Fix regression where function overload candidates might not be reported and add test.

Author: marsupial

CMakeLists.txt

@@ -267,8 +267,8 @@ TESTSUITE ( and-or-not-synonyms aastep arithmetic array array-derivs array-range
             operator-overloading
             oslc-comma oslc-D
             oslc-err-arrayindex oslc-err-closuremul oslc-err-field
-            oslc-err-format oslc-err-funcredef oslc-err-intoverflow
-            oslc-err-noreturn oslc-err-notfunc
+            oslc-err-format oslc-err-funcoverload oslc-err-funcredef
+            oslc-err-intoverflow oslc-err-noreturn oslc-err-notfunc
             oslc-err-outputparamvararray oslc-err-paramdefault
             oslc-err-struct-array-init oslc-err-struct-ctr
             oslc-err-struct-dup

src/liboslcomp/typecheck.cpp

@@ -1101,7 +1101,7 @@ class CandidateFunctions {
             default: break;
         }
 
-        int ambiguity = 0;
+        int ambiguity = -1;
         std::pair<const Candidate*, int> c = { nullptr, -1 };
         for (auto& candidate : m_candidates) {
             // re-score based on matching return value
@@ -1111,7 +1111,7 @@ class CandidateFunctions {
                 ambiguity = candidate.rscore;
         }
 
-        if (ambiguity || strict) {
+        if ((ambiguity != -1) || strict) {
             ASSERT (caller);
             caller->warning( "call to '%s' is ambiguous", m_candidates[0].name());
             for (auto& candidate : m_candidates) {
@@ -1392,6 +1392,9 @@ ASTfunction_call::typecheck (TypeSpec expected)
         return typecheck_struct_constructor ();
     }
 
+    // Save the current symbol to maybe report an error later.
+    FunctionSymbol *poly = func();
+
     CandidateFunctions candidates(m_compiler, expected, args(), func());
     std::tie(m_sym, m_typespec) = candidates.best(this);
 
@@ -1418,8 +1421,10 @@ ASTfunction_call::typecheck (TypeSpec expected)
     // message.
 	candidates.reportError(this, m_name);
 
-    for (FunctionSymbol *poly = func();  poly;  poly = poly->nextpoly())
+    while (poly) {
         candidates.reportAmbiguity(poly);
+        poly = poly->nextpoly();
+    }
 
     return TypeSpec();
 }

testsuite/oslc-err-funcoverload/ref/out.txt

@@ -0,0 +1,11 @@
+test.osl:8: error: No matching function call to 'funca ()'
+test.osl:3 candidate function:
+	void funca (int, int)
+test.osl:2 candidate function:
+	void funca (int)
+test.osl:9: error: No matching function call to 'funca (int, int, int)'
+test.osl:3 candidate function:
+	void funca (int, int)
+test.osl:2 candidate function:
+	void funca (int)
+FAILED test.osl

testsuite/oslc-err-funcoverload/run.py

@@ -0,0 +1,5 @@
+#!/usr/bin/env python
+
+# command = oslc("test.osl")
+# don't even need that -- it's automatic
+failureok = 1     # this test is expected to have oslc errors

testsuite/oslc-err-funcoverload/test.osl

@@ -0,0 +1,11 @@
+
+void funca(int a) {}
+void funca(int a, int b) {}
+
+
+shader test()
+{
+    funca();
+    funca(1,2,3);
+}
+