blocks with one statement pass constant expression eval

src/analyze.cpp

@@ -4720,6 +4720,18 @@ static TypeTableEntry *analyze_block_expr(CodeGen *g, ImportTableEntry *import,
         }
     }
     node->data.block.nested_block = child_context;
+
+    ConstExprValue *const_val = &node->data.block.resolved_expr.const_val;
+    if (node->data.block.statements.length == 0) {
+        const_val->ok = true;
+    } else if (node->data.block.statements.length == 1) {
+        AstNode *only_node = node->data.block.statements.at(0);
+        ConstExprValue *other_const_val = &get_resolved_expr(only_node)->const_val;
+        if (other_const_val->ok) {
+            *const_val = *other_const_val;
+        }
+    }
+
     return return_type;
 }
 

std/rand.zig

@@ -58,6 +58,10 @@ pub struct Rand {
         return f32(r.range_u64(0, precision)) / precision;
     }
 
+    pub fn boolean(r: &Rand) -> bool {
+        return (r.get_u32() & 0x1) == 1;
+    }
+
     fn generate_numbers(r: &Rand) {
         for (r.array) |item, i| {
             const y : u32 = (item & 0x80000000) + (r.array[(i + 1) % ARRAY_SIZE] & 0x7fffffff);

test/self_hosted.zig

@@ -215,3 +215,21 @@ fn explicit_cast_maybe_pointers() {
     const a: ?&i32 = undefined;
     const b: ?&f32 = (?&f32)(a);
 }
+
+
+#attribute("test")
+fn const_expr_eval_on_single_expr_blocks() {
+    if (const_expr_eval_on_single_expr_blocks_fn(1, true) != 3) unreachable{}
+}
+
+fn const_expr_eval_on_single_expr_blocks_fn(x: i32, b: bool) -> i32 {
+    const literal = 3;
+
+    const result = if (b) {
+        literal
+    } else {
+        x
+    };
+
+    return result;
+}