Fix parser warnings order

Cabal-syntax/src/Distribution/Fields/ParseResult.hs

@@ -147,12 +147,12 @@ getCabalSpecVersion = PR $ \s@(PRState _ _ v) _fp _failure success ->
 -- | Add a warning. This doesn't fail the parsing process.
 parseWarning :: Position -> PWarnType -> String -> ParseResult src ()
 parseWarning pos t msg = PR $ \(PRState warns errs v) ctx _failure success ->
-  success (PRState (PWarningWithSource (prContextSource ctx) (PWarning t pos msg) : warns) errs v) ()
+  success (PRState (warns ++ [PWarningWithSource (prContextSource ctx) (PWarning t pos msg)]) errs v) ()
 
 -- | Add multiple warnings at once.
 parseWarnings :: [PWarning] -> ParseResult src ()
 parseWarnings newWarns = PR $ \(PRState warns errs v) ctx _failure success ->
-  success (PRState (map (PWarningWithSource (prContextSource ctx)) newWarns ++ warns) errs v) ()
+  success (PRState (warns ++ map (PWarningWithSource (prContextSource ctx)) newWarns) errs v) ()
 
 -- | Add an error, but not fail the parser yet.
 --

Cabal-tests/tests/ParserTests/regressions/common.format

@@ -1,6 +1,6 @@
-common.cabal:29:3: Unknown field: import. You should set cabal-version: 2.2 or larger to use common stanzas
-common.cabal:20:3: Unknown field: import. You should set cabal-version: 2.2 or larger to use common stanzas
 common.cabal:14:1: Ignoring section: common. You should set cabal-version: 2.2 or larger to use common stanzas.
+common.cabal:20:3: Unknown field: import. You should set cabal-version: 2.2 or larger to use common stanzas
+common.cabal:29:3: Unknown field: import. You should set cabal-version: 2.2 or larger to use common stanzas
 cabal-version:            >=1.10
 name:                     common
 version:                  0

Cabal-tests/tests/ParserTests/regressions/elif.format

@@ -1,5 +1,5 @@
-elif.cabal:19:3: invalid subsection "else"
 elif.cabal:17:3: invalid subsection "elif". You should set cabal-version: 2.2 or larger to use elif-conditionals.
+elif.cabal:19:3: invalid subsection "else"
 cabal-version: >=1.10
 name:          elif
 version:       0

Cabal-tests/tests/ParserTests/regressions/wl-pprint-indef.format

@@ -1,6 +1,6 @@
-wl-pprint-indef.cabal:28:3: The field "mixins" is available only since the Cabal specification version 2.0. This field will be ignored.
-wl-pprint-indef.cabal:27:3: The field "signatures" is available only since the Cabal specification version 2.0. This field will be ignored.
 wl-pprint-indef.cabal:23:3: The field "mixins" is available only since the Cabal specification version 2.0. This field will be ignored.
+wl-pprint-indef.cabal:27:3: The field "signatures" is available only since the Cabal specification version 2.0. This field will be ignored.
+wl-pprint-indef.cabal:28:3: The field "mixins" is available only since the Cabal specification version 2.0. This field will be ignored.
 cabal-version: >=1.6
 name:          wl-pprint-indef
 version:       1.2

changelog.d/issue-11269.md

@@ -0,0 +1,10 @@
+---
+synopsis: Fix parse warnings being emitted in reverse order
+packages: [Cabal-syntax]
+prs: 11479
+issues: 11269
+---
+
+Parse warnings were prepended to the accumulator list, causing them to
+be emitted in reverse file order. They are now appended so they come out
+in file order, consistent with GHC's behavior.