From 7449bbf4e10b5db5b311d11a9ffa698252ee4aa0 Mon Sep 17 00:00:00 2001
From: Jim Blandy <jimb@red-bean.com>
Date: Tue, 10 Oct 2023 14:44:27 -0700
Subject: [PATCH] fixup! add an expression constness tracker

---
 src/front/glsl/parser/declarations.rs         | 27 ++++++++++++-------
 .../out/wgsl/local-var-init-in-loop.comp.wgsl |  5 ++--
 2 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/src/front/glsl/parser/declarations.rs b/src/front/glsl/parser/declarations.rs
index b53616b8f4..02ee2bedea 100644
--- a/src/front/glsl/parser/declarations.rs
+++ b/src/front/glsl/parser/declarations.rs
@@ -246,19 +246,26 @@ impl<'source> ParsingContext<'source> {
                 })
                 .transpose()?;
 
-            let (decl_initializer, late_initializer) = if is_global_const {
-                (init, None)
+            let decl_initializer;
+            let late_initializer;
+            if is_global_const {
+                decl_initializer = init;
+                late_initializer = None;
             } else if ctx.external {
-                let decl_initializer =
+                decl_initializer =
                     init.and_then(|expr| ctx.ctx.lift_up_const_expression(expr).ok());
-                (decl_initializer, None)
+                late_initializer = None;
+            } else if let Some(init) = init {
+                if ctx.is_inside_loop || !ctx.ctx.expression_constness.is_const(init) {
+                    decl_initializer = None;
+                    late_initializer = Some(init);
+                } else {
+                    decl_initializer = Some(init);
+                    late_initializer = None;
+                }
             } else {
-                let decl_initializer =
-                    init.filter(|expr| ctx.ctx.expression_constness.is_const(*expr));
-                let late_initializer = (decl_initializer.is_none() || ctx.is_inside_loop)
-                    .then_some(init)
-                    .flatten();
-                (decl_initializer, late_initializer)
+                decl_initializer = None;
+                late_initializer = None;
             };
 
             let pointer = ctx.add_var(frontend, ty, name, decl_initializer, meta)?;
diff --git a/tests/out/wgsl/local-var-init-in-loop.comp.wgsl b/tests/out/wgsl/local-var-init-in-loop.comp.wgsl
index 750e32e6d3..7675a54cef 100644
--- a/tests/out/wgsl/local-var-init-in-loop.comp.wgsl
+++ b/tests/out/wgsl/local-var-init-in-loop.comp.wgsl
@@ -1,7 +1,7 @@
 fn main_1() {
     var sum: vec4<f32> = vec4(0.0);
     var i: i32 = 0;
-    var a: vec4<f32> = vec4(1.0);
+    var a: vec4<f32>;
 
     loop {
         let _e6 = i;
@@ -9,8 +9,7 @@ fn main_1() {
             break;
         }
         {
-            let _e15 = vec4(1.0);
-            a = _e15;
+            a = vec4(1.0);
             let _e17 = sum;
             let _e18 = a;
             sum = (_e17 + _e18);