:       {kind: 'FunctionIntroducer', text: 'fn'},
// CHECK:STDOUT:       {kind: 'InvalidParse', text: '(', has_error: yes},
// CHECK:STDOUT:     {kind: 'FunctionDecl', text: ';', has_error: yes, subtree_size: 3},
// CHECK:STDOUT:       {kind: 'FunctionIntroducer', text: 'fn'},
// CHECK:STDOUT:       {kind: 'IdentifierNameMaybeBeforeSignature', text: 'F'},
// CHECK:STDOUT:         {kind: 'ExplicitParamListStart', text: '('},
// CHECK:STDOUT:       {kind: 'ExplicitParamList', text: ')', subtree_size: 2},
// CHECK:STDOUT:     {kind: 'FunctionDecl', text: ';', subtree_size: 5},
// CHECK:STDOUT:     {kind: 'FileEnd', text: ''},
// CHECK:STDOUT:   ]
// CHECK:STDOUT: - filename: fail_skip_indented_newline_without_semi.carbon
// CHECK:STDOUT:   parse_tree: [
// CHECK:STDOUT:     {kind: 'FileStart', text: ''},
// CHECK:STDOUT:       {kind: 'FunctionIntroducer', text: 'fn'},
// CHECK:STDOUT:       {kind: 'InvalidParse', text: '(', has_error: yes},
// CHECK:STDOUT:     {kind: 'FunctionDecl', text: ')', has_error: yes, subtree_size: 3},
// CHECK:STDOUT:       {kind: 'FunctionIntroducer', text: 'fn'},
// CHECK:STDOUT:       {kind: 'IdentifierNameMaybeBeforeSignature', text: 'F'},
// CHECK:STDOUT:         {kind: 'ExplicitParamListStart', text: '('},
// CHECK:STDOUT:       {kind: 'ExplicitParamList', text: ')', subtree_size: 2},
// CHECK:STDOUT:     {kind: 'FunctionDecl', text: ';', subtree_size: 5},
// CHECK:STDOUT:     {kind: 'FileEnd', text: ''},
// CHECK:STDOUT:   ]
// CHECK:STDOUT: - filename: fail_skip_to_newline_without_semi.carbon
// CHECK:STDOUT:   parse_tree: [
// CHECK:STDOUT:     {kind: 'FileStart', text: ''},
// CHECK:STDOUT:       {kind: 'FunctionIntroducer', text: 'fn'},
// CHECK:STDOUT:       {kind: 'InvalidParse', text: '(', has_error: yes},
// CHECK:STDOUT:     {kind: 'FunctionDecl', text: ')', has_error: yes, subtree_size: 3},
// CHECK:STDOUT:       {kind: 'FunctionIntroducer', text: 'fn'},
// CHECK:STDOUT:       {kind: 'IdentifierNameMaybeBeforeSignature', text: 'F'},
// CHECK:STDOUT:         {kind: 'ExplicitParamListStart', text: '('},
// CHECK:STDOUT:       {kind: 'ExplicitParamList', text: ')', subtree_size: 2},
// CHECK:STDOUT:     {kind: 'FunctionDecl', text: ';', subtree_size: 5},
// CHECK:STDOUT:     {kind: 'FileEnd', text: ''},
// CHECK:STDOUT:   ]
// CHECK:STDOUT: - filename: fail_skip_without_semi_to_curly.carbon
// CHECK:STDOUT:   parse_tree: [
// CHECK:STDOUT:     {kind: 'FileStart', text: ''},
// CHECK:STDOUT:       {kind: 'InvalidParseStart', text: 'struct', has_error: yes},
// CHECK:STDOUT:     {kind: 'InvalidParseSubtree', text: '}', has_error: yes, subtree_size: 2},
// CHECK:STDOUT:       {kind: 'FunctionIntroducer', text: 'fn'},
// CHECK:STDOUT:       {kind: 'IdentifierNameMaybeBeforeSignature', text: 'F'},
// CHECK:STDOUT:         {kind: 'ExplicitParamListStart', text: '('},
// CHECK:STDOUT:       {kind: 'ExplicitParamList', text: ')', subtree_size: 2},
// CHECK:STDOUT:     {kind: 'FunctionDecl', text: ';', subtree_size: 5},
// CHECK:STDOUT:     {kind: 'FileEnd', text: ''},
// CHECK:STDOUT:   ]
// CHECK:STDOUT: - filename: fail_with_identifier_as_param.carbon
// CHECK:STDOUT:   parse_tree: [
// CHECK:STDOUT:     {kind: 'FileStart', text: ''},
// CHECK:STDOUT:       {kind: 'FunctionIntroducer', text: 'fn'},
