From dcd269782a16e55c284bbd8679c4cb9624656465 Mon Sep 17 00:00:00 2001
From: Systemcluster <me@systemcluster.me>
Date: Sun, 14 Feb 2021 00:29:08 +0100
Subject: [PATCH] [wgsl] restrict type casts to matching container types

---
 src/front/wgsl/mod.rs     | 20 +++++++++++++++-----
 tests/out/shadow.msl.snap | 10 ++++------
 tests/out/skybox.msl.snap |  4 ++--
 3 files changed, 21 insertions(+), 13 deletions(-)

diff --git a/src/front/wgsl/mod.rs b/src/front/wgsl/mod.rs
index e4febf8a08..8275f38ea0 100644
--- a/src/front/wgsl/mod.rs
+++ b/src/front/wgsl/mod.rs
@@ -844,7 +844,6 @@ impl Parser {
                         ctx.constants,
                     )?;
                     let kind = inner.scalar_kind();
-                    let ty = ctx.types.fetch_or_append(crate::Type { name: None, inner });
 
                     lexer.expect(Token::Paren('('))?;
                     let mut components = Vec::new();
@@ -856,13 +855,24 @@ impl Parser {
                     }
                     lexer.expect(Token::Paren(')'))?;
                     if components.is_empty() {
-                        crate::Expression::As {
-                            expr: last_component,
-                            kind: kind.ok_or(Error::BadTypeCast(word))?,
-                            convert: true,
+                        let last_component_inner = ctx.resolve_type(last_component)?;
+                        match (&inner, last_component_inner) {
+                            (crate::TypeInner::Scalar { .. }, crate::TypeInner::Scalar { .. })
+                            | (crate::TypeInner::Matrix { .. }, crate::TypeInner::Matrix { .. })
+                            | (crate::TypeInner::Vector { .. }, crate::TypeInner::Vector { .. }) => {
+                                crate::Expression::As {
+                                    expr: last_component,
+                                    kind: kind.ok_or(Error::BadTypeCast(word))?,
+                                    convert: true,
+                                }
+                            }
+                            _ => {
+                                return Err(Error::BadTypeCast(word));
+                            }
                         }
                     } else {
                         components.push(last_component);
+                        let ty = ctx.types.fetch_or_append(crate::Type { name: None, inner });
                         crate::Expression::Compose { ty, components }
                     }
                 }
diff --git a/tests/out/shadow.msl.snap b/tests/out/shadow.msl.snap
index ccb2a01ba8..400381564b 100644
--- a/tests/out/shadow.msl.snap
+++ b/tests/out/shadow.msl.snap
@@ -37,11 +37,9 @@ typedef float type7;
 
 typedef metal::float2 type8;
 
-typedef int type9;
+typedef metal::float3 type9;
 
-typedef metal::float3 type10;
-
-typedef bool type11;
+typedef bool type10;
 
 type7 fetch_shadow(
     type6 light_id,
@@ -57,7 +55,7 @@ type7 fetch_shadow(
 }
 
 struct fs_mainInput {
-    type10 in_normal_fs [[user(loc0)]];
+    type9 in_normal_fs [[user(loc0)]];
     type2 in_position_fs [[user(loc1)]];
 };
 
@@ -73,7 +71,7 @@ fragment fs_mainOutput fs_main(
     type5 sampler_shadow [[sampler(0)]]
 ) {
     fs_mainOutput output;
-    type10 color1 = type10(0.05, 0.05, 0.05);
+    type9 color1 = type9(0.05, 0.05, 0.05);
     type6 i = 0u;
     bool loop_init = true;
     while(true) {
diff --git a/tests/out/skybox.msl.snap b/tests/out/skybox.msl.snap
index c05cba30ce..bb036f6ac2 100644
--- a/tests/out/skybox.msl.snap
+++ b/tests/out/skybox.msl.snap
@@ -20,9 +20,9 @@ struct Data {
 
 typedef int type4;
 
-typedef float type5;
+typedef metal::float3x3 type5;
 
-typedef metal::float3x3 type6;
+typedef float type6;
 
 typedef metal::texturecube<float, metal::access::sample> type7;