build: allow IWYU to fix includes for all .c files

Allow Include What You Use to remove unnecessary includes and only
include what is necessary. This helps with reducing compilation times
and makes it easier to visualise which dependencies are actually
required.

Work on https://github.com/neovim/neovim/issues/549, but doesn't close
it since this only works fully for .c files and not headers.

4 files changed, 11 insertions, 1 deletions

diff --git a/src/nvim/viml/parser/expressions.c b/src/nvim/viml/parser/expressions.c
index 77f85b5d2d..24dfb38ae0 100644
--- a/src/nvim/viml/parser/expressions.c
+++ b/src/nvim/viml/parser/expressions.c
@@ -53,6 +53,8 @@
 #include <assert.h>
 #include <stdbool.h>
 #include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 
 #include "klib/kvec.h"
@@ -60,6 +62,10 @@
 #include "nvim/assert.h"
 #include "nvim/charset.h"
 #include "nvim/eval/typval.h"
+#include "nvim/gettext.h"
+#include "nvim/keycodes.h"
+#include "nvim/macros.h"
+#include "nvim/mbyte.h"
 #include "nvim/memory.h"
 #include "nvim/types.h"
 #include "nvim/vim.h"
diff --git a/src/nvim/viml/parser/expressions.h b/src/nvim/viml/parser/expressions.h
index 77fbfa615f..6fe6a784a0 100644
--- a/src/nvim/viml/parser/expressions.h
+++ b/src/nvim/viml/parser/expressions.h
@@ -6,9 +6,12 @@
 #include <stdint.h>
 
 #include "nvim/eval/typval.h"
+#include "nvim/eval/typval_defs.h"
 #include "nvim/types.h"
 #include "nvim/viml/parser/parser.h"
 
+struct expr_ast_node;
+
 // Defines whether to ignore case:
 //    ==   kCCStrategyUseOption
 //    ==#  kCCStrategyMatchCase
diff --git a/src/nvim/viml/parser/parser.c b/src/nvim/viml/parser/parser.c
index a41b750e76..1547feba90 100644
--- a/src/nvim/viml/parser/parser.c
+++ b/src/nvim/viml/parser/parser.c
@@ -4,7 +4,7 @@
 #include "nvim/viml/parser/parser.h"
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
-# include "viml/parser/parser.c.generated.h"
+# include "viml/parser/parser.c.generated.h"  // IWYU pragma: export
 #endif
 
 void parser_simple_get_line(void *cookie, ParserLine *ret_pline)
diff --git a/src/nvim/viml/parser/parser.h b/src/nvim/viml/parser/parser.h
index 56e8b2d32b..f387301c2d 100644
--- a/src/nvim/viml/parser/parser.h
+++ b/src/nvim/viml/parser/parser.h
@@ -8,6 +8,7 @@
 #include "klib/kvec.h"
 #include "nvim/func_attr.h"
 #include "nvim/mbyte.h"
+#include "nvim/mbyte_defs.h"
 #include "nvim/memory.h"
 
 /// One parsed line