// CHECK:STDOUT:       {kind: 'IdentifierNameMaybeBeforeSignature', text: 'foo'},
// CHECK:STDOUT:         {kind: 'ExplicitParamListStart', text: '('},
// CHECK:STDOUT:           {kind: 'IdentifierNameNotBeforeSignature', text: 'bar'},
// CHECK:STDOUT:           {kind: 'InvalidParse', text: ')', has_error: yes},
// CHECK:STDOUT:         {kind: 'LetBindingPattern', text: 'bar', has_error: yes, subtree_size: 3},
// CHECK:STDOUT:       {kind: 'ExplicitParamList', text: ')', has_error: yes, subtree_size: 5},
// CHECK:STDOUT:     {kind: 'FunctionDecl', text: ';', subtree_size: 8},
// CHECK:STDOUT:     {kind: 'FileEnd', text: ''},
// CHECK:STDOUT:   ]
// CHECK:STDOUT: - filename: fail_without_name_and_many_tokens_in_params.carbon
// CHECK:STDOUT:   parse_tree: [
// CHECK:STDOUT:     {kind: 'FileStart', text: ''},
// CHECK:STDOUT:       {kind: 'FunctionIntroducer', text: 'fn'},
// CHECK:STDOUT:       {kind: 'InvalidParse', text: '(', has_error: yes},
// CHECK:STDOUT:     {kind: 'FunctionDecl', text: ';', has_error: yes, subtree_size: 3},
// CHECK:STDOUT:     {kind: 'FileEnd', text: ''},
// CHECK:STDOUT:   ]
// CHECK:STDOUT: - filename: form_parameter.carbon
// CHECK:STDOUT:   parse_tree: [
// CHECK:STDOUT:     {kind: 'FileStart', text: ''},
// CHECK:STDOUT:       {kind: 'FunctionIntroducer', text: 'fn'},
// CHECK:STDOUT:       {kind: 'IdentifierNameMaybeBeforeSignature', text: 'FormParam'},
// CHECK:STDOUT:         {kind: 'ExplicitParamListStart', text: '('},
// CHECK:STDOUT:           {kind: 'IdentifierNameNotBeforeSignature', text: 'x'},
// CHECK:STDOUT:           {kind: 'IdentifierNameExpr', text: 'Form'},
// CHECK:STDOUT:         {kind: 'FormBindingPattern', text: ':?', subtree_size: 3},
// CHECK:STDOUT:       {kind: 'ExplicitParamList', text: ')', subtree_size: 5},
// CHECK:STDOUT:     {kind: 'FunctionDecl', text: ';', subtree_size: 8},
// CHECK:STDOUT:       {kind: 'FunctionIntroducer', text: 'fn'},
// CHECK:STDOUT:       {kind: 'IdentifierNameMaybeBeforeSignature', text: 'ComplexFormParam'},
// CHECK:STDOUT:         {kind: 'ExplicitParamListStart', text: '('},
// CHECK:STDOUT:           {kind: 'IdentifierNameNotBeforeSignature', text: 'x'},
// CHECK:STDOUT:                 {kind: 'IdentifierNameExpr', text: 'X'},
// CHECK:STDOUT:                 {kind: 'IdentifierNameNotBeforeSignature', text: 'Y'},
// CHECK:STDOUT:               {kind: 'MemberAccessExpr', text: '.', subtree_size: 3},
// CHECK:STDOUT:             {kind: 'CallExprStart', text: '(', subtree_size: 4},
// CHECK:STDOUT:             {kind: 'IdentifierNameExpr', text: 'Z'},
// CHECK:STDOUT:           {kind: 'CallExpr', text: ')', subtree_size: 6},
// CHECK:STDOUT:         {kind: 'FormBindingPattern', text: ':?', subtree_size: 8},
// CHECK:STDOUT:       {kind: 'ExplicitParamList', text: ')', subtree_size: 10},
// CHECK:STDOUT:     {kind: 'FunctionDecl', text: ';', subtree_size: 13},
// CHECK:STDOUT:     {kind: 'FileEnd', text: ''},
// CHECK:STDOUT:   ]
// CHECK:STDOUT: - filename: fail_ref_on_form_parameter.carbon
// CHECK:STDOUT:   parse_tree: [
// CHECK:STDOUT:     {kind: 'FileStart', text: ''},
// CHECK:STDOUT:       {kind: 'FunctionIntroducer', text: 'fn'},
// CHECK:STDOUT:       {kind: 'IdentifierNameMaybeBeforeSignature', text: 'F'},
