Add support for pointer deduce type

Add regression tests for deduced pointers

Author: filipsajdak

regression-tests/pure2-deduced-pointers.cpp2

@@ -0,0 +1,31 @@
+// workaround for bug where get_declaration_of is skipping first symbol
+bun: () = {}
+
+fun: (inout i:int) -> *int = {
+    return i&;
+}
+
+main: (argc : int, argv : **char) -> int = {
+    a:     int = 2;
+    pa:   *int = a&;
+    ppa: **int = pa&;
+
+    pa = 0;   // caught
+
+    pa2:= ppa*;
+    pa2 = 0;  // caught
+
+    pa3 := a&;
+    pa3 = 0;  // caught
+    pa3 += 2; // caught
+
+    ppa2 := pa2&;
+    pa4 := ppa2*;
+    pa4 = 0;  // caught
+
+    pppa := ppa&;
+    pa5 := pppa**;
+    pa5 = 0;  // caught
+
+    return a*pa**ppa**; // 8
+}

source/cppfront.cpp

@@ -1555,6 +1555,32 @@ class cppfront
     }
 
 
+    //-----------------------------------------------------------------------
+    //
+    auto is_it_pointer_declaration(declaration_sym const* decl, int deref_cnt = 0, int addr_cnt = 0) -> bool {
+        if (!decl || !decl->declaration)
+            return false;
+        if (addr_cnt>deref_cnt)
+            return true;
+
+        if (decl->declaration->dereference) {
+            auto deref = sema.get_declaration_of(*decl->declaration->dereference);
+            return is_it_pointer_declaration(deref, deref_cnt+decl->declaration->dereference_cnt, addr_cnt);
+        } else if (decl->declaration->address_of) {
+            auto addr = sema.get_declaration_of(*decl->declaration->address_of);
+            return is_it_pointer_declaration(addr, deref_cnt, addr_cnt+1);
+        }
+
+        int pointer_declarators_cnt = 0;
+        if (auto* obj_id_expr = std::get_if<declaration_node::object>(&decl->declaration->type)) {
+            if (auto* unqual = std::get_if<id_expression_node::unqualified>(&(*obj_id_expr)->id)){
+                pointer_declarators_cnt = std::ssize((*unqual)->pointer_declarators);
+            }
+        }
+
+        return (pointer_declarators_cnt + addr_cnt - deref_cnt) > 0;
+    };
+
     //-----------------------------------------------------------------------
     //
     auto emit(postfix_expression_node& n, bool for_lambda_capture = false) -> void
@@ -1588,7 +1614,7 @@ class cppfront
 
                 //  TODO: Generalize this -- for now we detect only multi-level cases of the form "p: ***int = ...;"
                 //        We don't recognize pointer types that are deduced or from Cpp1
-                if (!unqual->pointer_declarators.empty() || is_pointer) {
+                if (is_it_pointer_declaration(decl) || !unqual->pointer_declarators.empty() || is_pointer) {
                     if (n.ops.empty()) {
                         last_postfix_expr_was_pointer = true;
                     }

source/parse.h

@@ -847,6 +847,10 @@ struct declaration_node
     source_position pos;
     std::unique_ptr<unqualified_id_node> identifier;
 
+    token const* dereference = nullptr;
+    int dereference_cnt = 0;
+    token const* address_of  = nullptr;
+
     enum active { function, object };
     std::variant<
         std::unique_ptr<function_type_node>,
@@ -2876,6 +2880,19 @@ class parser
                 }
             }
 
+            if (deduced_type) {
+                if (peek(1)->type() == lexeme::Ampersand) {
+                    n->address_of  = &curr();
+                } 
+                else if (peek(1)->type() == lexeme::Multiply) {
+                    n->dereference = &curr();
+                    n->dereference_cnt = 1;
+                    while(peek(n->dereference_cnt+1)->type() == lexeme::Multiply) {
+                        n->dereference_cnt += 1;
+                    }
+                }
+            }
+
             if (!(n->initializer = statement(semicolon_required, n->equal_sign))) {
                 error("ill-formed initializer");
                 next();