// CHECK:STDOUT:         {kind: 'ExplicitParamListStart', text: '('},
// CHECK:STDOUT:             {kind: 'IdentifierNameNotBeforeSignature', text: 'x'},
// CHECK:STDOUT:           {kind: 'RefBindingName', text: 'ref', has_error: yes, subtree_size: 2},
// CHECK:STDOUT:           {kind: 'IdentifierNameExpr', text: 'Form'},
// CHECK:STDOUT:         {kind: 'FormBindingPattern', text: ':?', has_error: yes, subtree_size: 4},
// CHECK:STDOUT:       {kind: 'ExplicitParamList', text: ')', has_error: yes, subtree_size: 6},
// CHECK:STDOUT:     {kind: 'FunctionDecl', text: ';', subtree_size: 9},
// CHECK:STDOUT:     {kind: 'FileEnd', text: ''},
// CHECK:STDOUT:   ]
// CHECK:STDOUT: - filename: fail_form_within_var.carbon
// CHECK:STDOUT:   parse_tree: [
// CHECK:STDOUT:     {kind: 'FileStart', text: ''},
// CHECK:STDOUT:       {kind: 'FunctionIntroducer', text: 'fn'},
// CHECK:STDOUT:       {kind: 'IdentifierNameMaybeBeforeSignature', text: 'FormInVar'},
// CHECK:STDOUT:         {kind: 'ExplicitParamListStart', text: '('},
// CHECK:STDOUT:             {kind: 'IdentifierNameNotBeforeSignature', text: 'x'},
// CHECK:STDOUT:             {kind: 'IdentifierNameExpr', text: 'Form'},
// CHECK:STDOUT:           {kind: 'VarBindingPattern', text: ':?', has_error: yes, subtree_size: 3},
// CHECK:STDOUT:         {kind: 'VariablePattern', text: 'var', has_error: yes, subtree_size: 4},
// CHECK:STDOUT:       {kind: 'ExplicitParamList', text: ')', has_error: yes, subtree_size: 6},
// CHECK:STDOUT:     {kind: 'FunctionDecl', text: ';', subtree_size: 9},
// CHECK:STDOUT:     {kind: 'FileEnd', text: ''},
// CHECK:STDOUT:   ]
// CHECK:STDOUT: - filename: return_form.carbon
// CHECK:STDOUT:   parse_tree: [
// CHECK:STDOUT:     {kind: 'FileStart', text: ''},
// CHECK:STDOUT:       {kind: 'FunctionIntroducer', text: 'fn'},
// CHECK:STDOUT:       {kind: 'IdentifierNameMaybeBeforeSignature', text: 'SimpleReturnForm'},
// CHECK:STDOUT:         {kind: 'ExplicitParamListStart', text: '('},
// CHECK:STDOUT:       {kind: 'ExplicitParamList', text: ')', subtree_size: 2},
// CHECK:STDOUT:         {kind: 'IdentifierNameExpr', text: 'Form'},
// CHECK:STDOUT:       {kind: 'ReturnForm', text: '->?', subtree_size: 2},
// CHECK:STDOUT:     {kind: 'FunctionDecl', text: ';', subtree_size: 7},
// CHECK:STDOUT:       {kind: 'FunctionIntroducer', text: 'fn'},
// CHECK:STDOUT:       {kind: 'IdentifierNameMaybeBeforeSignature', text: 'ComplexReturnForm'},
// CHECK:STDOUT:         {kind: 'ExplicitParamListStart', text: '('},
// CHECK:STDOUT:       {kind: 'ExplicitParamList', text: ')', subtree_size: 2},
// CHECK:STDOUT:               {kind: 'IdentifierNameExpr', text: 'X'},
// CHECK:STDOUT:               {kind: 'IdentifierNameNotBeforeSignature', text: 'Y'},
// CHECK:STDOUT:             {kind: 'MemberAccessExpr', text: '.', subtree_size: 3},
// CHECK:STDOUT:           {kind: 'CallExprStart', text: '(', subtree_size: 4},
// CHECK:STDOUT:           {kind: 'IdentifierNameExpr', text: 'Z'},
// CHECK:STDOUT:         {kind: 'CallExpr', text: ')', subtree_size: 6},
// CHECK:STDOUT:       {kind: 'ReturnForm', text: '->?', subtree_size: 7},
// CHECK:STDOUT:     {kind: 'FunctionDecl', text: ';', subtree_size: 12},
// CHECK:STDOUT:     {kind: 'FileEnd', text: ''},
// CHECK:STDOUT:   ]